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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymers and the environment 4 (1996), S. 123-129 
    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.
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  • 2
    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).
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  • 3
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymers and the environment 4 (1996), S. 91-102 
    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
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  • 5
    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.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 7 (1996), S. 183-189 
    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.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 7 (1996), S. 329-333 
    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.
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  • 8
    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.
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  • 9
    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.
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  • 10
    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.
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  • 11
    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.
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  • 12
    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.
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  • 13
    ISSN: 1572-9729
    Keywords: biodegradation ; diesel fuel ; marine & particulate organic carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Diesel fuel pollution in coastal waters, resulting from recreational boating and commercial shipping operations, is common and can adversely affect marine biota. The purpose of this study was to examine the effect of additions of particulate organic carbon (POC) in the form of naturally-occurring marsh grass (Spartina alterniflora), inorganic nutrients (nitrogen and phosphorus), inert particles, and dissolved organic carbon (DOC) on diesel fuel biodegradation and to attempt to formulate an effective bioremedial treatment for small diesel fuel spills in marine waters. Various combinations of treatments were added to water samples from a coastal marina to stimulate diesel fuel biodegradation. Diesel fuel was added in concentrations approximating those found in a spill and biodegradation of straight chain aliphatic constituents was estimated by measuring mineralization of 14C hexadecane added to diesel fuel. All treatments that included POC showed stimulation of biodegradation. However, the addition of inert particles (glass fiber filters and nylon screening) caused no stimulation of biodegradation. The addition of nitrogen and phosphorus alone did not result in stimulation of biodegradation, but nitrogen and Spartina (although not phosphorus and Spartina) did result in stimulation above that of Spartina alone. Maximum biodegradation rates were obtained by the addition of the Spartina POC, ammonium, and phosphate. The addition of mannitol, a labile DOC source with POC and phosphate resulted in a decrease in diesel fuel biodegradation as compared to POC and phosphate alone. The seasonal pattern of diesel fuel biodegradation showed a maximum in the summer and a minimum in the winter. Therefore, of the treatments tested, the most effective for bioremediation of diesel fuel in marine waters is the addition of POC, nitrogen, and phosphorus.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 7 (1996), S. 73-81 
    ISSN: 1572-9729
    Keywords: diesel oil ; biodegradation ; CSTR ; kinetics
    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 batch culture diesel oil was degraded rapidly, with a maximum growth rate (for a consortium of microorganisms) of 0.55 h-1. The corresponding yield Y SX was 0.1 Cmol/Cmol. In a continuous stirred tank reactor the maximum dilution rate was about 0.25 h-1, with a yield of 0.3 Cmol/Cmol. With a residence time of 1 day 82% of the influent oil was degraded. In the batch reactor, of the mixture of linear and branched alkanes the linear alkanes were degraded fastest and with the highest yield. Only after most of the linear alkanes had disappeared were the branched alkanes consumed. In a CSTR a large part of the branched alkanes was not degraded.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 7 (1996), S. 249-255 
    ISSN: 1572-9729
    Keywords: biodegradation ; O-demethylation ; metabolism ; 4-nitroanisole ; 4-nitrophenol
    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 Rhodococcus strains, R. opacus strain AS2 and R. erythropolis strain AS3, that were able to use 4-nitroanisole as the sole source of carbon and energy, were isolated from environmental samples. The first step of the degradation involved the O-demethylation of 4-nitroanisole to 4-nitrophenol which accumulated transiently in the medium during growth. Oxygen uptake experiments indicated the transformation of 4-nitrophenol to 4-nitrocatechol and 1,2,4-trihydroxybenzene prior to ring cleavage and then subsequent mineralization. The nitro group was removed as nitrite, which accumulated in the medium in stoichiometric amounts. In R. opacus strain AS2 small amounts of hydroquinone were produced by a side reaction, but were not further degraded.
