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  • 2010-2014
  • 1985-1989  (879)
  • 1985  (879)
  • Biochemistry and Biotechnology  (457)
  • Engineering General  (422)
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Years
  • 2010-2014
  • 1985-1989  (879)
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Effect of ultrasound treatment on the extraction of insulin (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1223-1228 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Insulin production requires a prolonged extraction process. An ultrasound method of insulin extraction was developed to increase efficiency. Application of ultrasound resulted in a significant increase in the extraction process as a result of pancreas tissue dispergation, destruction of the pancreas cells, intensive mixing, separation of particles, and increase in the interphase pancreas-extractive medium. Optimal technological parameters of insulin extraction were established: ultrasound frequency, 19.5 kHz, specific intensity of ultrasound, 3.3 W/cm2; time of ultrasound exposure, 5-10 min; and influence of cavitation process. Effectiveness of insulin extraction depends on the properties of the extractive medium. Optimal conditions were pH, 1.6-1.7, concentration of alcohol, 75%, temperature of extractive mixture, 13-17°C; ratio of ground pancreas to liquid extractive medium, 1 : 3.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270818
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  • 102
    Electronic Resource
    Electronic Resource
    Ethanol fermentation of raw cassava starch with Rhizopus koji in a gas circulation type fermentor (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1270-1273 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies have been conducted in a gas circulation type fermentor in order to characterize the ethanol fermentation of uncooked cassava starch with Rhizopus koji. Results showed that ethanol concentration reached 13-14% (v/v) in 4-day broth, and the maximum productivity of ethanol was 2.3 g ethanol/L broth h. This productivity was about 50% compared to the productivity of a glucose-yeast system. Ethanol yield reached 83.5-72.3% of the theoretical yield for the cassava starch used. The fermentor used in the present work has been proven by experiment to be suitable for ethanol fermentation of the broth with solid substrate.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270823
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  • 103
    Electronic Resource
    Electronic Resource
    Optimization of organic solvent in multiphase biocatalysis (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1258-1269 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The microbial epoxidation of propene and 1-butene was used to study some fundamental aspects of two-liquid-phase biocatalytic conversions. Introduction of a water-immiscible organic solvent phase in a free-cell suspension gave rise to a series of undesired phenomena, e.g., inactivation by the solvent, clotting of biomass, and aggregation of cells at the liquid-liquid interface. Immobilization of the cells in hydrophilic gels, e.g., calcium alginate, prevented direct cell-organic solvent contact and the related clotting and aggregation of biomass. However, the gel entrapment did not seem to provide additional protection against the organic solvent. The influence of various organic solvents on the retention of immobilized-cell activity was related to solvent properties like the polarity (as expressed by the Hildebrand solubility parameter) and the molecular size (as expressed by the molecular weight or molar volume). High activity retention was favored by a low polarity in combination with a high molecular weight. The solubility parameter also proved useful to describe the capacity of various organic solvents for oxygen and alkene oxides. This facilitated the optimization of the solvent polarity.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270822
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  • 104
    Electronic Resource
    Electronic Resource
    Masthead (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985) 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270901
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  • 105
    Electronic Resource
    Electronic Resource
    Regeneration of NAD(P)H by immobilized whole cells of Clostridium butyricum under hydrogen high pressure (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1277-1281 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized whole cells of Clostridium butyricum reduced both NAD+ and NADP+ in the presence of hydrogen at a pressure of 100 atm. The NAD+ and NADP+ reduction activities were 4.45 and 4.30 U/g dry cells, respectively [U = NAD(P)H regenerated, μ mol/min]. The amount of NADH regenerated by immobilized cells increased with increasing hydrogen pressure above 10 atm. Immobilized cells (6 mg dry cells) of Cl. butyricum completely converted NAD+ (6.4 μmole) to NADH for 5 h, whereas only 60% of NAD+ were reduced by free cells. Immobilized cells retained 89% activity after the 5-h reactions were repeated 4 times. L-Alanine was continuously produced at the rate of 12.8 μmol/min g dry cells from hydrogen, ammonium, and pyruvate with immobilized Cl. butyricum-alanine dehydrogenase.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270902
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  • 106
    Electronic Resource
    Electronic Resource
