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  • 1
    Electronic Resource
    Electronic Resource
    Isolation of Fenitrothion-degrading Strain Burkholderia sp. FDS-1 and Cloning of mpd Gene (2006)
    Springer
    Biodegradation 17 (2006), S. 275-283 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; Burkholderia ; fenitrothion ; mpd gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A short rod shaped, gram-negative bacterium strain Burkholderia sp. FDS-1 was isolated from the sludge of the wastewater treating system of an organophosphorus pesticides manufacturer. The isolate was capable of using fenitrothion as the sole carbon source for its growth. FDS-1 first hydrolyzed fenitrothion to 3-methyl-4-nitrophenol, which was further metabolized to nitrite and methylhydroquinone. The addition of other carbon source and omitting phosphorus source had little effect on the hydrolysis of fenitrothion. The gene encoding the organophosphorus hydrolytic enzyme was cloned and sequenced. The sequence was similar to mpd, a gene previously shown to encode a parathion-methyl-hydrolyzing enzyme in Plesiomonas sp. M6. The inoculation of strain FDS-1 (106 cells g−1) to soil treated with 100 mg fenitrothion emulsion kg−1 resulted in a higher degradation rate than in noninoculated soils regardless of the soil sterilized or nonsterilized. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-7130-2
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  • 2
    Electronic Resource
    Electronic Resource
    The Impact of Bioaugmentation on Metal Cyanide Degradation and Soil Bacteria Community Structure (2006)
    Springer
    Biodegradation 17 (2006), S. 207-217 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; DGGE ; K2Ni(CN)4 soil bacterial populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Metal cyanides are significant contaminants of many soils found at the site of former industrial activity. In this study we isolated bacteria capable of degrading ferric ferrocyanide and K2Ni(CN)4. One of these bacteria a Rhodococcus spp. was subsequently used to bioaugment a minimal medium broth, spiked with K2Ni(CN)4, containing 1 g of either an uncontaminated topsoil or a former coke works site soil. Degradation of the K2Ni(CN)4 was observed in both soils, however, bioaugmentation did not significantly impact the rate or degree of K2Ni(CN)4 removal. Statistical analysis of denaturing gradient gel electrophoresis profiles showed that the topsoil bacterial community had a higher biodiversity, and its structure was not significantly affected by either K2Ni(CN)4 or bioaugmentation. In contrast, profiles from the coke works site indicated significant changes in the bacterial community in response to these additions. Moreover, in both soils although bioaugmentation did not affect rates of biodegradation the Rhodococcus spp. did become established in the communities in broths containing both top and coke works soil. We conclude that bacterial communities from contaminated soils with low biodiversity are much more readily perturbed through interventions such as contamination events or bioaugmentation treatments and discuss the implications of these findings for bioremediation studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-4219-6
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetics of Aerobic Polymer Degradation in Soil by Means of the ASTM D 5988-96 Standard Method (1999)
    Springer
    Journal of polymers and the environment 7 (1999), S. 109-116 
    Details
    ISSN: 1572-8900
    Keywords: Kinetics ; aerobic ; biodegradation ; poly-3-hydroxybutyrate ; poly-ɛ-caprolactone ; ASTM D 5988-96
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The standard test method ASTM D 5988-96 for determining the degree and rate of aerobic biodegradation of plastic materials in contact with soil was applied to poly(3-hydroxybutyrate) and poly(ɛ-caprolactone). The method proved to be reliable and supplied reproducible measurements of CO2 production, provided potassium (instead of barium) hydroxide was used as a trapping solution. The trends of CO2 evolution, as a function of time, observed for the degradation of polymer powders in soil are similar to those predicted by simple first order kinetics in solution. The experimental data are described by a Michaelis–Menten type model, which accounts for the heterogeneity of the polymer-soil system. The kinetic equation deduced predicts the degradation rate to the proportional to the exposed polymer surface area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021864402395
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  • 4
    Electronic Resource
    Electronic Resource
    Thermodynamic and Diffusion Properties of Biodegradable Systems Based on Starch and Cellulose Derivatives (1999)
    Springer
    Journal of polymers and the environment 7 (1999), S. 35-40 
    Details
    ISSN: 1572-8900
    Keywords: Starch ; starch blends ; sorption ; diffusion ; biodegradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The interval sorption and diffusion of water vapor were studied for two systems: methylcellulose (MC)/starch and carboxymethylcellulose (CMC)/starch. The diffusion coefficient of water vapor and the Gibbs free energy of swelling of these blends in water were estimated. The Gibbs free energy of mixing starch with the cellulose derivatives was determined using the thermodynamic cycle. CMC/starch was shown to be more compatible than MC/starch. Biodegradation of these systems in the water–soil environment was measured and found to increase with the concentration of starch in its blends with cellulose derivatives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021842118866
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of Crystalline and Amorphous Structures on Biodegradability of Poly(Tetramethylene Succinate) (1999)
    Springer
    Journal of polymers and the environment 7 (1999), S. 19-26 
    Details
    ISSN: 1572-8900
    Keywords: Poly(tetramethylene succinate) ; amorphous and crystalline orientation ; biodegradation ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of orientation in the amorphous and crystalline regions on the biodegradability of PTMS [poly(tetramethylene succinate)] was studied using the amorphous orientation function, birefringence, and crystallinity. The crystalline and amorphous intrinsic lateral sonic moduli, E t,c 0 and E t,am 0 , were 2.61 × 103 and 0.41 × 103 MPa, respectively. Using the data on birefringence, crystalline and amorphous orientation function (f ∈ and f am), crystallinity, and sonic modulus of the oriented PTMS fibers, the intrinsic birefringence of the crystalline (Δ c 0 ) and amorphous (Δ am 0 ) regions were evaluated to be 0.0561 and 0.0634, respectively. The biodegradabilities of oriented PTMS films were reduced as the elongation increased, i.e., the amorphous orientation increased. At low elongation (100 and 150%), however, biodegradabilities remained unchanged when the degradation test was performed in activated sludge, which was attributed to the amorphous orientation occurring even at 100% elongation, though the amorphous orientation direction was perpendicular to the fiber axis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021838017958
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  • 6
    Electronic Resource
    Electronic Resource
    Comparisons of Geochemical Signatures of Biotransformation of Fuel Hydrocarbons in Groundwater (1999)
    Springer
    Environmental monitoring and assessment 59 (1999), S. 257-274 
    Details
    ISSN: 1573-2959
    Keywords: biodegradation ; groundwater geochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Biotransformation processes play an active role in reducing the environmental impact of fuel hydrocarbon releases to groundwater. Because monitoring data at release locations are typically sparse, spatial variations in geochemical indicator parameters are often called upon as indirect evidence of biotransformation. These parameters include concentrations of electron acceptors (O2, NO3 -, SO〉 4 2- , reduced redox reaction by-products (Fe2+, Mn2+, CH4), as well as bicarbonate alkalinity, pH and Eh. However, background variability in a number of these parameters complicates the task of data interpretation, particularly in the case of small data sets. In this study, correlation analyses are applied to geochemical indicator data at six hydrocarbon groundwater contamination sites in California to identify which parameters are the most reliable indicators. The results of the analyses suggest that the most direct indicators of the local redox environment – Fe2+, Mn2+, CH4, Eh – yield the most consistent evidence of hydrocarbon biotransformation. Indicators which rely largely on mass balance – O2, NO 3 - , SO 4 2- , alkalinity – appear to be less reliable. These findings may provide guidance in both the collection and interpretation of groundwater monitoring data at hydrocarbon contamination sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006113520693
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  • 7
    Electronic Resource
    Electronic Resource
    Modeling Microbial Transport and Biodegradation in a Dual-porosity System (1999)
    Springer
    Transport in porous media 35 (1999), S. 49-65 
    Details
    ISSN: 1573-1634
    Keywords: modeling ; biodegradation ; microbial transport ; dual-porosity ; kinetics.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract A mathematical model describing microbial transport and growth in a heterogeneous aquifer domain, composed of overlapping subdomains of high-permeability and low-permeability materials, is developed. Each material is conceptually visualized as a continuum which occupies the entire considered spatial aquifer domain. Based on the assumption that advection in the low-permeability domain is negligible, the mathematical model is solved by using a publically available reactive transport code. The importance of modeling microbial transport and growth in such a dual-porosity system is demonstrated through a hypothetical case study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006551627151
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  • 8
    Electronic Resource
    Electronic Resource
    Anaerobic biodegradation of BTEX and gasoline in various aquatic sediments (1999)
    Springer
    Biodegradation 10 (1999), S. 15-25 
    Details
    ISSN: 1572-9729
    Keywords: anaerobic ; biodegradation ; BTEX ; gasoline ; hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We examined the extent of biodegradation of benzene, toluene, ethylbenzene and the three isomers of xylene (BTEX) as a mixture and from gasoline in four different sediments: the New York/New Jersey Harbor estuary (polluted); Tuckerton, N.J. (pristine); Onondaga Lake, N.Y. (polluted) and Blue Mtn. Lake, N.Y. (pristine). Enrichment cultures were established with each sediment using denitrifying, sulfidogenic, methanogenic and iron reducing media, as well as site water. BTEX loss, as measured by GC-FID, was extensive in the sediments which had a long history of pollution, with all compounds being utilized within 21–91 days in the most active cultures, and was very slight or non-existent in the pristine sediments. Also, the pattern of loss was different under the various reducing conditions within each sediment and between sediments. For example benzene loss was only observed in sulfidogenic cultures from the NY/NJ Harbor sediments while toluene was degraded under all redox conditions. The loss of BTEX was correlated to the reduction of the various electron acceptors. In cultures amended with gasoline the degradation was much slower and incomplete. These results show that the fate of the different BTEX components in anoxic sediments is dependent on the prevailing redox conditions as well as on the characteristics and pollution history of the sediment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008303729431
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of nitrogen and phosphorus addition on phenanthrene biodegradation in four soils (1999)
    Springer
    Biodegradation 10 (1999), S. 43-50 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; nitrogen ; nutrients ; phenanthrene ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phenanthrene mineralization rates were found to vary widely among four soils; differences in soil nutrient levels was one hypothesis to explain this variation. To test this hypothesis, phenanthrene mineralization rates were measured in these soils with, and without, added nitrogen and phosphorus. Mineralization rates either remained unchanged or were depressed by the addition of nitrogen and phosphorus. Phenanthrene degradation rates remained unchanged in the soil which had the highest indigenous levels of nitrogen and phosphorus and which showed the largest increase in phosphorus levels after nutrients were added. The soils in which degradation rates were depressed had lower initial phosphorus concentrations and showed much smaller or no measurable increase in phosphorus levels after nutrients were added to the soils. To understand the response of phenanthrene degradation rates to added nitrogen and phosphorus, it may be necessary to consider the bioavailability of added nutrients and nutrient induced changes in microbial metabolism and ecology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008359606545
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  • 10
    Electronic Resource
    Electronic Resource
    Growth inhibition of biomass adapted to the degradation of toluene and xylenes in mixture in a batch reactor with substrates supplied by pulses (1999)
    Springer
    Biodegradation 10 (1999), S. 245-250 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; growth inhibition ; metabolites ; toluene ; xylenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A biomass adapted to degrade toluene and xylenes in mixture was grown in a batch reactor with substrates supplied by pulses. The inhibition of biomass growth in the course of substrate degradation was investigated. The maximal biomass concentration of 7 g l−1 was obtained using 150 μl of toluene and 15 μl of a mixture of xylenes in one litre of liquid medium, and the maximal biomass productivity and yield were 53 mg l−1 h−1 and 0.32 gDW g s −1 , respectively. Higher quantities of substrate added by pulses, that is 200 μl of toluene with 20 μl of xylenes and 300 μl of toluene with 30 μl of xylenes, caused an accumulation of metabolites. These higher quantities of substrates caused inhibition of microbial growth. Among the metabolites produced, 4-methyl catechol was found in large quantities in the culture medium and in the cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008363422254
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  • 11
    Electronic Resource
    Electronic Resource
    A comparison of the ability of forest and agricultural soils to mineralize chlorinated aromatic compounds (1999)
    Springer
    Biodegradation 10 (1999), S. 235-244 
    Details
    ISSN: 1572-9729
    Keywords: Atrazine ; biodegradation ; chlorophenolics ; 2,4-D ; PCP ; pristine soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soils were sampled from two agricultural fields, two relatively pristine forests, and one suburban forest in Ontario, Canada. The ability of these soils to mineralize 2,4-dichlorophenoxyacetate, 3-chlorobenzoate, 4-chlorophenol, 2,4-dichlorophenol, pentachlorophenol, and atrazine was determined using 14C-labeled substrates. Direct preexposure was necessary before atrazine mineralization could be detected; however, it was not necessary for degradation of any of the other chemicals. 2,4-dichlorophenoxyacetate and pentachlorophenol mineralization was much higher in the agricultural soils relative to the pristine forest soils, but 3-chlorobenzoate and 2,4-dichlorophenol mineralization rates showed the opposite trend. Mineralization of 4-chlorophenol was about equivalent in all soils. Suburban forests soils were indistinguishable from agricultural soils with respect to their degradation of 2,4-dichlorophenoxyacetate and chlorobenzoate. Additionally, they were better able than any of the soils to withstand the toxic effects of pentachlorophenol. Pentachlorophenol mineralization was highly variable in the pristine forest soils, ranging from about 6 to 50%. Abiotic factors such as pH, soil type, and organic and moisture content did not account for these significant site differences. The selective forces responsible for these differences, and the possible differences in microbial populations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008365606324
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  • 12
    Electronic Resource
    Electronic Resource
    Biofilter performance and characterization of a biocatalyst degrading alkylbenzene gases (1999)
    Springer
    Biodegradation 10 (1999), S. 169-176 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; biofiltration ; bioremediation ; extremophile ; VOC ; waste gas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A biofilter treating alkylbenzene vapors was characterized for its optimal running conditions and kinetic parame-ters. Kinetics of the continuous biofilter were compared to batch kinetic data obtained with biofilm samples as well as with defined microbial consortia and with pure culture isolates from the biofilter. Both bacteria and fungi were present in the bioreactor. Five strains were isolated. Two bacteria, Bacillus and Pseudomonas, were shown to be dominant, as well as a Trichosporon strain which could, however, hardly grow on alkylbenzenes in pure culture. The remaining two strains were most often overgrown by the other three organisms in liquid phase batch cultures μ max, KS, KI values and biodegradation rates were calculated and compared for the difterent mixed and pure cultures. Since filter bed acidification was observed during biofiltration studies reaching a pH of about 4, experiments were also undertaken to study the influence of pH on performance of the different cultures. Biodegradation and growth were possible in all cases, over the pH range 3.5–7.0 at appreciable rates, both with mixed cultures and with pure bacterial cultures. Under certain conditions, microbial activity was even observed in the presence of alkylbenzenes down to pH 2.5 with mixed cultures, which is quite unusual and explains the ability of the present biocatalyst to remove alkylbenzenes with high efficiency in biofilters under acidic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008301415192
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  • 13
    Electronic Resource
    Electronic Resource
    Biodegradation of xylene and butyl acetate using an aqueous-silicon oil two-phase system (1999)
    Springer
    Biodegradation 10 (1999), S. 193-200 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; butyl acetate ; selection of microorganisms ; silicon oil ; two-phase aqueous-organic system ; xylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A stable microbial population, consisting of seven bacterial strains and three yeast strains, was selected in batch cultures on a mixture of ortho and meta-xylene and butyl acetate as the sole source of carbon and energy. This population can completely degrade up to 10 g/L of a mixture of these xenobiotics (70% xylene and 30% butyl acetate wt/wt) in a two-phase aqueous-silicone oil system (70%/30% vol/vol) within 96 h, while for the usual one-phase system very low growth degradation rates were observed. Further organic solvents were tested and finally, silicon oil was selected as the best organic phase for such a two-phase system. With periodical pH adjustments to 6.0 in fed-batch mode, the culture showed a global degradation rate of 63 mg L-1 h-1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008328318442
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  • 14
    Electronic Resource
    Electronic Resource
    Modelling the growth of a methanotrophic biofilm: Estimation of parameters and variability (1999)
    Springer
    Biodegradation 10 (1999), S. 177-191 
    Details
    ISSN: 1572-9729