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  • 16
    ISSN: 1572-9729
    Keywords: atrazine ; bacteria ; biodegradation ; mineralization ; sorption
    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 purpose of the present study was to assess atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) mineralization by indigenous microbial communities and to investigate constraints associated with atrazine biodegradation in environmental samples collected from surface soil and subsurface zones at an agricultural site in Ohio. Atrazine mineralization in soil and sediment samples was monitored as 14CO2 evolution in biometers which were amended with 14C-labeled atrazine. Variables of interest were the position of the label ([U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine), incubation temperature (25°C and 10°C), inoculation with a previously characterized atrazine-mineralizing bacterial isolate (M91-3), and the effect of sterilization prior to inoculation. In uninoculated biometers, mineralization rate constants declined with increasing sample depth. First-order mineralization rate constants were somewhat lower for [2-14C-ethyl]-atrazine when compared to those of [U-14C-ring]-atrazine. Moreover, the total amount of 14CO2 released was less with [2-14C-ethyl]-atrazine. Mineralization at 10°C was slow and linear. In inoculated biometers, less 14CO2 was released in [2-14C-ethyl]-atrazine experiments as compared with [U-14C-ring]-atrazine probably as a result of assimilatory incorporation of 14C into biomass. The mineralization rate constants (k) and overall extents of mineralization (P max ) were higher in biometers that were not sterilized prior to inoculation, suggesting that the native microbial populations in the sediments were contributing to the overall release of 14CO2 from [U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine. A positive correlation between k and aqueous phase atrazine concentrations (C eq ) in the biometers was observed at 25°C, suggesting that sorption of atrazine influenced mineralization rates. The sorption effect on atrazine mineralization was greatly diminished at 10°C. It was concluded that sorption can limit biodegradation rates of weakly-sorbing solutes at high solid-to-solution ratios and at ambient surface temperatures if an active degrading population is present. Under vadose zone and subsurface aquifer conditions, however, low temperatures and the lack of degrading organisms are likely to be primary factors limiting the biodegradation of atrazine.
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  • 17
    ISSN: 1432-1327
    Keywords: Key words Metalloenzymes ; Nuclear magnetic resonance ; Aromatic compounds ; biodegradation ; hydration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  Water proton T 1 –1 measurements at magnetic fields between 0.01 and 50 MHz [nuclear magnetic relaxation dispersion (NMRD) measurements] have been performed on solutions of phthalate dioxygenase (PDO) reconstituted at the catalytic iron site with copper(II) or manganese(II). The data show evidence of a weakly coordinated water molecule in CuPDO; in the presence of the substrate, phthalate, this water appears to become even less tightly bound, and an additional tightly coordinated water can be detected. In PDO reconstituted with manganese, one tightly coordinated water is detected in the presence and in the absence of phthalate. An attempt is made to reconcile these data with low-temperature near-IR magnetic circular dichroism and X-ray absorption data, which show that PDO reconstituted with iron or cobalt is six-coordinate in the absence of substrate and five-coordinate in the presence of substrate.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 16 (1996), S. 79-101 
    ISSN: 1476-5535
    Keywords: alginate ; bacteria ; biodegradation ; bioremediation ; κ-carrageenan ; encapsulation ; immobilization ; microorganisms ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Immobilized microbial cells have been used extensively in various industrial and scientific endeavours. However, immobilized cells have not been used widely for environmental applications. This review examines many of the scientific and technical aspects involved in using immobilized microbial cells in environmental applications, with a particular focus on cells encapsulated in biopolymer gels. Some advantages and limitations of using immobilized cells in bioreactor studies are also discussed.