    Thermophilic anaerobic digestion of high strength wastewaters (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1374-1381 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Investigations on the thermophilic anaerobic treatment of high-strength wastewaters (14-65 kg COD/m3) are presented. Vinasse, the wastewater of alcohol distilleries, was used as an example of such wastewaters. Semicontinuously fed digestion experiments at high retention times revealed that the effluent quality of digestion at 55°C is comparable with that at 30°C at similar loading rates. The amount of methane formed per kilogram of vinasse drops almost linearly with increasing vinasse concentrations. This can be attributed to increasing concentrations of inhibitory compounds, resulting in increasing volatile fatty acid (VFA) concentrations in the effluent. The treatment of vinasse was also investigated using upflow anaerobic sludge blanket (UASB) reactors. Thermophilic granular sludge, cultivated on sucrose, was used as seed material. The sludge required a 4-month adaptation period, during which the size of the sludge granules decreased significantly. However, the settling characteristics remained satisfactory. After adaptation, high loading and methane generation rates could be accommodated at satisfactory treatment efficiencies, namely, 86.4 kg COD/m3 day and 26 m3 CH4(STP)/m3 day, respectively. As in the semicontinuously fed digesters, the effluent VFA concentrations were virtually independent of the loading rates applied, indicating that the toxicity of the vinasse is more important than the loading rate in determining the efficiency of the conversion of vinasse to methane.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270915
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  • 107
    Electronic Resource
    Electronic Resource
    Calculation of mean cell residence time for unsteady-state activated sludge systems (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1393-1393 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270920
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  • 108
    Electronic Resource
    Electronic Resource
    Studies on immobilized fungal spores for microbial transformation of steroids: 11 α-hydroxylation of progesterone with immobilized spores of Aspergillus ochraceus G8 on polyacrylamide gel and other matrices (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1392-1392 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270919
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  • 109
    Electronic Resource
    Electronic Resource
    Induction of Cellulases in chaetomium cellulolyticum by cellobiose (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1389-1391 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production of extracellular cellulases by Chaetomium cellulolyticum could be induced by slow feeding of cellobiose to the cultures. Both the rate of production and the amount of activity were comparable to that obtained in batch cultivation on cellulose. The specific filter paper activity of 2.06 U per mg protein was almost two times higher than that obtained in cellulose medium. Cellulases were not induced when glucose was slowly fed to the cultures. Changing the feed stream from glucose to cellobiose resulted in a rapid accumulation of cellulases. Thus cellobiose has a similar role in cellulase induction in C. cellulolyticum, as earlier shown for Trichoderma reesei.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270918
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  • 110
    Electronic Resource
    Electronic Resource
    Hydroxylation of biphenyl by Aspergillus parasiticus: Approaches to yield improvment in fermenter cultures (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1395-1402 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: We carried out experiments designed to increase the rate of production of 4,4′-dihydroxybiphenyl (biphenol) from biphenyl by Aspergillus parasiticus. We show that 0.5 mg/ml biphenyl, the substrate for the reaction, significantly inhibits growth of the organism and that at 0.04 mg/ml, 2-hydroxybiphenyl or 4-hydroxybiphenyl (an intermediate of the reaction) strongly inhibit oxygen uptake, probably by inhibition of mitochondrial electron transport. Both factors may contribute to the low hydroxylation rates observed previously [J. H. Golbeck and J. C. Cox, Biotechnol. Bioeng., 26, 434 (1984)]. We therefore adapted the organism to the presence of 0.08 mg/ml 2- and 4-hydroxybiphenyl in the growth medium and found that cultures of adapted strains hydroxylated biphenyl at rates ca. three-fold faster than control cultures. Once the fungal mycelia were grown, they could be recycled at least twice into fresh fermentation broth. Recycled organisms were capable of hydroxylating biphenyl more rapidly than cells in the primary fermentation culture and there was no lag period between introduction of biphenyl and the onset of hydroxylation. Cell recycle thus results in a considerable saving in carbon costs and fermentation time.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271002
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  • 111
    Electronic Resource
    Electronic Resource
    Effect of hydrogen peroxide pretreatment on the structural features and the enzymatic hydrolysis of rice straw (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1418-1426 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Assessment was made to evaluate the effect of hydrogen peroxide pretreatment on the change of the structural features and the enzymatic hydrolysis of rice straw. Changes in the lignin content, weight loss, accessibility for Cadoxen, water holding capacity, and crystallinity of straw were measured during pretreatment to express the modification of the lignocellulosic structure of straw. The rates and the extents of enzymatic hydrolysis, cellulase adsorption, and cellobiose accumulation in the initial stage of hydrolysis were determined to study the pretreatment effect on hydrolysis. Pretreatment at 60°C for 5 h in a solution with 1% (w/w) H2O2 and NaOH resulted in 60% delignification, 40% weight loss, a fivefold increase in the accessibility for Cadoxen, an one times increase in the water-holding capacity, and only a slight decrease in crystallinity as compared with that of the untreated straw. Improvement on the pretreatment effect could be made by increasing the initial alkalinity and the pretreatment temperature of hydrogen peroxide solution. A saturated improvement on the structural features was found when the weight ratio of hydrogen peroxide to straw was above 0.25 g H2O2/g straw in an alkaline H2O2 solution with 1% (w/w) NaOH at 32°C. The initial rates and extents of hydrolysis, cellulase adsorption, and cellobiose accumulation in hydrolysis were enhanced in accordance with the improved structural features of straw pretreated. A four times increase in the extent of the enzymatic hydrolysis of straw for 24 h was attributed to the alkaline hydrogen peroxide pretreatment.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271005