    Keywords: AQUASIM ; biodegradation ; biofilm ; growth ; kinetics ; methane ; modelling ; nitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This article discusses the growth of methanotrophic biofilms. Several independent biofilm growths scenarios involving different inocula were examined. Biofilm growth, substrate removal and product formation were monitored throughout the experiments. Based on the oxygen consumption it was concluded that heterotrophs and nitrifiers co-existed with methanotrophs in the biofilm. Heterotrophic biomass grew on soluble polymers formed by the hydrolysis of dead biomass entrapped in the biofilm. Nitrifier populations developed because of the presence of ammonia in the mineral medium. Based on these experimental results, the computer program AQUASIM was used to develop a biological model involving methanotrophs, heterotrophs and nitrifiers. The modelling of six independent growth experiments showed that stoichiometric and kinetic parameters were within the same order of magnitude. Parameter estimation yielded an average maximum growth rate for methanotrophs, μm, of 1.5 ± 0.5 d−1, at 20 °C, a decay rate, bm, of 0.24 ± 0.1 d−1, a half saturation constant, $${\text{K}}_{{\text{S(CH}}_{\text{4}} {\text{)}}} $$ , of 0.06 ± 0.05 mg CH4/L, and a yield coefficient, $$Y_{CH_4 } $$ , of 0.57 ±: 0.04 g X/g CH4. In addition, a sensitivity analysis was performed on this model. It indicated that the most influential parameters were those related to the biofilm (i.e. density; solid-volume fraction; thickness). This suggests that in order to improve the model, further research regarding the biofilm structure and composition is needed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008317906069
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  • 15
    Electronic Resource
    Electronic Resource
    Two-liquid-phase bioreactors for enhanced degradation of hydrophobic/toxic compounds (1999)
    Springer
    Biodegradation 10 (1999), S. 219-233 
    Details
    ISSN: 1572-9729
    Keywords: bioavailability ; biodegradation ; bioreactor ; biotreatment ; NAPL ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two-liquid-phase culture systems involve the addition of a water-immiscible, biocompatible and non-biodegradable solvent to enhance a biocatalytic process. Two-liquid-phase bioreactors have been used since the mid-seventies for the microbial and enzymatic bioconversion of hydrophobic/toxic substrates into products of commercial interest. The increasing popularity of bioremediation technologies suggests a new area of application for this type of bioreactor. The toxicity and the limited bioavailability of many pollutants are important obstacles that must first be overcome in order to improve biodegradation processes. Two-liquid-phase bioreactors have the potential to resolve both limitations of biotreatment technologies by the enhancement of the mass-transfer rate of compounds with low bioavailability, and by the controlled delivery of apolar toxic compounds. This technology can also be useful in accelerating the enrichment of microorganisms degrading problematic pollutants. In this paper, we discuss the application of two-liquid-phase bioreactors to enhance the biodegradation of toxic/poorly bioavailable contaminants. Important microbial mechanisms involved in this type of system are described. Uptake of the substrates can be achieved by microorganisms freely dispersed in the aqueous phase and/or bound at the interface between the aqueous and the immiscible phases. Production of surface-active compounds and adhesion abilities are microbial features involved in the process. General guidelines for the design of two-liquid-phase bioreactors for biodegradation purposes are presented. Solvent selection should be established on specific criteria, which depend on the characteristics of target compound(s) and the microorganism(s) implicated in the biodegradation process. The central importance of maximizing the interfacial surface area is highlighted. The potential of this approach as an alternative to current biotreatment technologies is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008311430525
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  • 16
    Electronic Resource
    Electronic Resource
    Degradation of mono-chlorophenols by a mixed microbial community via a meta- cleavage pathway (1999)
    Springer
    Biodegradation 10 (1999), S. 353-362 
    Details
    ISSN: 1572-9729
    Keywords: mixed microbial community ; mono-chlorophenol ; biodegradation ; 3-chlorocatechol ; 5-chloro-2-hydroxymuconic semialdehyde ; meta- cleavage pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A mixed microbial community, specially designed todegrade a wide range of substituted aromaticcompounds, was examined for its ability to degrademono-chlorophenols as sole carbon source in aerobicbatch cultures. The mixed culture degraded 2-, 3-, and4 -chlorophenol (1.56 mM) via a meta- cleavagepathway. During the degradation of 2- and3-chlorophenol by the mixed culture, 3-chlorocatecholproduction was observed. Further metabolism was toxicto cells as it led to inactivation of the catechol2,3-dioxygenase enzyme upon meta- cleavage of3-chlorocatechol resulting in incomplete degradation.Inactivation of the meta- cleavage enzyme led toan accumulation of brown coloured polymers, whichinterfered with the measurement of cell growth usingoptical denstiy. Degradation of 4-chlorophenol by themixed culture led to an accumulation of5-chloro-2-hydroxymuconic semialdehyde, themeta- cleavage product of 4-chlorocatechol. Theaccumulation of this compound did not interfere withthe measurement of cell growth using optical density.5-chloro-2-hydroxymuconic semialdehyde was furthermetabolized by the mixed culture with a stoichiometricrelease of chloride, indicating complete degradationof 4-chlorophenol by the mixed culture via ameta- cleavage pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008323811433
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  • 17
    Electronic Resource
    Electronic Resource
    Removal and recovery of metal cyanides using a combination of biosorption and biodegradation processes (1999)
    Springer
    Biotechnology letters 21 (1999), S. 913-919 
    Details
    ISSN: 1573-6776
    Keywords: biodegradation ; biosorption ; Cladosporium cladosporioides ; copper cyanide ; nickel cyanide ; recovery ; removal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Cladosporium cladosporioides biomass was a highly efficient biosorbent of copper cyanide and nickel cyanide from aqueous solutions. A 32–38 fold concentration of initial 0.5 mM metal cyanides could be achieved when biosorption process was carried out under standardised conditions. Residual, unrecoverable metal cyanide could be completely biodegraded in 5–6 h. The solution treated with the combined biosorption-biodegradation process was fit for discharge in the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005550707798
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  • 18
    Electronic Resource
    Electronic Resource
    Degradation of biphenyl by methanogenic microbial consortium (1999)
    Springer
    Biotechnology letters 21 (1999), S. 741-745 
    Details
    ISSN: 1573-6776
    Keywords: anaerobic microbial consortium ; biodegradation ; bioremediation ; biphenyl ; p-cresol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Biphenyl was readily degraded and mineralized to CO2 and CH4 by a PCB-dechlorinating anaerobic microbial consortium. Degradation occurred when biphenyl was supplied as a sole source of carbon or as a co-metabolic substrate together with glucose and methanol. p-Cresol was detected and confirmed by mass spectroscopy as a transient intermediate. Production of 14 C-CO2 and 14C-CH4 from 14C-biphenyl was observed in the approximate ratio of 1:2. The results indicated the existence of novel pathways for biphenyl degradation in a natural anaerobic microbial community.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005586926683
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  • 19
    Electronic Resource
    Electronic Resource
    Degradation of polychlorinated biphenyls by a ‘Maitake’ mushroom, Grifola frondosa (1999)
    Springer
    Biotechnology letters 21 (1999), S. 27-31 
    Details
    ISSN: 1573-6776
    Keywords: PCBs ; biodegradation ; mushroom ; Grifola frondosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The edible mushroom ‘Maitake’, Grifola frondosa M51, degraded 40 components in the 41 major peaks of polychlorinated biphenyls (PCBs), which includes di- to hexa-chlorobiphenyls, within 60 days. The organism accumulated dichloro-methoxy-phenol during the transformation of the PCB mixture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005457201291
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  • 20
    Electronic Resource
    Electronic Resource
    Sporulation as an effective strategy for the survival of bacteria in a biofilter with discontinuous operation (1999)
    Springer
    Biotechnology letters 21 (1999), S. 835-838 
    Details
    ISSN: 1573-6776
    Keywords: Bacillus sp. ; biodegradation ; contaminated air ; sporulation ; waste
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The microbial population of the biofilter developed for the treatment of air contaminated by solvent vapours was evaluated using plate count techniques. The number of total heterotrophic bacteria and bacteria utilizing contaminant as the only source of carbon and energy was estimated during the exchange of the filter-bed material and start-up of its operation. Spore-forming bacteria (Bacillus spp.) occupied a significant part of the filter-bed niche. It is proposed that sporulation helps bacteria to survive during the breaks in operation of the biofilter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005599312571
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  • 21
    Electronic Resource
    Electronic Resource
    Potential for Enhancement of Biodegradation of Crude Oil in Louisiana Salt Marshes using Nutrient Amendments (1999)
    Springer
    Water, air & soil pollution 109 (1999), S. 343-355 
    Details
    ISSN: 1573-2932
    Keywords: biodegradation ; crude oil ; salt marshes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Salt marsh ecosystems in Louisiana are at high risk of an oil contamination event while remediation of these systems is mainly limited to intrinsic bioremediation due to the physical sensitivity of salt marshes. This study investigated both the intrinsic and nutrient enhanced rates of crude oil degradation both in microcosm and core studies. In addition, limiting elements, loading rates and optimum nitrogen forms (NH 4 + or NO 3 - ) were determined. Salt marshes have relatively low intrinsic degradation rates (0–3.9% day-1) of the alkane component (C11-C44) but high rates (8–16% day-1) of degradation of the polycyclic aromatic hydrocarbon (PAH) fraction (naphthalene, C1, and C2-Naphthalene and Phenanthrene, C1, and C2-Phenanthrene). Additions of nitrogen statistically enhanced degradation of many alkanes and total PAHs while naturally present phosphorous was found to be sufficient. Nitrogen was found to be most effective if applied as NH 4 + in the range of 100-500-N mg kg-1 of soil producing a pore water range of 100-670-N mg L-1. Core studies indicate that similar trends are observed when applying fertilizers to intact portions of salt marsh.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005025809014
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  • 22
    Electronic Resource
    Electronic Resource
    Effects of Nitrogen and Phosphorus Supply on Hexadecane Biodegradation in Soil Systems (1999)
    Springer
    Water, air & soil pollution 111 (1999), S. 1-18 
    Details
    ISSN: 1573-2932
    Keywords: biodegradation ; hydrocarbon ; nitrogen ; nutrient ratios ; phosphorus ; soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The biodegradation of hexadecane (C as hexadecane-C) was assessed under 34 different external nitrogen (N supplied as NO3-N) and phosphorus (P supplied as PO4-3-P) supply conditions in order to determine how different nutrient formulations affected nutrient limitation conditions during degradation. CO2 production yields indicated that shifts in N and P supply levels resulted in variable biodegradation responses due to shifts in the limiting-nutrient (e.g., from N to P). For example, the estimated maximum fractional CO2 yield ratio was 0.24 (mg CO2-C produced mg-1 hexadecane-C) for P-limited nutrient formulations (P:hexadecane-C〈0.01), whereas the yield ratio was more than two times greater when the system was not P- limited. Similar effects were observed for N-limited (N:hexadecane- C〈0.15) versus non-N-limited formulations. The relative bioavailability of natural soil-N and soil-P also was examined. In the soil studied, background soil-N was 96.3% organic-N and was found to be largely nonbioavailable. In contrast, high CO2 yields were observed even when no external P was supplied. An iterative mathematical procedure indicated that the Olsen soil-P subfraction (inorganic soil-P plus soluble organic soil- P) best approximated bioavailable soil-P for this soil. Our results indicate that both N and P additions affect biodegradation yields, but that stoichiometrically inappropriate nutrient mixes produce suboptimal CO2 yields. We also found that the bioavailable fractions of soil-N and soil-P should be incorporated into estimating the most suitable nutrient formulations for a given contamination scenario.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005091427942
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  • 23
    Electronic Resource
    Electronic Resource
    Performance and efficiency of a yeast biofilter for the treatment of a Nigerian fertilizer plant effluent (1999)
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 515-516 
    Details
    ISSN: 1573-0972
    Keywords: Biofilter ; biodegradation ; effluent ; fertilizer ; immobilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A biofilter composed of yeasts and cassava peel was used to detoxify fertilizer plant effluent. The biological oxygen demand was reduced on treatment from a range of 1200–1400 mg/l to a range 135–404 mg/l. The ammonia-nitrogen (NH3–N) and nitrate-nitrogen (NO3–N) were reduced after treatment from 1000 to 10 mg/l and from 100 to 17.6 mg/l, respectively. The biofilter is simple and easy to handle with high efficiency of 98%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008931824416
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  • 24
    Electronic Resource
    Electronic Resource
    Biodegradation of Polyaromatics Synthesized by Peroxidase-Catalyzed Free-Radical Polymerization (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 115-120 
    Details
    ISSN: 1572-8900
    Keywords: Polyaromatics ; free-radical polymerization ; biodegradation ; peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Polymers formed from peroxidase-based free-radical polymerization reactions were characterized for rates of mineralization against lignin and humic acid controls. Degradation studies were carried out in soil systems over 202 days and cumulative net CO2 was determined. Whereas mineralization of the humic acid and alkali lignin controls totaled ca. 20% at the end of the test exposure, there was essentially no net mineralization of the hydrolytic lignin control. Mineralization of the test samples totaled 5% for poly(p-ethylphenol) and 11% for poly(m-cresol). At the same time, mineralization of the poly(p-phenyl phenol) totaled 64%. Conversely, the readily biodegradable polymers cellulose and PHB reached values of 91 to 97% in less than 60 days. Our data suggest that the mineralization kinetics of the enzymatically derived polyaromatics mimic those of the naturally occurring heteropolymers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021809228436
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  • 25
    Electronic Resource
    Electronic Resource
    Degradation of Poly(Ethylene Glycol)-Based Nonionic Surfactants by Different Bacterial Isolates from River Water (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 121-131 
    Details
    ISSN: 1572-8900
    Keywords: Nonionic surfactants ; biodegradation ; alkylphenol poly(ethoxylate)s ; alkyl poly(ethoxylate)s ; polyethylene glycol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Different bacterial strains able to attack polyoxyethylene-type nonionic surfactants were isolated by enrichment procedure from the surface waters of the Arno River. Alkylphenol polyethoxylates and alkyl polyethoxylates, as well as polyethylene glycols, were degraded and assimilated by bacterial strains in axenic cultures. Degradative routes of polyethyleneoxide chains were investigated by matching each bacterial isolate with several types of nonionic surfactants and polyethers and by the identification of their degradation products isolated during aerobic digestion experiments. In accordance with previous reports, the first attack led to the shortening of the poly(oxyethylene) chains of the nonionic surfactants. It was found that the strains able to degrade PEG segments of nonionic surfactants possess enzymatic systems unable to degrade free PEGs, whereas those degrading the latter substrates cannot degrade PEG segments coupled to hydrophobic moieties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021813312506
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  • 26
    Electronic Resource
    Electronic Resource
    Synthesis, Characterization, and Hydrolytic Degradation of Copolymers of 2-Methylene-1,3-dioxepane with Ethylene and with Styrene (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 23-29 
    Details
    ISSN: 1572-8900
    Keywords: Polyethylene ; polystyrene ; biodegradation ; copolymerization ; hydrolytic degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract 2-Methylene-1,3-dioxepane (MDP) was copolymerized with ethylene (E) at a pressure of approximately 1000 psi and a temperature of approximately 70°C with AIBN as the free radical initiator. The copolymers obtained, poly(MDP-co-E), were characterized by elemental analysis, IR, 1H-NMR and 13C-NMR spectroscopy, DSC, and GPC. The copolymers contained 2–15 mol% ester units. MDP was also copolymerized with styrene (S) at 120°C with di-t-butyl peroxide as the initiator to prepare the copolymer, poly(MDP-co-S). The number-average molecular weights of both types of copolymers were in the range of 6000 to 11,000, and the weight-average molecular weights were in the range of 9000 to 17,000. The melting temperatures of poly(MDP-co-E) decreased with increasing ester unit content in the copolymer. For the MDP-S copolymers, the glass transition temperatures decreased with increasing ester unit content. Both poly(MDP-co-E) and poly(MDP-co-S) were degraded by methanolysis, and their molecular weights decreased by the expected amounts based on the ester unit content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022874411834
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  • 27
    Electronic Resource
    Electronic Resource
    Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 91-98 
    Details
    ISSN: 1572-8900
    Keywords: Starch ; PHBV ; PHA ; plastic ; blends ; biodegradation ; soil ; compost
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV 〈 30% starch 〈 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by 1H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022806222158
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  • 28
    Electronic Resource
    Electronic Resource
    Evaluation of the Biodegradation of Starch and Cellulose Under Controlled Composting Conditions (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 197-202 
    Details
    ISSN: 1572-8900
    Keywords: Starch ; cellulose ; biodegradation ; ISO/DIS 14855:1997 ; ASTM D 5338-92 ; priming effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In order to verify the response of the controlled composting test method (i.e., the ISO/DIS 14855:1997, the ASTM D 5338-92, or the CEN counterpart) to starch at different concentrations, the maximum amount prescribed by the test method (100 g) and lower amounts (60 and 30 g), as if starch were a coingredient in a blend, were tested. After 44 days of incubation (at a constant temperature of 58°C) the biodegradation curves were in a plateau phase, displaying the following final values (referred to a nominal starch initial amount of 100 g): starch 100 g, 97.5%; starch 60 g, 63.7%; and starch 30 g, 32.5%. The data show a CO2 evolution roughly equal, in each case, to the theoretical maximum, indicating a complete starch mineralization. We cannot discern whether the deviations found at lower concentrations are caused by a priming effect. In any case, the extent of the deviations is not high and is acceptable in biodegradation studies. The average biodegradation of cellulose, obtained gathering four independent experiments with 11 biodegradation curves, turned out to be 96.8 ± 6.7% (SD) after 47 ± 1 days. The data indicate that the controlled composting is a reliable test method also for starch and cellulose and, consequently, for starch-based and cellulose-based materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021825715232