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  • 19
    ISSN: 1476-5535
    Keywords: bioventing ; biodegradation ; respirometry ; inoculation ; nutrients ; diesel oil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effects of bioventing, nutrient addition and inoculation with an oil-degrading bacterium on biodegradation of diesel oil in unsaturated soil were investigated. A mesocosm system was constructed consisting of six soil compartments each containing 6 m3 of naturally contaminated soil mixed 1∶1 with silica sand, resulting in a diesel oil content of approximately 2000 mg kg−1. Biodegradation was monitored over 112 days by determining the actual diesel oil content of the soil and by respirometric tests. The best agreement between calculations of degradation rates based upon the two methods was in July, when venting in combination with nutrient addition resulted in degradation rates of 23 mg kg−1 day−1 based on actual oil concentration in the soil and 33 mg kg−1 day−1 calculated from respirometric data. In September, these rates decreased to 9 and 1.4 mg kg−1 day−1, and in October the degradation rates were 5 and 0.7 mg kg−1 day−1 based upon the two methods. The average ambient temperature during the respirometric tests was 14,10 and 2°C in July, September and October, respectively. The combination of venting and nutrient addition resulted in an average residual oil content of the soil of 380 mg kg−1. Neither venting alone nor inoculation enhanced oil degradation. The respiratory quotient averaged 0.40. The oil composition changed following degradation resulting in the unresolved complex mixture constituting up to 96% of the total oil content at the end of the experimental period.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 16 (1996), S. 325-329 
    ISSN: 1476-5535
    Keywords: biodegradation ; evaporation ; polychlorinated biphenyls ; PCB ; Alcaligenes xylosoxidans ; Pseudomonas stutzeri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract During microbial degradation of PCBs in a liquid medium, two processes influence the PCB concentration in the medium simultaneously: biodegradation and evaporation. The physical loss of PCB due to evaporation frequently causes false positive results in biodegradation experiments. Therefore, if only PCBs are monitored, the determination of the PCB concentration in both liquid and gaseous phases is necessary for a correct appraisal of biodegradation. The kinetics of PCB evaporation and biodegradation were monitored and described by a simple mathematical model. The evaporation and biodegradation rate constants for individual PCB congeners were determined for PCB degradation in liquid medium byPseudomonas stutzeri andAlcaligenes xylosoxidans, both isolated from a longterm PCB-contaminated soil.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 16 (1996), S. 301-304 
    ISSN: 1476-5535
    Keywords: phthalate esters ; biodegradation ; Rhodococcus ; Aureobacterium ; Flavobacterium ; Fusarium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Bacterial and fungal strains were isolated from enrichment cultures using diethylphthalate, diethylterephthalate, or ethylene glycol dibenzoate as sole carbon sources.Aureobacterium, Flavobacterium, andMicrococcus species were isolated from diethylphthalate enrichments;Rhodococcus andXanthomonas species were isolated from diethylterephthalate enrichments;Rhodococcus andFusarium species were isolated from ethylene glycol dibenzoate enrichments.
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  • 22
    ISSN: 1476-5535
    Keywords: lupanine ; quinolizidine alkaloids ; BIOLOG ; bacterial isolation ; biodegradation ; lupin debittering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Seven Gram-negative bacterial strains, capable of using lupanine, the predominant quinolizidine alkaloid in white lupin, as sole carbon and energy source, were isolated from soil in whichLupinus albus andL. luteus had been grown. A metabolic profile system (BIOLOG) identified only three of the seven isolates, two asXanthomonas oryzae pvoryzae E and one asGluconobacter cerinus. The maximum specific growth rates of the seven isolates when incubated at 27°C in a medium containing as sole carbon source 2 g L−1 of lupanine, ranged from 0.05 to 0.13 h−1 and the concentration of dry biomass at the stationary phase ranged from 0.7 to 1.1 g L−1. Unidentified strains IST20B and IST40D exhibited the highest maximum specific growth rates (0.13h−1), removed 99% of the initial lupanine after 30 h of incubation, and the dry biomass yields did not exceed 0.4 g per g lupanine consumed. Strain IST20B is of potential use forL. albus debittering because, after 32 h growth in aqueous extracts ofL. albus, 85% of initial alkaloids were removed while the concentration of soluble protein was only reduced by 8%.
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  • 23
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    Journal of sol gel science and technology 7 (1996), S. 77-79 
    ISSN: 1573-4846
    Keywords: sol-gel ; immobilization ; entrapment ; bacteria ; atrazine ; biodegradation ; herbicide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Sol-gel entrapment was evaluated as a method for immobilization of an atrazine degrading Pseudomonas. It was found that the bacterium lost much of its atrazine degrading activity upon immobilization. However, partial activity could have been restored by amendment of nutrients. Bacteria immobilized using a prehydrolysis technique for the preparation of the sol-gel, retained better activity in comparison to bacteria immobilized using a composite calcium alginate/sol-gel procedure. Further study is underway to improve the activity of sol-gel entrapped bacteria.
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  • 24
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    Biodiversity and conservation 5 (1996), S. 1365-1378 
    ISSN: 1572-9710
    Keywords: Antarctic yeasts ; Antarctic microfungi ; terrestrial ecosystems ; biodegradation ; biodiversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Fungal biodiversity in Antarctic terrestrial ecosystems increases with the availability of water and energy, but cannot now be precisely described because of problems with identification and questions us to what organisms are truly indigenous. Yeasts probably predominate on continental Antarctica, while other microfungi usually do so in maritime and sub-Antarctica. Lists of nematophagous species and of microfungal species reported from maritime and sub-Antarctica are given. The ecological roles of these fungi are worthy of further research. The ability of common airspora and pathogens to survive and colonize should be investigated.