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  • 112
    Electronic Resource
    Electronic Resource
    Effect of pretreatments and fermentation on pore size in cellulosic materials (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1427-1433 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Surface area has been proposed as a major factor determining the extent of enzymatic hydrolysis of cellulose. We used cornstalk residue (CR) and Solka Floc BW-300 (SF) as substrates and NaOH (a cellulose swelling agent) and iron sodium tartrate (FeTNa, intercolates between cellulose microfibrils) as pretreatments to study the effect of surface area on extent of fermentation. Micropore sizes (8-130 Å) were determined by a solute exclusion technique using glucose, cellobiose, and polyethylene glycols as molecular probes. The pore size distributions follow the logistic model function: I = a/[1+exp(b - cX)] where I is pore volume; X = log D; D is the molecular probe diameter; and a, b, and c are constants. The pore volumes of CR (1.9 mL/g) and SF (1.6 mL/g) are increased to 2.1 mL/g by pretreatment with NaOH. Pretreatment of SF with NaOH and cornstalk residue with FeTNa caused an upward shift in the pore size distribution. Fermentation of untreated CR by rumen microbes resulted in a 46% loss of dry matter while increasing the internal pore size and decreasing the pore volume to 0.9 mL/g. Fermentation of NaOH pretreated CR resulted in a 73% loss of dry matter with little change in pore size, total pore volume, or fiber composition. Fiber analysis indicated that selective utilization of hemicellulose over cellulose in both fermentations was small. The data show that: (1) removal of hemicellulose and lignin increases dry matter disappearance upon fermentation of the remaining material; (2) relative to the size of bacterial cellulases (40-160 Å), the pretreatments have little effect on increasing accessibility of surface internal to the cellulose particles; and (3) the micropore changes caused by NaOH or FeTNa treatment do not explain the enchanced fermentation obtained for treated cornstalk residue. These observations infer that external or macropore surface properties may be a significant factor in determining the extent of utilization of the solid substrates by cellulolytic microorganisms.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271006
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  • 113
    Electronic Resource
    Electronic Resource
    Separation and purification of enzymes by continuous pH-parametric pumping (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1451-1457 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Trypsin and chymotrypsin were separated from porcine pancreas extract by continuous pH-parametric pumping. CHOM (chicken ovomucoid) was convalently bound to laboratory-prepared crab chitin with glutaraldehyde to form an affinity adsorbent of trypsin. The pH levels of top and bottom feeds were 8.0 and 2.5, respectively. Similar inhibitor, DKOM (duck ovomucoid), and pH levels 8.0 and 2.0 for top and bottom feeds, respectively, were used for separation and purification of chymotrypsin. ε-Amino caproyl-D-tryptophan methyl ester was coupled to chitosan to form an affinity adsorbent for stem bromelain. The pH levels were 8.7 and 3.0. Separation continued fairly well with high yield, e.g., 95% recovery of trypsin after continuous pumping of 10 cycles. Optimum operational conditions for concentration and purification of these enzymes were investigated. The results showed that the continuous pH-parametric pumping coupled with affinity chromatography is effective for concentration and purification of enzymes.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271009
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  • 114
    Electronic Resource
    Electronic Resource
    Semicontinuous affinity chromatography separations (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1477-1481 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The semicontinuous operation of affinity chromatography columns charged and eluted alternately is studied mathematically. A strongly nonlinear adsorption equilibrium relation is utilized to examine the periodic mode of adsorption and desorption. The governing differential equations are solved by the method of characteristics. The time interval between desorption and adsorption periods is estimated, and implications for separations are discussed to show the advantages of semicontinuous cyclic operation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271012
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  • 115
    Electronic Resource
    Electronic Resource