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  • 29
    Electronic Resource
    Electronic Resource
    Molecular Weight Changes and Polymeric Matrix Changes Correlated with the Formation of Degradation Products in Biodegraded Polyethylene (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 187-195 
    Details
    ISSN: 1572-8900
    Keywords: LDPE ; biodegradation ; molecular weight changes ; degradation products
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The molecular weight changes in abiotically and biotically degraded LDPE and LDPE modified with starch and/or prooxidant were compared with the formation of degradation products. The samples were thermooxidized for 6 days at 100°C to initiate degradation and then either inoculated with Arthobacter paraffineus or kept sterile. After 3.5 years homologous series of mono- and dicarboxylic acids and ketoacids were identified by GC-MS in abiotic samples, while complete disappearance of these acids was observed in biotic environments. The molecular weights of the biotically aged samples were slightly higher than the molecular weights of the corresponding abiotically aged samples, which is exemplified by the increase in $$\overline M _n$$ from 5200 g/mol for a sterile sample with the highest amount of prooxidant to 6000 g/mol for the corresponding biodegraded sample. The higher molecular weight in the biotic environment is explained by the assimilation of carboxylic acids and low molecular weight polyethylene chains by microorganisms. Assimilation of the low molecular weight products is further confirmed by the absence of carboxylic acids in the biotic samples. Fewer carbonyls and more double bonds were seen by FTIR in the biodegraded samples, which is in agreement with the biodegradation mechanism of polyethylene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021873631162
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  • 30
    Electronic Resource
    Electronic Resource
    Influence of Processing Additives on the Degradation of Melt-Pressed Films of Poly(ε-Caprolactone) and Poly(Lactic Acid) (1998)
    Springer
    Journal of polymers and the environment 6 (1998), S. 209-221 
    Details
    ISSN: 1572-8900
    Keywords: Poly(ε-caprolactone ; poly(lactic acid) ; processing additives ; biodegradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Melt-pressed films of polycaprolactone (PCL) and poly(lactic acid) (PLA) with processing additives, CaCO3, SiO2, and erucamide, were subjected to pure fungal cultures Aspergillus fumigatus and Penicillium simplicissimum and to composting. The PCL films showed a rapid weight loss with a minor reduction in the molecular weight after 45 days in A. fumigatus. The addition of SiO2 to PCL increased the rate of (bio)erosion in A. fumigatus and in compost. The use of a slip additive, erucamide, was shown to modify the properties of the film surface without decreasing the rate of bio(erosion). Both the rate of weight loss and the rate of molecular weight reduction of PCL increased with decreasing film thickness. The addition of CaCO3 to PLA significantly reduced the thermal degradation during processing, but it also reduced the rate of the subsequent (bio)degradation in the pure fungal cultures. PLA without additives and PLA containing SiO2 exhibited the fastest (bio)degradation, followed by PLA with CaCO3. The degradation of the PLA films was initially governed by chemical hydrolysis, followed by an acceleration of the weight change and of the molecular weight reduction. PLA film subjected to composting exhibits a rapid decrease in molecular weight, which then remains unchanged during the measurement period, probably because of crystallization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021829816140
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  • 31
    Electronic Resource
    Electronic Resource
    Incidence of keratinophilic fungi in the soil of primary schools and public parks of Madras city, India (1998)
    Springer
    Mycopathologia 143 (1998), S. 139-145 
    Details
    ISSN: 1573-0832
    Keywords: biodegradation ; dermatophytes ; dermatophytoses ; keratinophilic fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The pattern of incidence of keratinophilic fungi inhabiting the soil of 30 primary schools and 15 public parks in the city of Madras was studied using hair baiting technique. A total number of 31 species belonging to 15 genera were recovered, 16 of which were common to both the school and public park soil. Dermatophytes and closely related species were represented by 9 species, of which the following were the most commonly found species in soil: Chrysosporium tropicum (62.2%), C. keratinophilum (48.8%), M. gypseum (48.8%), C. pannorum (40%), T. mentagrophytes (37.7%), T. terrestre (31.1%) and C. anam. A. cuniculi (24.4%). The fungi encountered have also been discussed in relation to their global distribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006945012620
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  • 32
    Electronic Resource
    Electronic Resource
    Isolation of highly performant sulfate reducers from sulfate-rich environments (1998)
    Springer
    Biodegradation 9 (1998), S. 285-292 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; gypsum ; hydrogen ; inhibition ; isolation ; sulfate-reducing bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Eleven pure strains of sulfate-reducing bacteria have been isolated from lab-scale bioreactors or gypsum disposal sites, all featuring relatively high concentrations of sulfate, and from natural environments in order to produce sulfide from gypsum using hydrogen as energy source. The properties of the eleven strains have been investigated and compared to these of three collection strains i.e. Desulfovibrio desulfuricans and Dv. vulgaris and Desulfotomaculum orientis. Particular attention was paid to the volumetric and specific sulfide production rate and to the hydrogen sulfide inhibition level. By comparison to the three collection strains, a 75% higher production rate and a hydrogen sulfide inhibition level about twice as high i.e. 25.1 mM have been achieved with strains isolated from sulfate-rich environments. The strain selection, particularly from sulfate-rich environments, should be considered as an optimization factor for the sulfate reduction processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008382102417
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  • 33
    Electronic Resource
    Electronic Resource
    Microbial degradation of tannins – A current perspective (1998)
    Springer
    Biodegradation 9 (1998), S. 343-357 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; condensed tannins ; gallic acid ; hydrolysable tannins ; quercetin ; rumen ; tannase ; tannins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tannins are water-soluble polyphenolic compounds having wide prevalence in plants. Hydrolysable and condensed tannins are the two major classes of tannins. These compounds have a range of effects on various organisms – from toxic effects on animals to growth inhibition of microorganisms. Some microbes are, however, resistant to tannins, and have developed various mechanisms and pathways for tannin degradation in their natural milieu. The microbial degradation of condensed tannins is, however, less than hydrolysable tannins in both aerobic and anaerobic environments. A number of microbes have also been isolated from the gastrointestinal tract of animals, which have the ability to break tannin-protein complexes and degrade tannins, especially hydrolysable tannins. Tannase, a key enzyme in the degradation of hydrolysable tannins, is present in a diverse group of microorganisms, including rumen bacteria. This enzyme is being increasingly used in a number of processes. Presently, there is a need for increased understanding of the biodegradation of condensed tannins, particularly in ruminants.
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    URL: http://dx.doi.org/10.1023/A:1008397506963
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  • 34
    Electronic Resource
    Electronic Resource
    Influence of selected physical parameters on the biodegradation of acrylamide by immobilized cells of Rhodococcus sp. (1998)
    Springer
    Biodegradation 9 (1998), S. 381-387 
    Details
    ISSN: 1572-9729
    Keywords: acrylamide ; amidase ; biodegradation ; biotransformation ; immobilized cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influences of concentration of acrylamide, pH, temperature, duration of storage of encapsulated cells and presence of different metals and chelators on the ability of immobilized cells of a Rhodococcus sp. to degrade acrylamide were evaluated. Immobilized cells (3 g) rapidly degraded 64 and 128 mM acrylamide in 3 and 5 h, espectively, whereas free cells took more than 24 h to degrade 64 mM acrylamide. An acrylamide concentration of 128 mM inhibited the growth of the free cells. Immobilized bacteria were slow to degrade acrylamide at 10 °C. Less than 60% of acrylamide was degraded in 4 h. However, 100% of the compound was degraded in less than 3 h at 28 °C and 45 °C. The optimum pH for the degradation of acrylamide by encapsulated cells was pH 7.0. Less than 10% of acrylamide was degraded at pH 6.0, while ca. 60% of acrylamide was degraded at pH 8.0 and 8.5. Copper and nickel inhibited the degradation, suggesting the presence of sulfhydryl (-SH) groups in the active sites of the acrylamide degrading amidase. Iron enhanced the rates of degradation and chelators (EDTA and 1,10 phenanthroline) reduced the rates of degradation suggesting the involvement of iron in its active site(s) of the acrylamide-degrading-amidase. Immobilized cells could be stored up to 10 days without any detectable loss of acrylamide-degrading activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008383710019
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  • 35
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance in environmental engineering: Principles and applications (1998)
    Springer
    Biodegradation 9 (1998), S. 393-409 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; bioreactors ; NMR imaging ; NMR spectroscopy ; nutrient removal ; sludge ; solid waste
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper gives an introduction to nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) in relation to applications in the field of environmental science and engineering. The underlying principles of high resolution solution and solid state NMR, relaxation time measurements and imaging are presented. Then, the use of NMR is illustrated and reviewed in studies of biodegradation and biotransformation of soluble and solid organic matter, removal of nutrients and xenobiotics, fate of heavy metal ions, and transport processes in bioreactor systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008316031421
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  • 36
    Electronic Resource
    Electronic Resource
    Microbial degradation of polymeric coatings measured by electrochemical impedance spectroscopy (1998)
    Springer
    Biodegradation 9 (1998), S. 39-45 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; biodeterioration ; coatings ; electrochemical impedance spectroscopy ; fungi ; polyimides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper reports results of biodegradation studies of polyimide coatings exposed to a mixed fungal culture using electrochemical impedance spectroscopy (EIS). The fungal consortium was originally isolated from degraded polyimides and identified species include Aspergillus versicolor, Cladosporium cladosporioides, and a Chaetomium species. Actively growing fungi on polyimides yield distinctive EIS spectra through time, indicative of failure of the polymer integrity compared to the uninoculated controls. An initial decline in coating resistance was related to the partial ingress of water molecules and ionic species into the polymeric matrices. This was followed by further degradation of the polymers by activity of the fungi. The relationship between the changes in impedance spectra and microbial degradation of the coatings was further supported by scanning electron microscopy, showing extensive colonization of the polyimide surfaces by the fungi. Our data indicate that EIS can be a sensitive and informative technique for evaluating the biosusceptibility of polymers and coatings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008252301377
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  • 37
    Electronic Resource
    Electronic Resource
    Biodegradation of crude oil by soil microorganisms in the tropic (1998)
    Springer
    Biodegradation 9 (1998), S. 83-90 
    Details
    ISSN: 1572-9729
    Keywords: alkanes ; biodegradation ; Candida tropicalis ; crude oil ; gas chromatography ; petroleum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Five microorganisms, three bacteria and two yeasts, capable of degrading Tapis light crude oil were isolated from oil-contaminated soil in Bangkok, Thailand. Soil enrichment culture was done by inoculating the soil in mineral salt medium with 0.5% v/v Tapis crude oil as the sole carbon source. Crude oil biodegradation was measured by gas chromatography method. Five strains of pure microorganisms with petroleum degrading ability were isolated: three were bacteria and the other two were yeasts. Candida tropicalis strains 7Y and 15Y were identified as efficient oil degraders. Strain 15Y was more efficient, it was able to reduce 87.3% of the total petroleum or 99.6% of n-alkanes within the 7-day incubation period at room temperature of 25 ± 2 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008272303740
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    Electronic Resource
    Electronic Resource
    Biodegradation of N-Methylmorpholine-N-oxide (1998)
    Springer
    Biodegradation 9 (1998), S. 91-102 
    Details
    ISSN: 1572-9729
    Keywords: activated sludge ; biodegradation ; biological degradation ; lyocell fibres ; N-methylmorpholine-N-oxide ; wastewater treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract N-Methylmorpholine-N-oxide (NMMO) is capable of dissolving cellulose without any further addition of chemicals. The solution can be used to produce cellulosic staple fibres by pressing it through spinning jets into an aqueous spinning bath. Because of results from conventional biodegradation tests using non-adapted activated sludge, the solvent is generally considered being persistent. The object of the described work was to show, whether and how activated sludge can be adapted to N-methylmorpholine-N-oxide and whether it is possible to purify NMMO-containing wastewaters in conventional wastewater treatment plants. The experiments showed that the sludge can be adapted within about 15–20 days. Adapted sludge can degrade the substance itself and its most important metabolites to concentrations below their detection levels and retain this ability even during limited periods without solvent being present in the wastewater. The main requirement for a successful adaptation is a high sludge age. The degradation takes place in several steps. First, NMMO is reduced to N-methylmorpholine. The next step is a demethylation of N-methylmorpholine to morpholine. This step is crucial for the adaptation process. Once morpholine has been formed, the adaptation proceeds very quickly until none of the substances in question can be detected any longer. So the next step must be the cleavage of the morpholine ring structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008264908921
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  • 39
    Electronic Resource
    Electronic Resource
    19F NMR study on the biodegradation of fluorophenols by various Rhodococcus species (1998)
    Springer
    Biodegradation 9 (1998), S. 475-486 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; fluorophenols ; 19 F NMR ; oxidative defluorination ; Rhodococcus species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Of all NMR observable isotopes 19F is the one perhaps most convenient for studies on biodegradation of environmental pollutants. The reasons underlying this potential of 19F NMR are discussed and illustrated on the basis of a study on the biodegradation of fluorophenols by four Rhodococcus strains. The results indicate marked differences between the biodegradation pathways of fluorophenols among the various Rhodococcus species. This holds not only for the level and nature of the fluorinated biodegradation pathway intermediates that accumulate, but also for the regioselectivity of the initial hydroxylation step. Several of the Rhodococcus species contain a phenol hydroxylase that catalyses the oxidative defluorination of ortho-fluorinated di- and trifluorophenols. Furthermore, it is illustrated how the 19F NMR technique can be used as a tool in the process of identification of an accumulated unknown metabolite, in this case most likely 5-fluoromaleylacetate. Altogether, the 19F NMR technique proved valid to obtain detailed information on the microbial biodegradation pathways of fluorinated organics, but also to provide information on the specificity of enzymes generally considered unstable and, for this reason, not much studied so far.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008391906885
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  • 40
    Electronic Resource
    Electronic Resource
    Biotransformation of bezo[a]pyrene in bench scale reactor using laccase of Pycnoporus cinnabarinus (1998)
    Springer
    Biotechnology letters 20 (1998), S. 1101-1104 
    Details
    ISSN: 1573-6776
    Keywords: polycyclic aromatic hydrocarbons ; biodegradation ; filamentous fungi ; purified enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The biotransformation of benzo[a]pyrene by purified extracellular laccase of Pycnoporus cinnabarinus was investigated in bench scale reactors. The reaction required the presence of exogenous mediator ABTS. Most of 95% of the substrate was converted within 24 hours. The enzyme preparation oxidised the substrate mainly to benzo[a]pyrene 1,6- 3,6- and 6,12-quinones in a 2/1/1 ratio after 24 h incubation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005387016390
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  • 41
    Electronic Resource
    Electronic Resource
    Wet sand cultures to screen filamentous fungi for the biotransformation of polycyclic aromatic hydrocarbons (1998)
    Springer
    Biotechnology techniques 12 (1998), S. 725-728 
    Details
    ISSN: 1573-6784
    Keywords: screening ; triphasic cultures ; filamentous fungi ; biodegradation ; organic pollutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The biodegradation of phenanthrene and benzo[a]pyrene was assayed in liquid and wet sand cultures in the presence of five filamentous fungi. In the controls, 85% volatilisation of phenanthrene occurred within 28 days in liquid cultures while it was only 50% in wet sand. In the later system, remaining phenanthrene and benzo[a]pyrene amounted to 6–51 and 53–92% of their initial levels, respectively, according to the strains. Then, wet sand used as a screening tool evidenced Trametes versicolor and Cunninghamella elegans as the most efficient polycyclic aromatic hydrocarbons degraders among ten strains. © Rapid Science Ltd. 1998
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008819109005
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  • 42
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of a family of biodegradable poly(ester amide)s derived from glycine (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1271-1282 
    Details
    ISSN: 0887-624X
    Keywords: glycine ; synthesis ; biodegradation ; poly(ester amide)s ; thermal analysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of aliphatic poly(ester amide)s derived from 1,6-hexanediol, glycine, and diacids with a variable number of methylenes (from 2 to 8) have been synthesized and characterized. Infrared spectroscopy shows that the studied polymers present a unique kind of hydrogen bond that is established between their amide groups. Thermal properties as melting, glass transition, and decomposition temperatures are reported. The data indicate that all the polymers are highly crystalline. Thus, different kinds of spherulites (positive and/or negative) were obtained depending on the preparation conditions and on the polymer samples. Moreover, all the polymers crystallized from dilute diol solutions as ribbonlike crystals where a regular folding habit and a single hydrogen bond direction could be deduced. A test of enzymatic hydrolysis was employed to assess the potential biodegradability of these polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1271-1282, 1998