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  • 25
    ISSN: 1476-5535
    Keywords: alginate-encapsulated cells ; Pseudomonas ; soil ; survival ; biodegradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The survival and phenanthrene-mineralizing ability of free and alginate-encapsulatedPseudomonas sp UG14Lr cells were examined in a creosote-contaminated soil. Alginate encapsulation adversely affected both survival and phenanthrene mineralization. This was postulated to be due to concentration of water-soluble toxic compounds in the alginate beads. Toxicity studies showed that the concentrated water-soluble fraction of the creosote-contaminated soil may be toxic toPseudomonas sp UG14Lr in soil with a low moisture content. Survival of alginate-encapsulated cells improved with increasing soil moisture content. Free cells survived well at a steady population of 108 CFU g−1 dry soil for 28 days in the creosote-contaminated soil. However, phenanthrene mineralization was not improved compared to the uninoculated control. This was attributed to the existence of indigenous phenanthrene-mineralizing microorganisms already present in this contaminated soil. The effect of calcium hypochlorite and Germiphene on survival of and phenanthrene mineralization by free and alginate-encapsulatedPseudomonas sp UG14Lr cells in creosote-contaminated soil was also studied. Addition of 0.1% (w/w dry soil) calcium hypochlorite reduced the introduced free cells to below detection limits (10 CFU g−1 dry soil) within 14 days, while Germiphene had no effect on cell numbers. Phenanthrene mineralization by free cells was not adversely affected by treatment with calcium hypochlorite or Germiphene. Survival of alginate-encapsulated cells after treatment with disinfectants was as poor as that without disinfection. The results show that alginate encapsulation may not be a suitable formulation for introduction ofPseudomonas sp UG14Lr into creosote-contaminated soils.
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  • 26
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    Journal of industrial microbiology and biotechnology 16 (1996), S. 309-318 
    ISSN: 1476-5535
    Keywords: biofilter ; BTEX ; biodegradation ; vapours
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A mixed culture, enriched from Sphagnum peat moss, contaminated with gasoline vapours, degraded individual and mixed components of BTEX (benzene, toluene, ethylbenzene, xylene). Complete degradation of radiolabelled toluene by the mixed culture was observed in mineralisation studies. Individual isolates from a mixed culture containingPseudomonas maltophilia, P. testosteroni andP. putida biotype A exhibited contrasting BTEX degradation patterns. WhileP. putida biotype A degraded all of the BTEX compounds,P. maltophilia andP. testosteroni, appeared unable to degrade benzene and xylenes, respectively. When the peat, inoculated with the mixed culture, was used as a biofilter (6.2 cm diameter ×93 cm length) for degradation of toluene and ethylbenzene vapours, percentage removal efficiencies were 99 and 85, respectively. When the capacity of the biofilter to degrade a combination of BTEX compounds was evaluated, percentage removal efficiencies for toluene, ethylbenzene,p-xylene,o-xylene and benzene were 99, 85, 82, 80 and 78, respectively. The importance of using the mixed culture as an inoculum in the biofilter was established and also the relationship between contaminated vapour flow rate and percentage removal efficiency.
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  • 27
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    Journal of industrial microbiology and biotechnology 17 (1996), S. 463-469 
    ISSN: 1476-5535
    Keywords: bioplastics ; biodiversity ; biodegradation ; streptomycetes ; polyhydroxyalkanoates ; poly(ε-caprolactone) ; BIONOLLE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The biodiversity and occurrence in nature of bioplastic-degrading microorganisms are exemplified by the identification of 695 strains, isolated from different environments, such as soils, composts, natural waters, and sludge, that are able to degrade the bacterial polyester poly(3-hydroxybutyrate)in vitro. These microorganisms belong to at least 57 different taxa, including Gram-negative and Gram-positive bacteria, streptomycetes, and moulds. The literature on the biodiversity of poly(3-hydroxybutyrate)-degrading microorganisms is reviewed. The degrading abilities of 171 streptomycete strains were investigated on four different bacterial poly(3-hydroxyalkanoates), and the synthetic polyesters poly(ε-caprolactone) and BIONOLLE, and most of these strains degraded at least three different polymers.