    Feasible and optimal retrofitting of batch-soluble to continuous-immobilized enzyme processes applied to adsorbed enzymes (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1458-1465 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The advantages of retrofitting an in situ soluble enzyme batch process to an immobilized enzyme continuous process are contrasted against the disadvantages by means of a dimensionless feasibility/optimization analysis. The general analysis is applied to the case of an adsorbed enzyme system where a maximum in activity occurs with respect to loading. For this case, a minimum in the ratio of enzyme-carrier complex working lifetime to in situ batch process time and a maximum in the cost difference between the in situ and retrofit processes occurs with respect to loading and retrofit process conversion. For the maximization of cost difference, the analysis also suggests a criterion that can be used to determine whether the values for optimal loading and retrofit conversion will result in the retrofit being economically feasible. When infeasibility occurs, qualitative sensitivity analysis for a variety of situations points out whether a catalyst or process modification will improve feasibility the most. Apart from forming the basis for an iterative retrofit process design algorithm, the modeling approach's ability to specify optimal values of catalyst properties such as loading lends itself to defining process-specific, catalyst design “targets” would be useful for those developing immobilized enzyme preparation methodology and those investigating enzyme-carrier interactions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271010
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  • 116
    Electronic Resource
    Electronic Resource
    Microbial Toxicity Monitor for in Situ Continuous applications (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1500-1506 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271016
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  • 117
    Electronic Resource
    Electronic Resource
    Characteristics of carbohydrate degradation and the rate-limiting step in anaerobic digestion (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1482-1489 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The characteristics of the degradation of cellulose, soluble starch, and glucose in the acidogenic phase and the effects of the substrate loading rate and biological solids retention time on the methanogenic phase of anaerobic digestion were investigated. The results obtained from continuous experiments using laboratory-scale anaerobic chemostat reactors elucidated the true rate-limiting step of anaerobic digestion. The specific rate of substrate utilization decreased in the following order: glucose, soluble starch, acetic acid, and cellulose. The rate of the hydrolysis of cellulose was so low that this was shown to be the rate-limiting step in overall anaerobic digestion. Among methanogenic bacteria Methanosarcina would provide a higher substrate utilization rate than Methanothrix, and the maximum allowable substrate loading rate in the methanogenic phase was 11.2 g acetic acid/L day.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260271013
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  • 118
    Electronic Resource
    Electronic Resource
    Equations and calculations of product yields and preferred pathways for butanediol and mixed-acid fermentations (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 50-66 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Using the available information of fermentation biochemistry, fermentation (stoichiometric) equations are derived for anaerobic saccharolytic fermentations of butanediol and mixed acids. The equations describe the interrelations among the fermentation products, biomass, and consumed substrate (glucose). The validity of the equations is tested using a variety of batch data from the literature. The validity of the equations is expected to extend to steady-state and transient fermentations, as well. Uses, improvements, and extensions of the equations are also discussed in detail. Among others, it is shown that the equations are useful for checking the consistency of experimental data, for calculating maximal yields and selectivities for the fermentation products, and calculating the extent of utilization of the Embden-Meyerhof-Parnas pathway versus the Hexose Monophosphate pathway of glucose utilization.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270108
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  • 119
    Electronic Resource
    Electronic Resource
    Isolation and partial characterization of a mutant of Penicillium funiculosum for the saccharification of straw (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 81-85 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Clearing of agar plates containing ball-milled, delignified straw has been used for screening mutants of Penicillium funiculosum IMI 87160 iii. The effects of glycerol and a number of sugars on the clearing were investigated for selecting derepressed mutants. The β-glucosidase synthesis by one such mutant, C22c, in shake flasks containing straw was not repressed by 5% glycerol, whereas activities on filter paper, CM-cellulose, and p-nitrophenyl-β-xylosidase were only partially derepressed; xylanase was extensively derepressed. The evidence for separate control of the enzymes involved in the solubilization of straw is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270110
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  • 120
    Electronic Resource
    Electronic Resource