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    Electronic Resource
    Electronic Resource
    Artificial Wetland Performances in the Purification Efficiency of Hydrocarbon Wastewater (1998)
    Springer
    Water, air & soil pollution 104 (1998), S. 313-329 
    Details
    ISSN: 1573-2932
    Keywords: artificial wetlands ; biodegradation ; hydrocarbon ; Lemna minor ; Typha latifolia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract An artificial wetland planted with Typha latifolia was fed during a 360-day experiment with a reconstituted hydrocarbon wastewater (60 ppm, 850 L day−1). Concentrations and chemical composition were periodically monitored. The epuration efficiency was studied together with the accumulation in sediment and the bacterial development. The apparent effluent concentration was below 8 mg L−1 and the decrease in hydrocarbon concentration raised 90%. pH ranged between 6.9 and 8 and Total Suspended Solids (TSS) were below 10 mg L−1. Hydrocarbon amount accumulated in sediment was estimated to be less than 10% of the input amount. We observed a high development of aerobic heterotrophic bacteria (106 bac mL−1) and hydrocarbon-utilizing bacteria (105 bac mL−1), which probably interacted with the plants for the biodegradation of hydrocarbon (in the saturated effluent fraction, normal alkane biodegradation amounted to approximatively 80%). A comparative system with floating plants (Lemma minor), named ‘control bed’, was studied in parellel and showed lower performances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004928009345
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  • 44
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    Electronic Resource
    Extractability and Subsequent Biodegradation of PAHs from Contaminated Soil (1998)
    Springer
    Water, air & soil pollution 104 (1998), S. 285-304 
    Details
    ISSN: 1573-2932
    Keywords: biodegradation ; ethanol ; extraction ; PAHs ; polyaromatic hydrocarbons ; solvents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The biodegradation of polyaromatic hydrocarbons (PAHs) has been well documented; however, the biodegradation of PAHs in contaminated soil has proved to be problematic. Sorption of PAHs to soil over time can significantly decrease their availability for extraction much less than for biodegradation. In this study the ability of various organic solvents to extract PAHs from coal tar-contaminated soil obtained from former manufactured gas plant (MGP) sites was investigated. Solvents investigated included acetone/hexane, dichloromethane, ethanol, methanol, toluene, and water. The extraction of MGP soils with solvents was investigated using soxhlet extraction, multiple soxhlet extractions, sonication, and brief agitation at ambient temperature with a range of solvent concentrations. Of particular interest was the documentation of the recalcitrance of PAHs in weathered MGP soils to extraction and to bioremediation, as well as to demonstrate the ease with which PAHs extracted from these soils can be biodegraded. The efficiency of extraction of PAHs from MGP soils was found to be more dependent upon the choice of solvent. The environmentally-benign solvent ethanol, was shown to be equal to if not better than acetone/hexane (the EPA recommended solvent) for the extraction of PAHs from MGP soils, brief contact/agitation times (minutes) using small quantities of ethanol (2 volumes or less) can achieve nearly quantitative extraction of PAHs from MGP soils. Moreover aqueous slurries of an MGP soils experienced less than 10% biodegradation of PAHs in 14 days while in the same period about 95% biodegradation was acieved using PAHs extracted from this soil by ethanol and subsequently added to aqueous bacterial suspensions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004932110253
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  • 45
    Electronic Resource
    Electronic Resource
    Microbial Degradation of Dimethylsilanediol in Soil (1998)
    Springer
    Water, air & soil pollution 106 (1998), S. 111-122 
    Details
    ISSN: 1573-2932
    Keywords: silicone ; silanol ; environmental ; biodegradation ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Dimethylsilanediol (DMSD) is the ultimate hydrolysis product of silicone (polydimethylsiloxane = PDMS) polymer in soil. Our previous paper showed that it would volatilize from soil, and the present study investigates the importance of microbial degradation in removing DMSD from soil. DMSD (14C-labeled) was thus incubated (1 mg kg-1) for 30 wk at 25 °C in soils from a permanent grass field, a corn field, a deciduous woodland, and a pine woodland. Release of14 CO2 varied from 0.4 to 1.6% wk-1. For 3 of the soils, 14CO2 increased with higher microbial biomass, while organisms in the deciduous woodland soil were more active in degrading DMSD than organisms in the other soils. After 30 weeks, most of the remaining 14C in the soil had moved from freely available water extractable to less available acid and base extractable fractions. Similar incubations with 2% plant litter showed extensive transfer of the DMSD into the litter layer. Incubations with a microbial inhibitor showed less DMSD degradation, while cold storage of soils almost completely stopped degradation. These results suggest that microbial degradation is an important mechanism of DMSD loss from soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004933107104
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  • 46
    Electronic Resource
    Electronic Resource
    Triazine Dispersion and Distribution in the Unsaturated Zone of Drained Soils in the Brie (France) (1998)
    Springer
    Water, air & soil pollution 108 (1998), S. 129-148 
    Details
    ISSN: 1573-2932
    Keywords: biodegradation ; leaching ; soil ; triazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The purpose of this study was to investigate the fate of triazines and their metabolites in the unsaturated zone in the field conditions during a period from the spring sowings to the autumn tillages. The study was performed upon two soils treated for corn culture during the year 1992. The investigations were presented after the wet weather by subsurface drainage and surface runoff. Throughout the 6 months survey, the relative importance of the triazines is by decreasing order: atrazine 〉 simazine 〉 desethylatrazine (DEA). After the application, the herbicides were only found in the first 40 cm of the soil during the dry period of the cultivation. They were dragged towards the depth by percolation water mainly during the first water infiltrations when the drains were set in again in autumn or winter. The losses of herbicides after the cultivation cycle (october) expressed as a ratio of the initial input ranged from 40 to 73% for the atrazine and from 40 to 44% for the simazine and depended on the importance of the application amount. In autumn and winter, the losses originating in percolation were higher than those due to volatilization and/or degradation (abiotic and biodegradation), as the soil conditions were unpropicious to the formation of non-extractable residues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005021014959
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  • 47
    Electronic Resource
    Electronic Resource
    Influence of hydrodynamic conditions on naphthalene dissolution and subsequent biodegradation (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 57 (1998), S. 145-154 
    Details
    ISSN: 0006-3592
    Keywords: bioavailability ; PAH ; biodegradation ; dissolution ; hydrodynamic ; mixing ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of hydrodynamic conditions on the dissolution rate of crystalline naphthalene as a model polycyclic aromatic hydrocarbon (PAH) was studied in stirred batch reactors with varying impeller speeds. Mass transfer from naphthalene melts of different surface areas to the aqueous phase was measured and results were modeled according to the film theory. Results were generalized using dimensionless numbers (Reynolds, Schmidt, and Sherwood). In combined mass transfer and biodegradation experiments, the effect of hydrodynamic conditions on the degradation rate of naphthalene by Pseudomonas 8909N was studied. Experimental results were mathematically described using mass-transfer and microbiological models. The experiments allowed determination of mass-transfer and microbiological parameters separately in a single run. The biomass formation rate under mass transfer limited conditions, which is related to the naphthalene biodegradation rate, was correlated to the dimensionless Reynolds number, indicating increased bioavailability at increased mixing in the reactor liquid. The methodology presented in which mass transfer processes are quantified under sterile conditions followed by a biodegradation experiment can also be adapted to more complex and realistic systems, such as particulate, suspended PAH solids or soils with intrapartically sorbed contaminants when the appropriate mass-transfer equations are incorporated. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 57: 145-154, 1998.
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  • 48
    Electronic Resource
    Electronic Resource
    Surfactant-enhanced biodegradation of high molecular weight polycyclic aromatic hydrocarbons by Stenotrophomonas maltophilia (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 59 (1998), S. 482-494 
    Details
    ISSN: 0006-3592
    Keywords: polycyclic aromatic hydrocarbon ; biodegradation ; surfactants ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The objectives of this study were to isolate and evaluate microorganisms with the ability to degrade high molecular weight polycyclic aromatic hydrocarbons (PAHs) in the presence of synthetic surfactants. Stenotrophomonas maltophilia VUN 10,010, isolated from PAH-contaminated soil, utilized pyrene as a sole carbon and energy source and also degraded other high molecular weight PAHs containing up to seven benzene rings. Various synthetic surfactants were tested for their ability to improve the PAH degradation rate of strain VUN 10,010. Anionic and cationic surfactants were highly toxic to this strain, and the Tween series was used as a growth substrate. Five nonionic surfactants (Brij 35, Igepal CA-630, Triton X-100, Tergitol NP-10, and Tyloxapol) were not utilized by, and were less toxic to, strain VUN 10,010. MSR and log Km values were determined for fluoranthene, pyrene, and benzo[a]pyrene in the presence of these nonionic surfactants and their apparent solubility was increased by a minimum of 250-fold in the presence of 10 g L-1 of all surfactants. The rate of pyrene degradation by strain VUN 10,010 was enhanced by the addition of four of the nonionic surfactants (5-10 g L-1); however, 5 g L-1 Igepal CA-630 inhibited pyrene degradation and microbial growth. The specific growth rate of VUN 10,010 on pyrene was increased by 67% in the presence of 10 g L-1 Brij 35 or Tergitol NP-10. The addition of Brij 35 and Tergitol NP-10 to media containing a single high molecular weight PAH (four and five benzene rings) as the sole carbon source increased the maximum specific PAH degradation rate and decreased the lag period normally seen for PAH degradation. The addition of Tergitol NP-10 to VUN 10,010 cultures which contained a PAH mixture (three to seven benzene rings) substantially improved the overall degradation rate of each PAH and increased the specific growth rate of VUN 10,010 by 30%. Evaluation of the use of VUN 10,010 for degrading high molecular weight PAHs in leachates from surfactant-flushed, weathered, PAH-contaminated sites is warranted. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:482-494, 1998.
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  • 49
    Electronic Resource
    Electronic Resource
    Cyclodextrin effects on the ex-situ bioremediation of a chronically polychlorobiphenyl-contaminated soil (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 58 (1998), S. 345-355 
    Details
    ISSN: 0006-3592
    Keywords: cyclodextrin ; polychlorobiphenyl ; chlorobenzoic acid ; soil ; bioremediation ; biodegradation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The possibility of enhancing the intrinsic ex-situ bioremediation of a chronically polychlorinated biphenyl-contaminated soil by using cyclodextrins was studied in this work. The soil, contaminated with a large array of polychlorinated biphenyls and deriving from a dump site where it has been stored for about 10 years, was found to contain indigenous cultivable aerobic bacteria capable of utilising biphenyl and chlorobenzoic acids. The soil was amended with inorganic nutrients and biphenyl, saturated with water, and treated in aerobic batch slurry- and fixed-phase reactors. Hydroxypropyl-β-cyclodextrin and γ-cyclodextrin, added to both reactor systems at the concentration of 10 g/L at the 39th and 100th days of treatment, were found to generally enhance the depletion rate and extent of the soil polychlorobiphenyls. Despite some abiotic losses could have affected the depletion data, experimental evidence, such as the production of metabolites tentatively characterized as chlorobenzoic acids and chloride ion accumulation in the reactors, indicated that cyclodextrins significantly enhanced the biological degradation of the soil polychlorobiphenyls. This result has been ascribed to the capability of cyclodextrins of enhancing the availability of polychlorobiphenyls in the hydrophilic soil environment populated by immobilised and suspended indigenous soil microorganisms. Both cyclodextrins were metabolised by the indigenous soil microorganisms at the concentration at which they were used. Therefore, cyclodextrins, both for their capability of enhancing the biodegradation of soil polychlorobiphenyls and for their biodegradability, can have the potential of being successfully used in the bioremediation of chronically polychlorinated biphenyl-contaminated soils. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:345-355, 1998.
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  • 50
    Electronic Resource
    Electronic Resource
    Biodegradation of 1,1,1-trichloroethane by a carbon tetrachloride-degrading denitrifying consortium (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 59 (1998), S. 393-399 
    Details
    ISSN: 0006-3592
    Keywords: denitrification ; biodegradation ; kinetics ; 1,1,1-trichloroethane ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A denitrifying consortium capable of degrading carbon tetrachloride (CT) was shown to also degrade 1,1,1-trichloroethane (TCA). Fed-batch experiments demonstrated that the specific rate of TCA degradation by the consortium was comparable to the specific rate of CT degradation (approximately 0.01 L/gmol/min) and was independent of the limiting nutrient. Although previous work demonstrated that 4-50% of CT transformed by the consortium was converted to chloroform (CF), no reductive dechlorination products were detected during TCA degradation, regardless of the limiting nutrient. The lack of chlorinated TCA degradation products implies that the denitrifying consortium possesses an alternate pathway for the degradation of chlorinated solvents which does not involve reductive dechlorination. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:393-399, 1998.
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    Electronic Resource
    Effect of nonionic surfactants on naphthalene dissolution and biodegradation (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 60 (1998), S. 397-407 
    Details
    ISSN: 0006-3592
    Keywords: nonionic surfactants ; mass transfer ; bioavailability ; PAH ; biodegradation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of six nonionic surfactants, Igepal CA-720, Tergitol NPX, Triton X-100, PLE4, PLE10, and PLE23, on the dissolution rate of solid naphthalene was studied in stirred batch reactors. Results showed increased mass-transfer rates with increased surfactant concentrations up to 10 kg m-3. Dissolution experiments were adequatly described by a mechanistic mass-transfer model. Partitioning of naphthalene into the micelles and the diffusion coefficients of the micelles affected the dissolution rate most significantly. Combined dissolution and biodegradation experiments with Triton X-100 or PLE10 with naphthalene showed that the biomass-formation rate of Pseudomonas 8909N (DSM No. 11634) increased concomitantly with the mass-transfer rate under naphthalene-dissolution limited conditions up to surfactant concentrations of 6 kg m-3. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 397-407, 1998.
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    Differential synthesis of cholesterol esterase by monocyte-derived macrophages cultured on poly(ether or ester)-based poly(urethane)s (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 469-477 
    Details
    ISSN: 0021-9304
    Keywords: poly(urethane)s ; monocyte-derived macrophages ; cholesterol esterase ; biodegradation ; biostability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Monocytes adherent to implanted biomaterials differentiate into macrophages while synthesizing large amounts of degradative enzymes, including cholesterol esterase (CE), which previously has been shown to degrade poly(urethane)s. Human peripheral blood monocytes were cultured on tissue culture grade polystyrene (PS), and two model poly(urethane)s were synthesized from (1) polycaprolactone (PCL) and (2) polytetramethylene oxide (PTMO), both with 2,4-toluene diisocyanate (TDI) and ethylene diamine (ED). The increase in CE and total protein per cell were measured on days 8 and 28 in culture and normalized to the DNA content per cell. At day 8 there consistently were fewer cells remaining on the PTMO-based polymer than on the PCL-based polymer or the PS (p 〈 0.05). When comparing day 28 to day 8, there was more CE activity and protein per cell on all materials. However, there was a disproportionate synthesis of CE per mg of total protein on PS and TDI/PCL/ED whereas on PTMO there was not. Significantly, there was more protein and CE per cell on PTMO than on PS or TDI/PCL/ED (p 〈 0.05). This in vitro model system of the chronic phase of inflammation has shown that it is possible to culture monocytes for a month and assess the material surface itself as a potent activator of the differentiation into macrophages without secondary stimulation. Since CE has been shown to degrade poly(ether and ester)-based poly(urethane)s, the differential production of this enzyme relative to the total protein on different surfaces may impact on the potential long-term biostability of an implanted material. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 469-477, 1998.
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    Biodegradation in vitro and retention in the rabbit eye of crosslinked poly(1-vinyl-2-pyrrolidinone) hydrogel as a vitreous substitute (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 650-659 
    Details
    ISSN: 0021-9304
    Keywords: artificial vitreous ; 14C-labeled poly(1-vinyl-2-pyrrolidinone) ; biodegradation ; hydrogel retention ; phagocytosis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: To elucidate the relatively short retention of crosslinked poly(1-vinyl-2-pyrrolidinone) hydrogels in the eye when used as potential vitreous substitutes, a14C-labeled hydrogel was produced and subjected to both in vitro biodegradation assays and in vivo experiments. The polymer was synthesized by the free-radical copolymerization of 99% 1-vinyl-2-pyrrolidinone with 1% 14C-methyl methacrylate in the presence of ethylene glycol dimethacrylate (0.1%) as crosslinking agent. The in vitro protocol for assessing the biodegradation included the incubation of hydrogel with hydrolases (trypsin or collagenase), followed by examination of changes in its physical characteristics and by monitoring its residual radioactivity, as well as by detection of possible degradation products. Within the maximum duration of experiments (4 weeks), none of the procedures indicated biodegradation of polymer. The hydrogel was also injected into the vitreous humor of rabbits and followed up to 4 weeks. Residual radioactivity measurements of the vitreous contents indicated that 50% of the polymer was removed by the end of this period. Histopathologic examination revealed cell infiltrates of the mononuclear phagocyte system in both vitreous and retinal tissue. A possible phagocyte-mediated mechanism for the dissipation of hydrogel is discussed. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 650-659, 1998.