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  • 28
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    World journal of microbiology and biotechnology 12 (1996), S. 207-212 
    ISSN: 1573-0972
    Keywords: Alkenylbenzenes ; biodegradation ; bioremediation ; microorganisms ; styrene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Alkenylbenzenes are produced in large quantities by the petrochemical industry. The simplest of these alkenylbenzenes, styrene, is in widespread use in the polymer-processing industry and is thus found in many industrial effluents. Airborne gaseous emissions of styrene are particular problems due to the potential toxicity and carcinogenicity of the compound. The catabolic pathways involved in the degradation of styrene have been well characterised. With an increased knowledge of the adaptative response which microorganisms exhibit when exposed to higher styrene concentrations, together with an understanding of the genetic regulation of the catabolic pathways which operate in these microbial strains, it is likely that these organisms could be exploited in areas such as biotransformations, biocatalysis and bioremediation.
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  • 29
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    World journal of microbiology and biotechnology 12 (1996), S. 653-654 
    ISSN: 1573-0972
    Keywords: Benzene ; biodegradation ; Rhodococcus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Benzene was metabolized by Rhodococcus sp. 33 through the intradiol cleavage (ortho-) pathway producing cis-benzene glycol, catechol and cis, cis-muconic acid as the intermediates. This is the first elucidation of the pathway by which benzene is degraded by a gram-positive organism. The enzyme assays have also suggested that Rhodococcus 33 does not have a fully functional tricarboxylic acid cycle but may have an operational glyoxylate bypass.
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  • 30
    ISSN: 1572-9699
    Keywords: biodegradation ; chlorinated compounds ; freons ; methane formation ; phthalic acid esters ; phenol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The potential for biological transformation of 23 xenobiotic compounds by microorganisms in municipal solid waste (MSW) samples from a laboratory scale landfill reactor was studied. In addition the influence of these xenobiotic compounds on methanogenesis was investigated. All R11, 1,1 dichloroethylene, 2,4,6 trichlorophenol, dimethyl phthalate, phenol, benzoate and phthalic acid added were completely transformed during the period of incubation (〉 100 days). Parts of the initially added perchloroethylene, trichloroethylene, R12, R114, diethyl phthalate, dibutyl phthalate and benzylbutyl phthalate were transformed. Methanogenesis from acetate was completely inhibited in the presence of 2,5 dichlorophenol, whereas 2,4,6 trichlorophenol and R11 showed an initial inhibition, whenafter methane formation recovered. No transformation or effect on the anaerobic microflora occurred for R13, R22, R114, 3 chlorobenzoate, 2,4,6 trichlorobenzoate, bis(2 ethyl)hexyl phthalate, diisodecyl phthalate and dinonyl phthalate. The results indicate a limited potential for degradation, of the compounds tested, by microorganisms developing in a methanogenic landfill environment as compared with other anaerobic habitats such as sewage digestor sludge and sediments.
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  • 31
    ISSN: 1572-9729
    Keywords: biodegradation ; bioemulsifier ; biosurfactant ; polyaromatic hydrocarbons ; soil 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 Fifty-seven bacterial strains were isolated from PAH-contaminated soils using PAH-amended minimal medium. The isolates were screened for their production of biosurfactants and bioemulsifiers when grown in liquid media containing selected PAHs. The results suggest that many, but not all, of the isolates are able to produce biosurfactants or bioemulsifiers under the experimental conditions. The majority of the strains isolated on phenanthrene, pyrene, and fluoranthene were better emulsifiers than surface tension reducers and the stability of the formed emulsions was in general high. The strains isolated on anthracene were in general better in lowering the surface tension than in forming emulsions. In all strains, reduction of surface tension and emulsion formation did not correlate. However, in the majority of strains the two factors were associated with the bacterial cell surfaces, rather than the culture supernatants. Nevertheless, supernatants from selected surfactant-producing anthracene isolates increased the aqueous solubility of anthracene. Although a significant potential for surfactant and emulsifier production in the microbiota of the PAH-contaminated soils was found in this study, the ability of individual strains to mineralize PAHs did not coincide with production of surface-active compounds.