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    Tissue response to nano-hydroxyapatite/collagen composite implants in marrow cavity (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 540-548 
    Details
    ISSN: 0021-9304
    Keywords: nano-hydroxyapatite/collagen composite ; bone-resembling material ; bioactive ; biodegradation ; Knoop microhardness ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The tissue response to a nano-hydroxyapatite/collagen composite implanted in a marrow cavity was investigated by histology and scanning electron microscopy. A Knoop microhardness test was performed to compare the mechanical behavior of the composite and bone. The ultrastructural features of the composite, especially the carbonate-substituted hydroxyapatite with low crystallinity and nanometer size, made it a bone-resembling material. It was bioactive, as well as biodegradable. At the interface of the implant and marrow tissue, solution-mediated dissolution and giant cell mediated resorption led to the degradation of the composite. Interfacial bone formation by osteoblasts was also evident. The process of implant degradation and bone substitution was reminiscent of bone remodeling. The composite can be incorporated into bone metabolism instead of being a permanent implant. For lack of the hierarchical organization similar to that of bone, the composite exhibited an isotropic mechanical behavior. However, the resistance of the composite to localized pressure could reach the lower limit of that of the femur compacta.© 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 540-548, 1998.
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    In vitro and in vivo degradation of poly(propylene fumarate-co-ethylene glycol) hydrogels (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 312-320 
    Details
    ISSN: 0021-9304
    Keywords: cardiovascular stents ; hydrogels ; poly(ethylene glycol) ; poly(propylene fumarate) ; biodegradation ; tissue engineered implants ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The degradation of poly(propylene fumarate-co-ethylene glycol) hydrogels was examined in vitro in phosphate-buffered saline at pH 7.4 and in vivo in a subcutaneous rat model. These hydrogels have potential application as biodegradable, injectable cardiovascular stents, and, as such, their mass loss, dimensional changes, mechanical properties, morphology, and biocompatiblity over a 12-week time course were evaluated. Three formulations were fabricated: one base formulation consisting of 25% (w/w) PEG, molecular weight 4,600; one high weight percent PEG formulation with 50% (w/w) PEG; and one high molecular weight PEG formulation, molecular weight 10,500. All three formulations showed significant weight loss (between 40 and 60%) on the first day due to leaching of the uncrosslinked fraction. Further weight loss was observed only for the low weight percent PEG copolymers in the in vivo case, and a slight increase in volume was observed due to degradative swelling. The mechanical properties of the P(PF-co-EG) hydrogels decreased significantly in the first 3 weeks, showing the biphasic pattern typical of bulk degradation. In vitro, the hydrogels showed at least a 20% retention of their initial ultimate tensile stress after 3 weeks. The dynamic mechanical properties showed similar retention, with the in vivo mechanical properties differing from the in vitro properties only after 6 weeks of degradation. Differences in PEG molecular weight appeared to have little effect, but increasing the weight percent PEG decreased the rate of degradation both in vitro and in vivo. The morphology of the copolymer films, based on scanning electron microscopy observation, was not significantly different either among the three formulations or over the time course of the study, suggesting there were no macroscopic structural changes during this time period. The P(PF-co-EG) hydrogels demonstrated good initial biocompatibility, showing responses characteristic of biomaterial implants. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 312-320, 1998.
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    Assessment of an experimental bone wax polymer plus TGF-β1 implanted into calvarial defects (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 41 (1998), S. 584-592 
    Details
    ISSN: 0021-9304
    Keywords: transforming growth factor-beta1 (TGF-β1) ; wax-like polymer ; biodegradation ; biocompatibility ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The study reported describes an experimental biodegradable polymer ceramic composite with wax-like handling properties that was combined with 2.0 μg of recombinant human transforming growth factor beta (rhTGF-β1). The polymer/rhTGF-β1 combination was introduced into standard-sized calvarial defects in rabbits to evaluate biodegradability, biocompatibility, hemostasis control, and bone promotion. The experimental wound model was a standard-sized circular calvarial defect 8 mm in diameter. The experimental design included 24 skeletally mature New Zealand white rabbits divided evenly between two time periods (6 and 12 weeks) and among three experimental treatments (untreated defects and defects treated with polymer with or without rhTGF-β1). Evaluations consisted of clinical examinations, standardized radiography, radiomorphometry, as well as histology and histomorphometry. Data were analyzed by an Analysis of Variance (ANOVA) and Fisher's Protected Least Significant Difference test at each time period (level of significance p≤ 0.05). Radiomorphometry data indicated that standard-sized defects treated with the wax-like polymer alone and the polymer plus 2.0 μg of TGF-β1 were significantly more radiopaque than control sites at both 6 and 12 weeks. Histomorphometric data revealed the amount of new bone was significantly greater at 6 weeks in the polymer plus 2.0 μg of TGF-β1 and in the control group than in the polymer alone. Moreover, at 12 weeks, there was significantly more new bone in the control than in either the polymer alone or the polymer plus 2.0 μg of TGF-β1. We speculate the incomplete biodegradation of the polymer ceramic composite contributed to the radiopacity and may have retarded osseous regeneration. It is important that the bone wax-like polymer material was biocompatible and acted as a hemostatic agent. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 41, 584-592, 1998.
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    Treatment of air polluted with high concentrations of toluene and xylene in a pilot-scale biofilter (1998)
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 73 (1998), S. 183-196 
    Details
    ISSN: 0268-2575
    Keywords: biofiltration ; peat ; biodegradation ; toluene ; xylene ; inhibition ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Air biofiltration is now under active consideration for the removal of the volatile organic compounds from air polluted streams. In order to investigate the performance of this newly developed technology, a biofiltration pilot unit was operated for a continuous period of 8 months. The biofilter column was packed with commercially conditioned peat. At start-up, the filter bed was inoculated with four species of microorganisms. The resulting biofilter was fed with air contaminated with toluene, xylene or a mixture of toluene and xylene. The maximum elimination capacities attained were 165 g m-3 h-1 for toluene, 66 g m-3 h-1 for xylene and 115 g m-3 h-1 for the mixture of toluene and xylene. These specific performances exceed the values published in the technical and commercial literature for similar processes. Xylene isomers were degraded in decreasing order of reactivity, m-xylene, p-xylene, o-xylene. In the case of air polluted with a toluene and xylene mixture, it was noticed that the metabolism of toluene biodegradation was inhibited by the presence of xylene. Characterization of the biofilm microbial populations after several weeks of operation showed that the dominant strains among the isolated culturable strains from the biofilm, even if different from the initially inoculated strains, had at least one physiological property favoring degradation of aromatic organic rings. The performance of the biofilter was found to be dependent on the temperature of the filter media and the pressure drop through the bed. Finally, a steady state mathematical model was tested in order to theoretically describe the experimental results. This model is used to illustrate the operating diffusion and reaction regimes at steady state for the case of each pollutant. © 1998 Society of Chemical Industry
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    Microbial removal of alkanes from dilute gaseous waste streams: Mathematical modeling of advanced bioreactor systems (1998)
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 72 (1998), S. 93-98 
    Details
    ISSN: 0268-2575
    Keywords: VOC ; biodegradation ; alkanes ; trickle-bed ; mass transfer ; kinetics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many industries generate volatile organic compounds (VOCs) in dilute streams which must be removed before being released into the environment. Mathematical models for biological filters which can remediate waste streams are useful both as predictive tools and as a means to better understand the fundamental processes involved. Optimization of the system also necessitates a better understanding of the mechanisms by which biofilters work and can be approached through modeling and maximizing appropriate conditions for removal. In a trickle-bed bioreactor, VOCs (n-pentane and isobutane) were passed over a biofilm-coated packing which degraded the VOCs. Bacterial growth was controlled via liquid nutrient-limited media trickled through the reactor. Results from this trickle-bed system were analyzed by applying a simple mathematical model to accurately describe the processes which are believed to play important roles. The model was based on a two-step process: mass transfer in which the VOCs diffuse into the liquid biofilm, and kinetics by which VOCs are degraded by the biofilm. Modeling results revealed that both kinetic and mass transfer resistances were significant under typical operating conditions.
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    A mixed finite element/finite volume approach for solving biodegradation transport in groundwater (1998)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 533-556 
    Details
    ISSN: 0271-2091
    Keywords: mixed finite elements ; finite volumes ; groundwater flow and transport ; biodegradation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical model for the simulation of flow and transport of organic compounds undergoing bacterial oxygen- and nitrate-based respiration is presented. General assumptions regarding microbial population, bacteria metabolism and effects of oxygen, nitrogen and nutrient concentration on organic substrate rate of consumption are briefly described. The numerical solution techniques for solving both the flow and the transport are presented. The saturated flow equation is discretized using a high-order mixed finite element scheme, which provides a highly accurate estimation of the velocity field. The transport equation for a sorbing porous medium is approximated using a finite volume scheme enclosing an upwind TVD shock-capturing technique for capturing concentration-unsteady steep fronts. The performance and capabilities of the present approach in a bio-remediation context are assessed by considering a set of test problems. The reliability of the numerical results concerning solution accuracy and the computational efficiency in terms of cost and memory requirements are also estimated. © 1998 John Wiley & Sons, Ltd.
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    Indirect bioremediation: biodegradation of hydrocarbons on a commercial sorbent (1997)
    Springer
    Biodegradation 8 (1997), S. 15-19 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; crude oil ; hexadecane ; phenanthrene ; sorbent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Urea-formaldehyde polymer is currently used as asorbent for containment and clean up of hydrocarbons. The aerobic biodegradability of this polymer andhydrocarbons sorbed to the polymer were tested. Soilmicroorganisms readily grew on the polymer, and twoorganisms, a bacterium and a fungus, capable of growthon the polymer were isolated. However, biodegradationof the polymer was very slow and possibly incomplete. Biodegradation of the polymer was evident as a changein appearance of the polymer, but disappearance of thepolymer was not detectable in liquid culturesincubated for six months or soil cultures incubatedfor one month. Destruction of the polymer by soilmicroorganisms at ambient temperature does not appearto be practical. Degradation of 14C-labeledhexadecane and phenanthrene mixed with crude oil inliquid cultures inoculated with soil microorganismswas used as an estimate of general hydrocarbondegradation. When nitrogen was not limiting, therates of hexadecane and phenanthrene degradation werethe same, whether those hydrocarbons were sorbed tothe polymer or not sorbed. When nitrogen waslimiting, the polymer stimulated the rate ofhexadecane degradation but not the rate ofphenanthrene degradation. The polymer may stimulatehexadecane degradation by serving as a source ofnitrogen. However, optimal degradation of sorbedhydrocarbons requires nitrogen addition. The resultssuggest that it may be feasible to decontaminate spentpolymer by biodegradation of sorbed hydrocarbons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008285705628
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    Biodegradation of the chlorophenoxy herbicide (R)-(+)-mecoprop by Alcaligenes denitrificans (1997)
    Springer
    Biodegradation 8 (1997), S. 43-52 
    Details
    ISSN: 1572-9729
    Keywords: Alcaligenes denitrificans ; biodegradation ; chloroaromatic ; mecoprop (R)-(+)-2(2-methyl-4-chlorophenoxy)propionic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An Alcaligenes denitrificans strain capable of utilizing theherbicide (R)-(+)-2(2-methyl-4-chlorophenoxy)propionicacid (mecoprop) as a sole carbon source was isolated fromsoil and cultured in liquid medium. Crude cell extracts of thebacterium were utilized in spectrophotometric assays toelucidate a biochemical pathway for degradation ofmecoprop. Results indicated a reaction sequence analogousto the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D).GC-MS analysis provided direct evidence for thebiotransformation of mecoprop to the transient metabolite4-chloro-2-methylphenol (MCP). No NADPH-dependentactivity was observed during this reaction. Pyruvate wasverified as the second product derived from the aliphatic sidechain of mecoprop. MCP was subsequently transformed to asubstituted catechol by an NADPH-dependentmonooxygenase. When grown on mecoprop, A.denitrificans was adapted to oxidize catechol and its 4- and3-methylated derivatives indicating the broad substratespecificity of catechol dioxygenase. The microorganism wasdemonstrated to adopt the ortho mechanism of aromaticcleavage which resulted in the formation of2-methyl-4-carboxymethylene but-2-en-4-olide, a reactionintermediate of the β-ketoadipate pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008262901202
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    Biodegradation of benzene, toluene and naphthalene in soil-water slurry microcosms (1997)
    Springer
    Biodegradation 8 (1997), S. 167-175 
    Details
    ISSN: 1572-9729
    Keywords: benzene ; bioavailability ; biodegradation ; naphthalene ; sorption ; toluene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Aerobic biodegradation of benzene, toluene andnaphthalene was studied in pre-equilibrated soil-waterslurry microcosms. The experiments were designed tosimulate biodegradation at waste sites where sorptionreaches equilibrium before biodegradation becomesimportant. Rates of biodegradation were reduced by thepresence of soil. For example, nearly completenaphthalene biodegradation (1.28 mg/L) by indigenoussoil bacteria occurred within 60 hours in aqueoussolution (soil-free) while it took two weeks todegrade the same amount in the presence of 0.47 kgsoil/L of water. The rate of biodegradation wasobserved to decrease with increasing organic compoundhydrophobicity, soil/water ratio, soil particle size,and soil organic carbon content. These resultsclearly indicate that the rate of biodegradation isaffected by both the extent and rate of sorption. Further analysis suggests that mass transfer couldcontrol the performance of in situ bioremediation forhighly hydrophobic organic contaminants which exhibita large extent of sorption and slow rate ofdesorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008259511282
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    Terpene-utilizing isolates and their relevance to enhanced biotransformation of polychlorinated biphenyls in soil (1997)
    Springer
    Biodegradation 8 (1997), S. 153-158 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; PCB ; Aroclor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Orange peels, eucalyptus leaves, pine needles and ivy leaves were addedseparately to soil spiked with Aroclor 1242 (100 mgkg-1.Polychorinated biphenyls (PCBs) disappeared after six months in all theamended soils, but not in unamended soils. Although biphenyl was not addedto any of the soils, all four amended soils had much higher levels(108/g) of biphenyl-utilizing bacteria than the unamendedcontrol (103/g). Ten random isolates obtained from these soilswere identified as coryneform bacteria. Five isolates, that were distinctlydifferent, were studied further with respect to growth on pure terpenes andmetabolism of PCBs. The most effective strains were Cellulomonas sp. T109and R. rhodochrous T100, which metabolized 83% and 80% ofAroclor 1242, respectively, during a six day period of growth on cymene andlimonene, respectively. The bphA gene, cloned as a 2.8 Kb Sa/I fragment ofpAW6194 from cbpA (Walia et al. 1990) hybridized to total DNA of allcoryneform isolates, and to the well-established PCB degrader Rhodococcusgloberulus. In contrast, a 5 Kb XhoI-SmaI fragment of the bphA gene(Furukawa & Miyazaki 1986) did not show any homology to the genomic DNAof any of the isolates or to R. globerulus, but did hybridize to two otherwell-known PCB degraders Pseudomonas sp. LB400, and Alcaligenes eutrophusH850. The data presented herein indicate that terpenes may be naturalsubstrates for biphenyl-degrading bacteria and may enhance substantialtransformation of Aroclor 1242.
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    URL: http://dx.doi.org/10.1023/A:1008255218432
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    Implementation of natural attenuation at a JP-4 jet fuel release after active remediation (1997)
    Springer
    Biodegradation 8 (1997), S. 265-273 
    Details
    ISSN: 1572-9729
    Keywords: natural attenuation ; biodegradation ; hydrocarbon ; groundwater ; BTEX ; MTBE ; site characterization ; fate and transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract After eighteen months of active remediation at a JP-4 jet-fuel spill, aresidual of unremediated hydrocarbon remained. Further site characterizationwas conducted to evaluate the contribution of natural attenuation to controlexposure to hazards associated with the residual contamination in thesubsurface. Activities included the detailed characterization ofground-water flow through the spill; the distribution of fuel contaminantsin groundwater; and the analysis of soluble electron acceptors moving intothe spill from upgradient. These activities allowed a rigorous evaluation ofthe transport of contaminants from the spill to the receptor of groundwater,the Pasquotank River. The transport of dissolved contaminants of concern,that is benzene, toluene, ethyl benzene, xylene isomers (BTEX) andmethyl-tertiary-butyl ether (MTBE), into the river from the source area wascontrolled by equilibrium dissolution from the fuel spill to the adjacentgroundwater, diffusion in groundwater from the spill to permeable layers inthe aquifer, and advective transport in the permeable layers. The estimatedyearly loading of BTEX compounds and MTBE into the receptor was trivial evenwithout considering biological degradation. The biodegradation ofhydrocarbon dissolved in groundwater through aerobic respiration,denitrification, sulfate reduction, and iron reduction was estimated fromchanges in ground-water chemistry along the flow path. The concentrations oftarget components in permanent monitoring wells continue to decline overtime. Long term monitoring will ensure that the plume is under control, andno further active remediation is required.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008212127604
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    Ring cleavage of sulfur heterocycles: how does it happen? (1997)
    Springer
    Biodegradation 8 (1997), S. 297-311 
    Details
    ISSN: 1572-9729
    Keywords: benzothiophenes ; biodegradation ; biodesulfurization ; dibenzothiophenes ; thiacycloalkanes ; thiophenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sulfur heterocycles are common constituents ofpetroleum and liquids derived from coal, and they arefound in some secondary metabolites of microorganismsand plants. They exist primarily as saturated ringsand thiophenes. There are two major objectives drivinginvestigations of the microbial metabolism oforganosulfur compounds. One is the quest to develop aprocess for biodesulfurization of fossil fuels, andthe other is to understand the fates of organosulfurcompounds in petroleum- or creosote-contaminatedenvironments which is important in assessingbioremediation processes. For these processes to besuccessful, cleavage of different types of sulfurheterocyclic rings is paramount. This paper reviewsthe evidence for microbial ring cleavage of a varietyof organosulfur compounds and discusses the fewwell-studied cases which have shown that the C–S bondis most susceptible to breakage leading to disruptionof the ring. In most cases, the introduction of one ormore oxygen atom(s) onto the adjacent C atom and/oronto the S atom weakens the C–S bond, facilitating itscleavage. Although much is known about the thiophenering cleavage in dibenzothiophene, there is still agreat deal to be learned about the cleavage of othersulfur heterocycles.
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    URL: http://dx.doi.org/10.1023/A:1008283207090
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    Enhancement of biodegradation of phenol and a nongrowth substrate 4-chlorophenol by medium augmentation with conventional carbon sources (1997)
    Springer
    Biodegradation 8 (1997), S. 329-338 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; cometabolism ; nongrowth substrate ; conventional carbon sources ; inhibition ; pH regulation ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The enhancement of biodegradation of phenol and4-chlorophenol (4-cp) as a cometabolised compound byPseudomonas putida ATCC 49451 was accomplishedby augmenting the medium with conventional carbonsources such as sodium glutamate and glucose. Comparedwith phenol as the sole carbon source, the addition of1 gl-1 sodium glutamate increased the toxicitytolerance of cells toward 4-cp and significantlyimproved the biodegradation rates of both phenol and4-cp even when the initial concentration of 4-cp wasas high as 200 mgl-1. On the other hand,supplementation of glucose caused a significant dropin the medium pH from 7.2 to 4.3 resulting in areduction of degradation rate, leaving a considerableamount of 4-cp undegraded when the initialconcentration of 4-cp was higher than 100 mgl-1.By regulating the pH of the medium, however,enhancement of degradation rates of phenol and 4-cp inthe presence of glucose was achieved with aconcomitant complete degradation of phenol and 4-cp.
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    URL: http://dx.doi.org/10.1023/A:1008267607634
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    Biodegradation of 4-nitrophenol by indigenous microbial populations in Everglades soils (1997)
    Springer
    Biodegradation 8 (1997), S. 349-356 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; bioremediation ; acclimation ; Everglades ; mineralization ; nitrophenol ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Everglades in South Florida are a unique ecologicalsystem. As a result of the widespread use of pesticides andherbicides in agricultural areas upstream from these wetlands,there is a serious potential for pollution problems in theEverglades. The purpose of this study was to evaluate theability of indigenous microbial populations to degradexenobiotic organic compounds introduced by agricultural andother activities. Such biodegradation may facilitate theremediation of contaminated soils and water in the Everglades.The model compound selected in this study is 4-nitrophenol, achemical commonly used in the manufacture of pesticides. Themineralization of 4-nitrophenol at various concentrations wasstudied in soils collected from the Everglades. Atconcentrations of 10 and 100 µg/g soil, considerablemineralization occurred within a week. At a higherconcentration, i.e., 10 mg/g soil, however, no mineralizationof 4-nitrophenol occurred over a 4-month period; such a highconcentration apparently produced an inhibitory effect. Therate and extent of 4-nitrophenol mineralization was enhancedon inoculation with previously isolated nitrophenol-degradingmicroorganisms. The maximum mineralization extent measured,however, was less than 30% suggesting conversion to biomassand/or unidentified intermediate products. These resultsindicate the potential for natural mechanisms to mitigate theadverse effects of xenobiotic pollutants in a complex systemsuch as the Everglades.
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    URL: http://dx.doi.org/10.1023/A:1008285717595
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    Biodegradation of alkylpyridines by bacteria isolated from a polluted subsurface (1997)
    Springer
    Biodegradation 8 (1997), S. 357-361 
    Details
    ISSN: 1572-9729
    Keywords: alkylpyridine ; subsurface bacteria ; biodegradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ten bacterial strains were isolated fromalkylpyridine polluted sediments 7.6 m below thesurface. These strains were able to degrade 11different alkylpyridine isomers. Degradation ratesdepended on number and position of the alkyl group. Isomers with an alkyl group at position 3 were moreresistant to microbial attack. Of the 10 strains, 6isolates were selected for detailed study. Theseisolates mineralized the isomers to CO2,NH4 +, and biomass. All strains weregram-negative rods with a strict aerobic metabolism. Characterization of physiological and biochemicalproperties revealed similarity between strains. Eeachstrain however, had a limited substrate range whichenabled it to degrade no more than 2 to 3 compounds ofthe 14 alkylpyridine isomers tested. Examination ofthe genetic variability among cultures with therandomly amplified polymorphic DNA technique revealedhigh levels of genomic DNA polymorphism. The highestsimilarity between 2 strains (0.653) was observedbetween 2-picoline and 3-picoline degrading cultures. The molecular basis of the differences in substratespecificity is under investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008278631418
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    A Model for diffusion controlled bioavailability of crude oil components (1997)
    Springer
    Biodegradation 8 (1997), S. 287-296 
    Details
    ISSN: 1572-9729
    Keywords: asphaltene ; bioavailability ; biodegradation ; crude oil ; diffusivity ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Crude oil is a complex mixture ofseveral different structural classes of compoundsincluding alkanes, aromatics, heterocyclic polarcompounds, and asphaltenes. The rate and extent ofmicrobial degradation of crude oil depends on theinteraction between the physical and biochemicalproperties of the biodegradable compounds and theirinteractions with the non-biodegradable fraction. Inthis study we have systematically altered theconcentration of non-biodegradable material in thecrude oil and analyzed its impact on transport of thebiodegradable components of crude oil to themicroorganisms. We have also developed a mathematicalmodel that explains and accounts for the dependence ofbiodegradation of crude oil through a putativebioavailability parameter. Experimental resultsindicate that as the asphaltene concentration in oilincreases, the maximum oxygen uptake in respirometersdecreases. The mathematically fitted bioavailabilityparameter of degradable components of oil alsodecreases as the asphaltene concentration increases.
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    URL: http://dx.doi.org/10.1023/A:1008293024768
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    Biodegradation of dissolved jet fuel in chemostat by a mixed bacterial culture isolated from a heavily polluted site (1997)
    Springer
    Biodegradation 8 (1997), S. 363-369 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; BTEX ; kerosene ; residual concentration ; volatilisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A mixed bacterial culture capable of biodegrading of jet fuel was isolated from a heavily polluted site in Tapa, Estonia. Residual concentrations of pollutants in the chemostat culture were determined. The total residual concentrations of dissolved jet fuel in culture medium were 0.42 and 2.1 μg l-1 at the dilution rates 0.1 and 0.17 h-1respectively. Benzene, toluene, ethylbenzene, and xylenes were completely degraded and thus not detected in culture broth (detection limit 0.1 μg l-1)at the dilution rates 0.1 and 0.17 h-1. The values of apparent substrate saturation constant(KSapp) in multisubstrate growth conditions were estimated from the experimental data. The residual concentrations satisfy the regulations in the Republic of Estonia for petroleum hydrocarbons (0.00 mg l-1 – ‘very good’). Results obtained indicate that use of the biodegradation could be sufficient for the treatment of polluted with kerosene-type jet fuel groundwater up to the acceptable quality.
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    URL: http://dx.doi.org/10.1023/A:1008251605107
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    Prevalence of monochloroacetate degrading genotypes among soil isolates of Pseudomonas (1997)
    Springer
    Biodegradation 8 (1997), S. 371-377 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; dehalogenase ; monochloroacetate ; Pseudomonas sp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study reports the isolation of Pseudomonas sp strains with monochloroacetate (MCA) degradation function, from uncontaminated soil, and the use of Southern blot hybridization technique to detect MCA degrading catabolic genes and their divergence. Based on their capacity to remove Cl- from MCA in a minimal medium containing 185 ppm Cl-, the strains were classified into three groups: poor degraders (Cl- release between 0–15 ppm), medium degraders (Cl- release between 16–30 ppm), and high degraders (Cl- release between 31–45 ppm).We have applied a gene probe assay for determining the diversity of MCA degradative genotypes of 61 strains. Two different gene probes, dehCI and dehCII were used in Southern blot hybridization assays. Majority of the DNA samples that produced signals on the membrane blots (18 out of 24)hybridized with only dehCI DNA probe, while 6strains hybridized with only dehCII probe. On the other hand, 37 isolates did not hybridize to either of the gene probes used. The results indicated the high specificity of the DNA hybridization method and the divergence of metabolic functions and/or genotypes among the native MCA-degrading Pseudomonas sp. populations in the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008275128329
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    Microbiological aspects of surfactant use for biological soil remediation (1997)
    Springer
    Biodegradation 8 (1997), S. 401-417 
    Details
    ISSN: 1572-9729
    Keywords: bioavailability ; biodegradation ; bioremediation ; mass transfer ; soil sanitation ; surfactants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Biodegradation of hydrophobic organic compounds in polluted soil is a process involving interactions among soil particles, pollutants, water, and micro-organisms. Surface-active agents or surfactants are compounds that may affect these interactions, and the use of these compounds may be a means of overcoming the problem of limited bioavailability of hydrophobic organic pollutants in biological soil remediation. The effects of surfactants on the physiology of micro-organisms range from inhibition of growth due to surfactant toxicity to stimulation of growth caused by the use of surfactants as a co-substrate. The most important effect of surfactants on the interactions among soil and pollutant is stimulation of mass transport of the pollutant from the soil to the aqueous phase. This can be caused by three different mechanisms: emulsification of liquid pollutant, micellar solubilisation, and facilitated transport. The importance of these mechanisms with respect to the effect of surfactants on bioavailability is reviewed for hydrophobic organic pollutants present in different physical states. The complexity of the effect of surfactants on pollutant bioavailability is reflected by the results in the literature, which range from stimulation to inhibition of desorption and biodegradation of polluting compounds. No general trends can be found in these results. Therefore, more research is necessary to make the application of surfactants a standard tool in biological soil remediation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008291130109
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    The effect of inorganic and organic supplements on the microbial degradation of phenanthrene and pyrene in soils (1997)
    Springer
    Biodegradation 8 (1997), S. 1-13 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; PAH ; phenanthrene ; pyrene ; bioremediation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of several bioremediation stimulants, including potentialmetabolism pathway inducers, inorganic/organic nutrients, and surfactants onthe metabolism of phenanthrene and pyrene, as well as the populationdynamics of PAH degrading microorganisms was examined in five soils withdiffering background PAH concentrations, exposure histories and physicalproperties. Most of the supplements either had no significant effect ordecreased the mineralization of [14C]-phenanthrene and[14C]-pyrene in soil slurry microcosms. The effect of aparticular supplement, however, was often not uniform within or acrosssoils. Decreased mineralization of [14C]-phenanthrene and[14C]-pyrene was usually due to either preferential use of thesupplement as carbon source and/or stimulation of non-PAH degradingmicroorganisms. Many of the supplements increased populations ofheterotrophic microorganisms, as measured by plate counts, but did notincrease populations of phenanthrene degrading microorganisms, as measuredby the [14C]-PAH mineralization MPN analysis or cellularincorporation of [14C]-PAH. These results suggest that the PAHdegrading community at each site may be unique in their response tomaterials added in an attempt to stimulate PAH degradation. Thecharacteristics of the site, including exposure history, soil type, andtemporal variation may all influence their response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008258720649
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    Sucrose diacrylate: A unique chemically and biologically degradable crosslinker for polymeric hydrogels (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2221-2229 
    Details
    ISSN: 0887-624X
    Keywords: biodegradation ; hydrogels ; crosslinking agent ; sucrose diacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of degradable hydrogels based on different vinyl monomers such as acrylamide, sucrose-1′-acrylate, and acrylic acid were synthesized using sucrose-6,1′-diacrylate (SDA) as a crosslinking agent. SDA was prepared by enzymatic transesterification of vinyl acrylate with sucrose in pyridine. Base catalyzed hydrolysis of SDA in aqueous solution was studied as a function of pH. As expected, hydrolysis of SDA was faster at higher pHs such that poly(acrylamide), poly(sucrose 1′-acrylate), and poly(acrylic acid) hydrogels underwent substantial degradation at and above pH 7, 9, and 13, respectively. The degradation was characterized by changes in the swelling ratios of the hydrogels indicating breakage of the crosslinking agent. Degradation of the hydrogels at their chemically stable pHs was studied in presence of enzymes. Enzymes, including pepsin and a fungal Lipase, were able to degrade the poly(acrylamide) hydrogel at pH 4 and 5, respectively. Poly(acrylic acid) hydrogel was degraded in presence of a fungal protease at pH 7.8. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2221-2229, 1997
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    Crosslinking of hyaluronic acid with glutaraldehyde (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 3553-3559 
    Details
    ISSN: 0887-624X
    Keywords: hyaluronic acid ; crosslinking ; glutaraldehyde ; biodegradation ; IR spectra ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hyaluronic acid (HA) was chemically crosslinked with glutaraldehyde (GA) to produce water-insoluble films having low water contents when brought into contact with water. The crosslinking reaction was performed using uncrosslinked HA films in acetone-water mixtures. This method could produce water-insoluble HA films with water contents as low as 60 wt % when subjected to swelling with phosphate-buffered saline of pH 7.4 at 37°C. This 60 wt % water content was lower than any values for HA ever reported. There was an optimal HCl concentration around 0.01N for the HA crosslinking with GA in acetone - water mixtures. To get information on the crosslinking mechanism, alginic acid, which possesses hydroxyl and carboxyl groups in one molecule, similar to HA, and poly(vinyl alcohol) (PVA) and amylopectin, which possess only hydroxyl groups, were subjected to crosslinking with GA. PVA and amylopectin were also found to become water-insoluble after reaction with GA. On the basis of the infrared spectra of these crosslinked films, it was concluded that intermolecular formation of hemiacetal bonds with GA between the hydroxyl groups belonging to different HA molecules led to crosslinking. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3553-3559, 1997
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    The effect of temperature on eicosane substrate uptake modes by a marine bacterium Pseudomonas nautica strain 617: relationship with the biochemical content of cells and supernatants (1997)
    Springer
    World journal of microbiology and biotechnology 13 (1997), S. 587-590 
    Details
    ISSN: 1573-0972
    Keywords: Adherence ; biodegradation ; biosurfactants ; marine bacterium ; n -alkane ; temperature effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Three hydrocarbon uptake modes (adherence, emulsification and solubilization) were identified and quantified in cells and supernatants of a mesophilic marine bacterium Pseudomonas nautica strain 617 grown on eicosane. The adherence capacity was related to the enrichment of cells with wax esters and glycolipids. The emulsifying activity was related to the presence of extracellular biosurfactants composed of proteins, carbohydrates and lipids (35:63:2). The intensity of substrate uptake modes was sensitive to temperatures currently found in the original environment of P. nautica (16°C, 20°C and 32°C). When temperature decreased, a significant increase in adherence and emulsifying activity was observed in relation to biochemical changes, whereas solubilizing activity decreased. The marine bacterium was able to degrade 53–59% eicosane at the end of exponential growth after 13, 5 and 3 days incubation at 16°C, 20°C and 32°C respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018581829320
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    Biodegradation of phenol and cresol isomer mixtures by Arthrobacter (1997)
    Springer
    World journal of microbiology and biotechnology 13 (1997), S. 659-663 
    Details
    ISSN: 1573-0972
    Keywords: Arthrobacter ; biodegradation ; competitive inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The Arthrobacter species can degrade phenol, o-cresol and p-cresol much faster (as reflected in high specific growth rates) than other microbes which are reported to degrade toxic compounds. In mixtures, phenol and p-cresol mutually inhibited each other; the inhibition constants show that phenol degradation is strongly inhibited in the presence of p-cresol rather than reverse. o-Cresol enhanced phenol degradation marginally but o-cresol degradation was not affected by the presence of phenol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018518904730
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    Determination of carbon dioxide evolution rate using on-line gas analysis during dynamic biodegradation experiments (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 53 (1997), S. 243-252 
    Details
    ISSN: 0006-3592
    Keywords: carbon dioxide evolution rate ; mass transfer ; modeling ; biodegradation ; pH ; kinetics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Respirometry is a precious tool for determining the activity of microbial populations. The measurement of oxygen uptake rate is commonly used but cannot be applied in anoxic or anaerobic conditions or for insoluble substrate. Carbon dioxide production can be measured accurately by gas balance techniques, especially with an on-line infrared analyzer. Unfortunately, in dynamic systems, and hence in the case of short-term batch experiments, chemical and physical transfer limitations for carbon dioxide can be sufficient to make the observed carbon dioxide evolution rate (OCER) deduced from direct gas analysis very different from the biological carbon dioxide evolution rate (CER).To take these transfer phenomena into account and calculate the real CER, a mathematical model based on mass balance equations is proposed. In this work, the chemical equilibrium involving carbon dioxide and the measured pH evolution of the liquid medium are considered. The mass transfer from the liquid to the gas phase is described, and the response time of the analysis system is evaluated.Global mass transfer coefficients (KLa) for carbon dioxide and oxygen are determined and compared to one another, improving the choice of hydrodynamic hypotheses. The equations presented are found to give good predictions of the disturbance of gaseous responses during pH changes.Finally, the mathematical model developed associated with a laboratory-scale reactor, is used successfully to determine the CER in nonstationary conditions, during batch experiments performed with microorganisms coming from an activated sludge system. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 243-252, 1997.