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  • 32
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    Biodegradation 7 (1996), S. 501-506 
    ISSN: 1572-9729
    Keywords: biodegradation ; Bis(2-ethylhexyl) phthalate ; 2-ethylhexanol ; 2-ethylhexanoic acid ; methane formation ; mono(2-ethylhexyl) phthalate ; phthalic acid esters
    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 degradation of bis(2-ethylhexyl) phthalate (DEHP) and its intermediary hydrolysis products 2-ethylhexanol (2-EH) and mono(2-ethylhexyl) phthalate (MEHP) was investigated in a methanogenic phthalic acid ester-degrading enrichment culture at 37°C. 2-Ethylhexanoic acid (2-EHA), a plausible degradation product of 2-EH, was also studied. The culture readily degraded 2-EH via 2-EHA to methane which was formed in stoichiometric amounts assuming complete degradation of 2-EH to methane and carbon dioxide. MEHP was degraded to stoichiometric amounts of methane with phthalic acid as a transient intermediate. DEHP remained unaffected throughout the experimental period (330 days).
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  • 33
    ISSN: 1572-9729
    Keywords: biodegradation ; sewage ; soil ; Pseudomonas aeruginosa ; fat replacement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Olestra is a non-caloric fat substitute consisting of fatty acids esterified to sucrose. Previous work has shown that olestra is not metabolized in the gut and is excreted unmodified in human feces. To better understand the fate of olestra in engineered and natural environments, aerobic bacteria and fungi that degrade olestra were enriched from sewage sludges, soils and municipal solid waste compost not previously exposed to olestra. Various mixed and pure cultures were obtained from these sources which were able to utilize olestra as a sole carbon and energy source. The fastest growing enrichment was obtained from activated sludge and later yielded an olestra-degrading pure culture of Pseudomonas aeruginosa. This mixed culture extensively degraded both 14C-fatty acid labeled olestra and 14C-sucrose labeled olestra during 8 days of incubation. Longer-term incubation with pure cultures of P. aeruginosa demonstrated that 〉98% of 14C-sucrose labeled olestra and 〉72% of 14C-fatty acid labeled olestra was mineralized to CO2 after 69 days. These results indicate that olestra degraders are present in environments not previously exposed to olestra and that olestra can serve as a sole carbon and energy source. Furthermore, a common bacterial species was isolated from activated sludge and shown to have the ability to degrade olestra.
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  • 34
    ISSN: 1573-8221
    Keywords: biodegradation ; restitution ; orderliness ; connective tissue ; allografts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Results are presented from a study in which the structural arrangement of the intercellular matrix was examined in preserved connective tissue fragments (allografts) after their implantation into rabbits to repair posttraumatic space-occupying defects in the capsular-ligamentous complex of the knee joint. Stages of biodegradation and restitution undergone by the interstitial substance of connective tissues after the implantation of allografts are identified.
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  • 35
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    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 2701-2708 
    ISSN: 0887-6266
    Keywords: poly(lactic acid) ; biodegradation ; crystallinity ; orientation ; physical aging ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of physical aging, degree of crystallinity, and orientation of poly(lactic acid) (PLA) were studied using differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). The samples of PLA with 96% [L] and 4% [D] contents were prepared by injection molding. The physical aging of PLA strongly depended on time and temperature. The change of rate of physical aging was very fast initially and slowed down as time increased. The enzymatic degradation of PLA was carried out with proteinase K at 37°C at a pH value of 8.6 in a Tris/HCl buffer solution. The enzymatic degradation rate was found to decrease as a function of physical aging (i.e., excess enthalpy relaxation). The rate of enzymatic degradation of PLA decreased with the increase in crystallinity. A threshold was observed when the heat of fusion was less than 20 J/g. The weight loss of PLA with a low level of crystallinity had no apparent change during any period of testing time. The rates of enzymatic degradation of stretched and injection-molded specimens were comparable. © 1996 John Wiley & Sons, Inc.
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  • 36
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    Biotechnology and Bioengineering 52 (1996), S. 102-108 
    ISSN: 0006-3592
    Keywords: polyphosphazenes ; biodegradation ; drug delivery ; mitomycin C ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article describes the synthesis of biodegradable polyphosphazenes. The rate of degradation can be varied in a controllable manner by the introduction of hydrolysis-sensitive amino acid ester side groups or by blending of polymers. Biodegradable polyphosphazenes can be used for the preparation of drug-containing implants and this is illustrated for devices containing the cytostatic agent mitomycin C. This article reviews data about the degradation characteristics of poly[(amino acid ester)phosphazene] derivatives that have been discussed previously. Some new data about MMC-containing poly[(organo)phosphazene] devices are discussed as well. © 1996 John Wiley & Sons, Inc.