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    Biodegradation of paint stripper solvents in a modified gas lift loop bioreactor (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 55 (1997), S. 163-169 
    Details
    ISSN: 0006-3592
    Keywords: bioreactor ; paint stripper solvents ; biodegradation ; model ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Paint stripping wastes generated during the decontamination and decommissioning of former nuclear facilities contain paint stripping organics (dichloromethane, 2-propanol, and methanol) and bulk materials containing paint pigments. It is desirable to degrade the organic residues as part of an integrated chemical-biological treatment system. We have developed a modified gas lift loop bioreactor employing a defined consortium of Rhodococcus rhodochrous strain OFS and Hyphomicrobium sp. DM-2 that degrades paint stripper organics. Mass transfer coefficients and kinetic constants for biodegradation in the system were determined. It was found that transfer of organic substrates from surrogate waste into the air and further into the liquid medium in the bioreactor were rapid processes, occurring within minutes. Monod kinetics was employed to model the biodegradation of paint stripping organics. Analysis of the bioreactor process was accomplished with BIOLAB, a mathematical code that simulates coupled mass transfer and biodegradation processes. This code was used to fit experimental data to Monod kinetics and to determine kinetic parameters. The BIOLAB code was also employed to compare activities in the bioreactor of individual microbial cultures to the activities of combined cultures in the bioreactor. This code is of benefit for further optimization and scale-up of the bioreactor for treatment of paint stripping and other volatile organic wastes in bulk materials. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 163-169, 1997.
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  • 80
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    Cometabolism of chlorinated solvents by nitrifying bacteria: Kinetics, substrate interactions, toxicity effects, and bacterial response (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 54 (1997), S. 520-534 
    Details
    ISSN: 0006-3592
    Keywords: nitrifying bacteria ; Nitrosomonas europaea ; cometabolism ; ammonia monooxygenase ; biodegradation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pure cultures of ammonia-oxidizing bacteria, Nitrosomonas europaea, were exposed to trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), chloroform (CF), 1,2-dichloroethane (1,2-DCA), or carbon tetrachloride (CT), in the presence of ammonia, in a quasi-steady-state bioreactor. Estimates of enzyme kinetics constants, solvent inactivation constants, and culture recovery constants were obtained by simultaneously fitting three model curves to experimental data using nonlinear optimization techniques and an enzyme kinetics model, referred to as the inhibition, inactivation, and recovery (IIR) model, that accounts for inhibition of ammonia oxidation by the solvent, enzyme inactivation by solvent product toxicity, and respondent synthesis of new enzyme (recovery). Results showed relative enzyme affinities for ammonia monooxygenase (AMO) of 1,1-DCE ≈ TCE 〉 CT 〉 NH3 〉 CF 〉 1,2-DCA. Relative maximum specific substrate transformation rates were NH3 〉 1,2-DCA 〉 CF 〉 TCE ≈ 1,1-DCE 〉 CT (=0). The TCE, CF, and 1,1-DCE inactivated the cells, with 1,1-DCE being about three times more potent than TCE or CF. Under the conditions of these experiments, inactivating injuries caused by TCE and 1,1-DCE appeared limited primarily to the AMO enzyme, but injuries caused by CF appeared to be more generalized. The CT was not oxidized by N. europaea while 1,2-DCA was oxidized quite readily and showed no inactivation effects. Recovery capabilities were demonstrated with all solvents except CF. A method for estimating protein yield, the relationship between the transformation capacity model and the IIR model, and a condition necessary for sustainable cometabolic treatment of inactivating substrates are presented. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 520-534, 1997.
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    Toxicity and biodegradation of formaldehyde in anaerobic methanogenic culture (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 55 (1997), S. 727-736 
    Details
    ISSN: 0006-3592
    Keywords: acetate ; anaerobic ; biodegradation ; formaldehyde ; methanogenic ; toxicity ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Formaldehyde is present in several industrial wastewaters including petrochemical wastes. In this study, the toxicity and degradability of formaldehyde in anaerobic systems were investigated. Formaldehyde showed severe toxicity to an acetate enrichment methanogenic culture. As low as 10 mg/L (0.33 mM) of formaldehyde in the reactor completely inhibited acetate utilization. Formaldehyde, however, was degraded while acetate utilization was inhibited. Degradation of formaldehyde (Initial concentration ≤30 mg/L) followed Monod model with a rate constant, k, of 0.35-0.46 d-1. At higher initial concentrations (≥60 mg/L), formaldehyde degradation was inhibited and partial degradation was possible. The initial formaldehyde to biomass ratio, S0/X0, was useful to predict the degradation potential of high formaldehyde concentrations in batch systems. When S0/X0 ≤ 0.1, formaldehyde was completely degraded with initial concentration of up to 95 mg/L; when S0/X0 ≥ 0.29, formaldehyde at higher than 60 mg/L was only partially degraded. The inhibition of formaldehyde degradation in batch systems could be avoided by repeated additions of low concentrations of formaldehyde (up to 30 mg/L). Chemostats (14-day retention time) showed degradation of 74 mg/L-d (1110 mg/L) of influent formaldehyde with a removal capacity of 164 mg/g VSS-day. A spike of 30 mg/L (final concentration in the chemostat) formaldehyde to the chemostat caused only a small increase in effluent acetate concentration for 3 days. But a spike of 60 mg/L (final concentration in the chemostat) formaldehyde to the chemostat resulted in a dramatic increase in acetate concentration in the effluent. The results also showed that the acetate enrichment culture was not acclimated to formaldehyde even after 226 days. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 727-736, 1997.
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    Biodegradation and plant protection from the herbicide 2,4-D by plant-microbial associations in cotton production systems (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 54 (1997), S. 513-519 
    Details
    ISSN: 0006-3592
    Keywords: plant-microbial associations ; 2,4-D ; biodegradation ; plant protection ; Dolichos lablab ; cotton ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A significant “biosafening” protection of plants from the effect of 2,4-D in plant-microbial associations has been demonstrated in this study. The 2,4-D-degrading plasmid, pJP4 was transferred into Rhizobium sp. CB1024, which nodulates Dolichos lablab, and Azospirillum brasilense Sp7 carrying a nifA-lacZ gene marker, which can colonize cotton roots. Both transconjugants degraded 2,4-D in pure culture via cometabolism up to 50 μg mL-1. When the transconjugants were inoculated onto Dolichos lablab and cotton, respectively, such plants were resistant to this herbicide when the nutrient solution was treated with 2,4-D up to 10 μg mL-1 for Dolichos lablab and 0.5 μg mL-1 for cotton. Plants inoculated with wild-type strains were dead (Dolichos lablab) or dying (cotton). Because cotton is more sensitive to herbicides, only incomplete protection of plants was achieved with the transconjugant. Improving the effect of colonization of Azospirillum on cotton roots may be critical for a complete degradation and plant protection. The transconjugant of Rhizobium sp. CB1024 was still able to nodulate Dolichos lablab, N2-fixing activity was only slightly affected. Other pesticide-degrading capacities may also be inserted into those plant-associated bacterial strains for the degradation of these chemicals by plant-microbial associations. Whether such systems will be successful when applied in the field with competition from other bacteria is being examined. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 513-519, 1997.
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    Kinetic characterization of mass transfer limited biodegradation of a low water soluble gas in batch experiments - Necessity for multiresponse fitting (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 55 (1997), S. 511-519 
    Details
    ISSN: 0006-3592
    Keywords: ethene ; kinetics ; biodegradation ; mass transfer ; multiresponse fitting ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method was developed to characterize the kinetics of biodegradation of low water soluble gaseous compounds in batch experiments. The degradation of ethene by resting Mycobacterium E3 cells was used as a model system. The batch degradation data were recorded as the progress curve (i.e., the time course of the ethene concentration in the headspace of the batch vessel). The recorded progress curves, however, suffered gas:liquid mass transfer limitation. A new multiresponse fitting method had to be developed to allow unequivocal identification of both the affinity coefficient, Kaff, and the gas:liquid mass transfer coefficient, Kla, in the batch vessel from the mass transfer limited data. Simulation showed that the Kaff estimate obtained is influenced by the dimensionless (volumetric basis) ethene gas:liquid partitioning coefficient (H). In the fitting procedure, Monod, Teissier, and Blackman biokinetics were evaluated for characterization of the ethene biodegradation process. The fits obtained reflected the superiority of the Blackman biokinetic function. Overall, it appears that resting Mycobacterium E3 cells metabolizing ethene at 24°C have, using Blackman biokinetics, a maximum specific degradation rate, vmax, of 10.2 nmol C2H4 mg-1 CDW min-1, and an affinity coefficient, Kaff.g, expressed in equilibrium gas concentration units, of 61.9 ppm, when H is assumed equal to 8.309. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 511-519, 1997.
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    Crosslinking of hyaluronic acid with water-soluble carbodiimide (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 37 (1997), S. 243-251 
    Details
    ISSN: 0021-9304
    Keywords: hyaluronic acid ; crosslinking ; water-soluble carbodiimide ; biodegradation ; IR spectra ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Hyaluronic acid (HA) was chemically crosslinked with a water-soluble carbodiimide (WSC) to produce low-water-content films when brought into contact with water. The crosslinking reaction was performed in two different ways; one was by using HA films and the other by casting HA solutions. Both methods produced water-insoluble HA films. The lowest water content of the crosslinked HA films subjected to swelling with water was 60 wt% at 37°C, which was lower than any reported values. Infrared spectra of the crosslinked films suggested that intermolecular formation of ester bonds between the hydroxyl and carboxyl groups belonging to different polysaccharide molecules led to crosslinking. For comparison, pectin which possesses hydroxyl and carboxyl groups in one molecule, similar to HA, was subjected to crosslinking with WSC. The finding on pectin also supported ester formation between different polysaccharide molecules. The crosslinking of HA film with WSC in the presence of L-lysine methyl ester prolonged the in vivo degradation of HA film, probably because of amide bond formation as the crosslink. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 243-251, 1997.
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    Effect of alternative crosslinking techniques on the enzymatic degradation of bovine pericardia and their calcification (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 35 (1997), S. 357-369 
    Details
    ISSN: 0021-9304
    Keywords: biodegradation ; tissue crosslinking calcification ; polyethylene glycol ; chemical treatments ; enzyme degradation ; SEM ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The in vitro calcification and enzymatic degradation of bovine pericardia (BP) after a series of surface treatments were studied as a function of exposure time. The degradation of these treated surfaces was monitored by scanning electron micrography and tensile strength measurements. Polyethylene glycol-(PEG) grafted BP and glutaraldehyde- (GA) treated BPs retained maximum stability in collagenase digestion compared with SDS-treated BP. The ability of α chymotrypsin, bromelain, esterase, trypsin, and collagenase to modulate the degradation of SDS-, GA-, PEG-, Carbodiimide-, and glycidylether-treated BPs also was investigated. Incubation of various enzymes to these crosslinked pericardia variably reduced the tensile strength of these tissues. It is conceivable that chemical treatments of pericardial tissues might have altered their physical and chemical configuration and the subsequent degradation properties. In vitro calcification studies showed a substantial reduction in the calcification profile of PEG-grafted bovine pericardia compared to other treated tissues. Furthermore, the biocompatibility aspects of pericardial tissues were established by platelet adhesion and octane contact angle. In conclusion, it seems that the surface modification of bovine pericardia via GA-PEG grafting may provide new ways of controlling biodegradation and calcification. © 1997 John Wiley & Sons, Inc., J Biomed Mater Res, 35, 357-369, 1997.
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    Biodegradation of a poly(ester)urea-urethane by cholesterol esterase: Isolation and identification of principal biodegradation products (1997)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 36 (1997), S. 407-417 
    Details
    ISSN: 0021-9304
    Keywords: biodegradation ; polyurethane ; enzyme ; high-performance liquid chromatography ; mass spectrometry ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Synthesized poly(ester)urea-urethanes with 14C-labeled toluene diisocyanate or 14C-labeled chain extender ethylene diamine were incubated with cholesterol esterase in a phosphate buffer solution at 37°C. A number of biodegradation products, generated at the level of 2.8 μg/cm2 of polymer surface area, were isolated from this simulated physiologic system. Individual products were obtained by separation with reversed-phase high-performance liquid chromatography. The two different radiolabels were used to assist in the identification of degradation products from hard- and soft-segment domains. Approximately 20 degradation products were isolated; however, toluene diamine (TDA) was not detected from the chromatographic separation. Two principal products were identified by tandem mass spectrometry. Both products are TDA derivatives (secondary aromatic diamine) substituted with end units of the polyester segment at N and N′ positions of TDA. The absence of free TDA suggests that there could be a stabilization of urethane and urea linkages within the toluene diisocyanate (TDI) segments of the polyurethanes. For TDI-synthesized polymers, this finding raises awareness to the potential biological importance of degradation products other than TDA, particularly to their interaction with surrounding cells. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 36, 407-417, 1997.
    Additional Material: 8 Ill.
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  • 87
    Electronic Resource
    Electronic Resource
    Decolourisation of Orange II by a Wood-Rotting Fungus (1997)
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 69 (1997), S. 289-296 
    Details
    ISSN: 0268-2575
    Keywords: biodegradation ; decolourisation ; azo dye ; white rot fungi ; effluent treatment ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: --The decolourisation of Orange II by a wood-rotting fungus has been studied. It was found that Fungus F29 could effectively decolourise Orange II especially when grown as pelleted mycelia under agitated conditions. Many factors affecting the decolourisation process in nitrogen-limited media (NLM) were studied, including: concentration of glucose, NH4+, Mn(II) and veratryl alcohol; initial pH; amount of mycelium; mycelial age; Orange II concentration; temperature. Results showed that the media containing Orange II at 1000 mg dm-3 (or higher) could be decolourised by 98% of the initial colour (A480 nm) in 2 days, in most conditions tested, and that the mycelia could be repeatedly reused. © 1997 SCI.
    Additional Material: 7 Ill.
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  • 88
    Electronic Resource
    Electronic Resource
    Enhancement of phenol biodegradation by south magnetic field exposure (1997)
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 70 (1997), S. 299-303 
    Details
    ISSN: 0268-2575
    Keywords: oxidation ; biodegradation ; magnetic field ; immobilized bacteria ; water treatment ; activated sludge ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: --Microbial pellets in the presence of south pole magnetic fields demonstrate enhanced oxidation of phenol. Earlier work at 0·49 tesla indicates qualitatively that a unipolar north magnetic field inhibits and a south magnetic field accelerates phenol oxidation rates of an alginate immobilized, mixed bacterial culture bioreactor. This work demonstrates further enhancement by exposure during phenol oxidation at 0·15 and 0·35 tesla, as well as by exposure during acclimation of the free microorganisms prior to immobilization. The enhancement of biodegradation is a function of magnetic field strength and time of exposure. Enhancement is greatest at 0·15 tesla and indicates the existence of an optimum south magnetic field strength ©1997 SCI
    Additional Material: 4 Ill.
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  • 89
    Electronic Resource
    Electronic Resource
    Preparation conditions and swelling equilibria of biodegradable hydrogels prepared from microbial poly(γ-glutamic acid) and poly(ε-lysine) (1996)
    Springer
    Journal of polymers and the environment 4 (1996), S. 123-129 
    Details
    ISSN: 1572-8900
    Keywords: Poly(γ-glutamic acid) ; poly(ε-lysine) ; hydrogel ; biodegradation ; enzymatic degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Biodegradable hydrogels prepared by γ-irradiation from microbial poly(amino acid)s are reviewed. pH-sensitive hydrogels were prepared by means of γ-irradiation of poly(γ-glutamic acid) (PGA) produced byBacillus subtilis IFO3335 and poly(ε-lysine) (PL) produced byStreptomyces albulus in aqueous solutions. The preparation conditions, swelling equilibria, hydrolytic degradation, and enzymatic degradation of these hydrogels were studied. A hydrogel with a wide variety of swelling behaviors has been produced by γ-irradiation from a mixture solution of PGA and PL.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02074873
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  • 90
    Electronic Resource
    Electronic Resource
    Properties and biodegradability of chain-extended copoly(succinic anhydride/ethylene oxide) (1996)
    Springer
    Journal of polymers and the environment 4 (1996), S. 225-233 
    Details
    ISSN: 1572-8900
    Keywords: Copolyesterether ; succinic anhydride ; chain-extension reaction ; biodegradation ; activated sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Chain-extension reactions were carried out using titanium-iso-propoxide (TIP) as a catalyst for a series of polyesters or copolyesterethers with low molecular weights (M n =1500–10,000) synthesized by the ring-opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO). The copolymers having aM n from 25,000 to 50,000 of different properties were obtained. Both the melting point (T m ) and the fusion heat (δH), which indicate the crystallinity of the copolymers, rose with an increase in SA content in the copolymers. Semitransparent films were prepared by compression molding of the copolymers. The biodegradation of the copolymer films was evaluated by enzymatic hydrolysis by lipases and by an aerobic gas evolution test in standard activated sludge. The hydrolyzability of these copolymers by three kinds of lipases was affected by their copolymer composition SA/EO, form, andM n . The copolyesterether (SA/EO=43/57,M n =48,900) was more easily biodegraded by standard activated sludge compared to the polyester (SA/EO=47/53,M n =36,300).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02070691
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  • 91
    Electronic Resource
    Electronic Resource
    Evaluation of biodegradability of poly(ε-caprolactone)/poly(ethylene terephthalate) blends (1996)
    Springer
    Journal of polymers and the environment 4 (1996), S. 37-50 
    Details
    ISSN: 1572-8900
    Keywords: Poly(ethylene terephthalate) ; poly(ε-caprolactone) ; blends ; biodegradation ; composting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The results of an investigation aimed at evaluation of the biodegradability of blends of poly(ε-caprolactone) (PCL) with poly(ethylene terephthalate) (PET) as the major component are reported. Specimens of the blends, as melt extruded films and/or powders, were submitted to degradation tests under different environmental conditions including full-scale composting, soil burial, bench-scale accelerated aerobic degradation, and exposure to axenic cultures and esterolytic enzymes. Indications have been gained that blending in the melt gives rise to insertion of PCL segments in the PET chain. Copolymers thus attained acted as macromolecular compatibilizers, allowing for a complete miscibility of PCL and PET. The biodegradation detected on the blend samples was, however, well below the values expected from chemical composition and behavior of individual homopolymers under the same environmental conditions. The presence of PET as the major component in PET/PCL blends apparently reduces the propensity of PCL to be degraded, at least in the investigated composition range. The degradation data collected under different environmental conditions indicate that the full-scale composting system is the most efficient among the tested degradation procedures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02083881
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  • 92
    Electronic Resource
    Electronic Resource
    Anaerobic microbial degradation of poly (3-hydroxyalkanoates) with various terminal electron acceptors (1996)
    Springer
    Journal of polymers and the environment 4 (1996), S. 91-102 
    Details
    ISSN: 1572-8900
    Keywords: Poly (3-hydroxyalkanoates) ; poly (3-hydroxybutyrate) ; poly (3-hydroxybutyrate-co-3-hydroxyvalerate) ; biodegradation ; nitrate reduction ; iron reduction ; sulfate reduction ; methanogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The microbial degradation of poly (3-hydroxyalkanoates) (PHAs) under anaerobic conditions with various terminal electron acceptors was examined. Nitrate-reducing consortia were established using activated sludge, and PHAs were shown to be biodegradable under these conditions. A positive correlation between carbon dioxide production and nitrate reduction was demonstrated. Nitrous oxide accumulated as the main N-containing product of nitrate reduction. The amount of PHAs in activated sludge cultures decreased approximately 20% within 40 days of incubation. Attempts were made to establish iron- and sulfate-reducing consortia from spring water, yet it could not be demonstrated that the mixed cultures were capable of degrading PHAs. Pure cultures of iron- and sulfate-reducing bacteria could not utilize PHAs as sole carbon sources. Methanogenic environments sampled included pond sediment and rumen fluid. PHAs were fermented to methane and carbon dioxide after 10 weeks by a sediment consortium, with 43 to 57% of the substrate carbon transformed to methane. Although it could not be demonstrated that PHAs were biodegraded by a rumen fluid consortium, a facultative anaerobic bacterium, identified as aStaphylococcus sp., that could grow on PHAs was isolated from rumen fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02074870
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  • 93
    Electronic Resource
    Electronic Resource
    The influence of degree of substitution on blend miscibility and biodegradation of cellulose acetate blends (1996)
    Springer
    Journal of polymers and the environment 4 (1996), S. 179-195 
    Details
    ISSN: 1572-8900
    Keywords: Cellulose acetate ; composting ; radiochemical labeling ; biodegradation ; blend miscibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this account, we report our findings on blends of cellulose acetate having a degree of substitution (DS) of 2.49 (CA2.5) with a cellulose acetate having a DS of 2.06 (CA2.0). This blend system was examined over the composition range of 0–100% CA2.0 employing both solvent casting of films (no plasticizer) and thermal processing (melt-compressed films and injection molding) using poly(ethylene glycol) as a common plasticizer. All thermally processed blends were optically clear and showed no loss in optical quality after storage for several months. Thermal analysis and measurement of physical properties indicate that blends in the middle composition range are partially miscible, while those at the ends of the composition range are miscible. We suggest that the miscibility of these cellulose acetate blends is influenced primarily by the monomer composition of the copolymers. Bench-scale simulated municipal composting confirmed the biodestructability of these blends and indicated that incorporation of a plasticizer accelerated the composting rates of the blends.In vitro aerobic biodegradation testing involving radiochemical labeling conclusively demonstrated that both the lower DS CA2.0 and the plasticizer significantly enhanced the biodegradation of the more highly substituted CA2.5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02067452
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  • 94
    Electronic Resource
    Electronic Resource
    The anaerobic biodegradation of diethanolamine by a nitrate reducing bacterium (1996)
    Springer
    Biodegradation 7 (1996), S. 183-189 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; diethanolamine ; ethanolamines ; nitrate reduction ; amine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The ability of bacterial cultures to degrade diethanolamine under anoxic conditions with nitrate as an electron acceptor was investigated. A mixed culture capable of anaerobic degradation of diethanolamine was obtained from river sediments by enrichment culture. From this a single bacterial strain was isolated which could use diethanolamine, monoethanolamine, triethanolamine and N-methyl diethanolamine as its sole carbon and energy sources either aerobically or anaerobically. Growth on diethanolamine was faster in the absence of oxygen. The accumulation of possible metabolites in the culture medium was determined as was the ability to grow on certain putative intermediates in the degradation of diethanolamine. A possible pathway for the degradation of ethanolamines by this organism is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00058178
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  • 95
    Electronic Resource
    Electronic Resource
    Biodegradation of rubber particles in soil (1996)
    Springer
    Biodegradation 7 (1996), S. 329-333 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; modelling ; rubber ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The biodegradation of rubber particles in rubber-soil mixtures at different rubber contents was monitored by the carbon dioxide production. The cumulative carbon dioxide production was modelled according to a two parameter exponential function. The model provides an excellent fit (R2〉0.98) for the observed data. The two parameters yield a reliable estimate of the half-life for the process observed, but estimation of the true half-life of rubber in soil will need more research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00115746
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  • 96
    Electronic Resource
    Electronic Resource
    Anaerobic degradation of phthalic acid esters during digestion of municipal solid waste under landfilling conditions (1996)
    Springer
    Biodegradation 7 (1996), S. 345-352 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; methane formation ; phthalic acid esters ; landfills ; bioremediation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Anaerobic microorganisms in municipal solid waste samples from laboratory-scale landfill reactors and a pilot-plant biogas digestor were investigated with the aim of assessing their ability to transform four commercially used phthalic acid esters (PAEs) and phthalic acid (PA). The PAEs studied were diethyl phthalate (DEP), butylbenzyl phthalate (BBP), dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP). No biological transformation of DEHP could be detected in any of the experiments. Together with waste samples from the simulated landfilling conditions, the PAEs (except DEHP) were hydrolytically transformed to their corresponding monoesters. These accumulated as end products, and in most cases they were not further degraded. During incubation with waste from the biogas digestor, the PAEs (except DEHP) were completely degraded to methane and carbon dioxide. The influence of the landfill development phase on the transformations was investigated utilizing PA and DEP as model substances. We found that during both the intense and stable methanogenic (but not the acidogenic) phases, the microoganisms in the samples had the potential to transform PA. A shorter lag phase was observed for the PA transformation in the samples from the stable methanogenic phase as compared with earlier phases. This indicates an increased capacity to degrade PA during the aging phases of the municipal solid waste in landfills. No enhancement of the DEP transformation could be observed as conditions in the methanogenic landfill model changed over a year's time. The results indicate that microorganisms developing in a methanogenic landfill environment have a substantially lower potential to degrade PAEs compared with those developing in a biogas reactor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00115748
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  • 97
    Electronic Resource
    Electronic Resource
    Isolation from coastal sea water and characterization of bacterial strains involved in non-ionic surfactant degradation (1996)
    Springer
    Biodegradation 7 (1996), S. 369-375 
    Details
    ISSN: 1572-9729
    Keywords: bacteria ; biodegradation ; marine environment ; non-ionic surfactant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A bacterial community degrading branched alkylphenol ethoxylate (APE) was selected from coastal sea water intermittently polluted by urban sewage. This community degraded more than 99% of a standard surfactant, TRITON X 100, but I.R. analysis of the remaining compound showed the accumulation of APE2 (alkylphenol with a two units length ethoxylated chain) which seemed very recalcitrant to further biodegradation. Twenty-five strains were isolated from this community, essentially Gram negative and were related to Pseudomonas, Oceanospirillum or Deleya genera. Among these strains, only four were able to degrade APE9–10 (TRITON X 100). They were related to the Pseudomonas genus and were of marine origin. Pure cultures performed with these strains on TRITON X 100 gave APE5 and APE4 as end products. These products were further degraded to APE2 by two other strains unable to degrade the initial surfactant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00056420
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  • 98
    Electronic Resource
    Electronic Resource
    Aerobic degradation of polychlorinated biphenyls by Alcaligenes sp. JB1: metabolites and enzymes (1996)
    Springer
    Biodegradation 7 (1996), S. 435-443 
    Details
    ISSN: 1572-9729
    Keywords: aerobic ; biodegradation ; enzymes ; induction ; polychlorinated biphenyls ; resting-cell assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In contrast to the degradation of penta-and hexachlorobiphenyls in chemostat cultures, the metabolism of PCBs by Alcaligenes sp. JB1 was shown to be restricted to PCBs with up to four chlorine substituents in resting-cell assays. Among these, the PCB congeners containing ortho chlorine substituents on both phenyl rings were found to be least degraded. Monochloro-benzoates and dichlorobenzoates were detected as metabolites. Resting cell assays with chlorobenzoates showed that JB1 could metabolize all three monochlorobenzoates and dichlorobenzoates containing only meta and para chlorine substituents, but not dichlorobenzoates possessing an ortho chlorine substituent. In enzyme activity assays, meta cleaving 2,3-dihydroxybiphenyl 1,2-dioxygenase and catechol 2,3-dioxygenase activities were constitutive, whereas benzoate dioxygenase and ortho cleaving catechol 1,2-dioxygenase activities were induced by their substrates. No activity was found for pyrocatechase II, the enzyme that is specific for chlorocatechols. The data suggest that complete mineralization of PCBs with three or more chlorine substituents by Alcaligenes sp. JB1 is unlikely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00115290
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  • 99
    Electronic Resource
    Electronic Resource
    Assessing mineralization rates of petroleum hydrocarbons in soils in relation to environmental factors and experimental scale (1996)
    Springer
    Biodegradation 7 (1996), S. 487-500 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; bioremediation ; mathematical modeling ; soil respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Mineralization rates of non-volatile petroleum hydrocarbons (HCs) in five different oil-contaminated soils with initial HC contents ranging from 0.1 to 13 g kg-1 are estimated as a function of environmental factors. The aim of the study is threefold, (i) to study the relevance of environmental factors that may influence the mineralization rate, (ii) to compare mineralization rates estimated in two experiments at different scales, after standardizing them to environmental reference conditions, (iii) to evaluate the CO2 production rate as a measure for the mineralization rate of HCs. Experiments were performed at laboratory scale (30–50 cm3 soil volume) in closed-jars under constant environmental conditions and in lysimeters (0.81 m3 soil volume) under dynamic climatic and hydrological conditions. A biodegradation model, coupled to transport models for soil heat, water, and gas dynamics is employed for data interpretation. The transport models are used to simulate the environmental conditions that influence the mineralization rate in the non-steady lysimeter experiments. The results show that temperature, O2 concentration and HC content have an effect on the mineralization rates. Water content could not be identified as a direct governing environmental factor. However, an indirect effect of water content is that it influences the effective gas diffusion coefficient in soils. The CO2 production rate seems to be a good quantity to express the mineralization rate of HCs for HC contents〉1 g kg-1. Measured CO2 production rates standardized to reference conditions are similar for the two different experimental scales. This demonstrates that the usage of biodegradation rates obtained in the laboratory to predict the biodegradation rates under field conditions is sound, as long as the differences in environmental conditions have been taken into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00115295
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  • 100
    Electronic Resource
    Electronic Resource
    Degradation of 4-aminobenzenesulfonate by a two-species bacterial coculture (1996)
    Springer
    Biodegradation 7 (1996), S. 223-229 
    Details
    ISSN: 1572-9729
    Keywords: Agrobacterium radiobacter ; 4-aminobenzenesulfonate ; biodegradation ; cross-feeding ; Hydrogenophaga palleronii ; mixed culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mutualistic interactions in a 4-aminobenzenesulfonate (sulfanilate) degrading mixed bacterial culture were studied. This coculture consisted of Hydrogenophaga palleronii strain S1 and Agrobacterium radiobacter strain S2. In this coculture only strain S1 desaminated sulfanilate to catechol-4-sulfonate, which did not accumulate in the medium but served as growth substrate for strain S2. During growth in batch culture with sulfanilate as sole source of carbon, energy, nitrogen and sulfur, the relative cell numbers (colony forming units) of both strains were almost constant. None of the strains reached a cell number which was more than threefold higher than the cell number of the second strain. A mineral medium with sulfanilate was inoculated with different relative cell numbers of both strains (relative number of colony forming units S1:S2 2200:1 to 1:500). In all cases, growth was found and the proportion of both strains moved towards an about equal value of about 3:1 (strain S1:strain S2). In contrast to the coculture, strain S1 did not grow in a mineral medium in axenic culture with 4-aminobenzenesulfonate or any other simple organic compound tested. A sterile culture supernatant from strain S2 enabled strain S1 to grow with 4-aminobenzenesulfonate. The same growth promoting effect was found after the addition of a combination of 4-aminobenzoate, biotin and vitamin B12. Strain S1 grew with 4-aminobenzenesulfonate plus the three vitamins with about the same growth rate as the mixed culture in a mineral medium. When (resting) cells of strain S1 were incubated in a pure mineral medium with sulfanilate, up to 30% of the oxidized sulfanilate accumulated as catechol-4-sulfonate in the culture medium. In contrast, only minor amounts of catechol-4-sulfonate accumulated when strain S1 was grown with 4ABS in the presence of the vitamins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00058181
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