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  • 37
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    Biotechnology and Bioengineering 51 (1996), S. 1-14 
    ISSN: 0006-3592
    Keywords: biodegradation ; desorption ; mathematical model ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model to describe polynuclear aromatic hydrocarbon (PAH) desorption, transport, and biodegradation in saturated soil was constructed by describing kinetics at a microscopic level and incorporating this description into macroscale transport equations. This approach is novel in that the macroscale predictions are made independently from a knowledge of microscale kinetics and macroscopic fluid dynamics and no adjustable parameters are used to fit the macroscopic response. It was assumed that soil organic matter, the principal site of PAH sorption, was composed of a continuum of compartments with a gamma distribution of desorption rate coefficients. The mass transport of substrates and microorganisms in a mesopore was described by diffusion and that in a macropore by one-dimensional advection and dispersion. Naphthalene was considered as a test PAH compound for initial model simulations. Three mechanisms of naphthalene biodegradation were considered: growth-associated degradation as a carbon and energy source for microbial growth; degradation for maintenance energy; and growth-independent degradation. The Haldane modification of the Monod equation was used to describe microbial growth rates and to account for possible growth inhibition by naphthalene. Multisubstrate interactions were considered and described with a noninteractive model for specific growth rates. The sensitivity of selected model parameters was analyzed under conditions when naphthalene was the sole growth-rate-limiting substrate. The time necessary to achieve a specific degree of naphthalene biodegradation was found to be proportional to the initial concentration of naphthalene in soil organic matter. The biodegradation rate of naphthalene increased when the sorption equilibrium constant of naphthalene was reduced. The presence of an alternative carbon source inhibited naphthalene biodegradation in spite of the calculated increase in biomass. © 1996 John Wiley & Sons, Inc.
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  • 38
    ISSN: 0006-3592
    Keywords: biodegradation ; composting ; FTIR ; solid substrate fermentation and waste treatment ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The degradation of organic matter was evaluated by a quantitative Fourier transform infrared spectroscopy (FTIR) analysis technique. The degradation process was conducted in a bench-scale reactor under controlled operational conditions of 50°C, with 50-60% moisture content, and subjected to uniform aeration for 325 h. During the composting process, ATP concentration increased from 0.1 to 8 μg/g and the maximum CO2 evolution and O2 consumption rates reached 0.04 and 0.085 mmol/g-h, respectively. Polysaccharide content decreased approximately 50% while lignin content remained unchanged. Three regions of the FTIR spectra were used for quantification: 1070-974, 1705-1614, and 2995-2887 cm-1, which correspond to polysaccharides and aromatic and aliphatic compounds, respectively. The actual spectra quantification consisted of peak identification using a second derivative and curve fitting technique, followed by normalization using the internal standard CaCO3. The results obtained with the spectra quantification technique was then compared to commonly used wet chemistry extraction procedures. Reasonable correlation between the two techniques was obtained. © 1996 John Wiley & Sons, Inc.
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  • 39
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    Biotechnology and Bioengineering 50 (1996), S. 57-64 
    ISSN: 0006-3592
    Keywords: biofilter ; membrane ; biodegradation ; TCE ; anoxic ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article reports on the biodegradation of trichloroethylene (TCE) in a hollow-fiber membrane biofilter. Air contaminated with TCE was passed through microporous hollow fibers while an oxygen-free nutrient solution was recirculated through the shell side of the membrane module. The biomass was attached to the outside surface of the microporous hollow fibers by initially supplying toluene in the gas phase that flows through the fibers. While studies on TCE biodegradation were conducted, there was no toluene present in the gas phase. At 20-ppmv inlet concentration of TCE and 36-s gas-phase residence time, based on total internal volume of the hollow fibers, 30% removal efficiency of TCE was attained. At higher air flow rates or lower gas-phase residence times, lower removal efficiencies were observed. During TCE degradation, the pH of the liquid phase on the shell side of the membrane module decreased due to release of chloride ions. A mathematical model was developed to describe the synchronous aerobic/anaerobic biodegradation of TCE. © 1996 John Wiley & Sons, Inc.
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  • 40
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    Biotechnology and Bioengineering 51 (1996), S. 112-119 
    ISSN: 0006-3592
    Keywords: biodegradation ; self-cycling fermentation ; phenol ; Pseudomonas putida ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Self-cycling fermentation (SCF) in a stirred tank reactor was applied to the biodegradation of phenol by Pseudomonas putida. The technique resulted in stable and repeatable performance. Complete substrate consumption was achieved under all operating conditions investigated. SCF resulted in substrate utilization rates as high as 14.5 kg of phenol per cubic meter of fermentor volume per day of fermentation, higher than those that have been reported for batch, CSTR, and packed column fermentors. A mathematical model of the self-cycling fermentation process was expanded to include inhibitory substrate-microorganism combinations, and was shown to provide a good fit to both end-of-cycle and intracycle experimental data. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 41
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    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 65 (1996), S. 370-374 
    ISSN: 0268-2575
    Keywords: biodetoxification ; biodegradation ; chemical warfare agents ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Rhodococcus rhodochrous IGTS8 (ATCC 53968) was shown to be capable of utilizing 2-chloroethyl ethyl sulphide (CEES) as the sole source of sulphur for microbial growth. 2-Chloroethanol and a compound tentatively identified as 2-chloroethanesulfinic acid have been detected as metabolites. This demonstrates that carbon - sulphur bonds were cleaved in CEES prior to hydrolysis of the chlorine atom. These data indicate that Rhodococcus rhodochrous IGTS8 may be useful for the biodetoxification of the chemical warfare agent mustard (2,2′ dichlorodiethyl sulphide).
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  • 42
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    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 66 (1996), S. 300-304 
    ISSN: 0268-2575
    Keywords: waste gases ; flue gases ; BTEX ; VOC ; bioremediation ; biodegradation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three identical biofilters, run under the same conditions but inoculated with different mixed cultures, were fed a mixture of toluene, ethylbenzene, and o-xylene (TEX) gases. Inert porous perlite was used as support material, in contrast to the more conventional biofiltration systems where natural supports are used. Biodegradation started in all three biofilters a few hours after inoculation, without previous adaptation of the inocula to the toxic mixture. Despite acidification of the systems to pH values below 4·5, the elimination capacities reached were fully satisfactory. The best performing biofilter, in which bacteria were dominant, showed an elimination capacity of 70 g TEX m-3 h-1 with a near complete removal of the mixture up to an influent concentration of 1200 mg TEX m-3 at a gas residence time of 57 s. Most of the ingoing carbon was recovered as carbon dioxide in the outgoing gas. In the other biofilters fungi dominated and performance was slightly worse. With single substrates, the elimination capacity was higher for toluene and ethylbenzene than for the TEX mixture, whereas o-xylene removal was slowest in all cases. Also when feeding the mixture to the biofilters, o-xylene was removed most slowly.
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  • 43
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    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 66 (1996), S. 251-264 
    ISSN: 0268-2575
    Keywords: anaerobic digestion ; anhybrid reactors ; organic solvents ; biodegradation ; trace elements ; population composition ; granular structure ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The performance of anaerobic hybrid reactors treating an organic solvent-containing synthetic pharmaceutical wastewater was evaluated under various wastewater volumetric loading rates and influent compositional changes. The biodegradation, toxicity and treatability of the target C3 and C4 solvents, tert-butanol, isopropanol, isobutanol, sec-butanol and ethyl acetate, were examined. At a hydraulic retention time (HRT) of 2 days and volumetric loading rates ranging from 3·5 to 4·5 kg COD m-3 day-1, the reactors achieved total and soluble COD removal efficiencies of 97-99% in less than five times the HRT. These removal rates were achieved following the introduction of target solvents not previously supplied to the reactors. However, inadequate removal of tert-butanol resulted in a decrease in the soluble COD removal efficiency to 58%. Bacterial enrichments from the reactor biomass using tert-butanol as the sole substrate proved unsuccessful, confirming that tert-butanol is poorly degradable anaerobically. Inclusion of a trace metal cocktail in the feed did not affect steady-state reactor performance, but was beneficial during changes in the influent composition. After 405 days of operation, the matrix-associated biomass contributed only a minor fraction (2-4%) of the total biomass present in both reactors. On takedown, the retained biomass present in the matrix-free section of both reactors was found to be granular in nature, despite the omission of trace elements from the influent to one of the AHRs. The specific methanogenic activity profile of the granular sludge from the trace element limited AHR was, however, significantly lower (α = 0·05) than that of the reference AHR.
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