    Dried calcium alginate/magnetite spheres: A new support for chromatographic separations and enzyme immobilization (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 137-145 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dried spheres made from an alginate solution containing magnetite particles have excellent potential as a support for enzyme immobilization and chromatographic applications. The beads were found to be much stronger than gels such as polyacrylamide and dextran, indicating that high flow rates and pressures could be used in column separations. The support withstood not only temperatures of up to 120°C, but also most pH values and common solvents. While some solutions, such as phosphate buffers, dissolved the spheres, stabilization with Tyzor TE® eliminated this problem. The physical properties of the beads include a glasslike density of 2.2 g/mL, excellent sphericity, low porosity, and a narrow size distribution. The magnetite present in the support allows the beads to be used for magnetic separations such as high gradient magnetic filtration. Their high degree of microroughness provides a large exposed surface area for enzyme and ligand binding. Mixed Actinomyces fradiae proteases and Aspergillus niger α-amylase, two enzymes representative of classes which attack large substrates, were immobilized on the bead's surface with high activity and stability. A cyanuric dye which can be used in chromatographic applications (Cibacron Blue F3GA®) was also readily coupled to the surface of this support with good yield. The support should have a wide range of applications in bioseparation and immobilized biochemical technology.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270206
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  • 121
    Electronic Resource
    Electronic Resource
    Effect of glucose supplements on the fermentation of xylose by Pachysolen tannophilus (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 171-176 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Hemicellulosic sugars, predominantly D-xylose, comprise about one-half the total carbohydrate that can be obtained from hardwoods and agricultural residues through dilute acid hydrolysis. Because rates and yields in the xylose fermentation are low, economic utilization of these materials as fermentation feedstocks is difficult. Pachysolen tannophilus formed 5.5% ethanol from 12% glucose but only 2% ethanol from 12% xylcose. Aeration doubled the specific rate of D-glucose fermentation by P. tannophilus, as compared to anaerobic fermentation, but the specific rate of the xylose fermentation remained unchanged. Periodic additions of 0.5% D-glucose to aerobic fermentations of 3% xylose increased the yield of ethanol from 0.28 g/g xylose to greater than 0.41 g/g xylose utilized. The rate of xylose utilization remained unchanged, and radiotracer studies showed that addition of 0.5% glucose did not inhibit xylose utilization under aerobic or anaerobic conditions. No enhancement was observed anaerobically, nor was enhancement observed with acid hydrolysates, apparently because of the presence of acetic acid which inhibited growth and fermentation.
    Additional Material: 5 Ill.
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  • 122
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    Masthead (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985) 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270301
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  • 123
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    Immobilization of Saccharomyces cerevisiae by adhesion: Treatment of the cells by Al ions (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 217-224 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The adsorption of aluminum ions by Saccharomyces cerevisiae has been investigated by determining adsorption isotherms and electrophoretic mobility. The adsorption of aluminum ensures a neutralization of the cell surface charge and allows adhesion of the cells to glass and polycarbonate. Glass slides have been taken as a negatively charged model support, allowing the authors to study in detail the process of adhesion. The cells are simply pretreated by an aluminum solution near pH 4. Bringing the Al-pretreated cells in contact with the support by sedimentation and washing the support and sediment makes it possible to obtain a single, dense, regular layer of cells adhering strongly to the support. Adhesion can also be obtained from a suspension flowing parallel to a vertical support, provided the flow velocity is sufficiently small; the amount of cells immobilized per unit support area is about one-half that obtained by sedimentation. The immobilized cells show a specific activity for ethanol production from glucose which is similar to cells in suspension.
    Additional Material: 10 Ill.
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  • 124
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    Nutrient-limited continuous culture in the phauxostat (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 187-191 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Stable steady-state growth of Escherichia coli B limited by succinate, phosphate, or sulfate ion over the range of specific growth rates of 0.025-0.51 h-1 was achieved using pH-controlled auxostasis in the phauxostat. The concentration of the growth-limiting substrate in the growth vessel could be varied at will in the region of the Monod half-maximal saturation constants by adjusting the concentration of that substrate in the reservior (at constant buffering capacity) or by varying the population density of the culture through changing the buffering capacity of the medium in the reservoir.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270214
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  • 125
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    Effect of pH on the batch fermentation of pullulan from sucrose mediumPresented at the 7th International Biotechnology Symposium, New Delhi, India, February 19-25, 1984. (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 202-207 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two strains of the yeast-like fungus Aureobasidium pullulans 2552 and 140B have been used for the fermentative production of the polysaccharide pullulan from a sucrose synthetic medium. In the batch fermentation, either in Erlenmeyers or in the fermentor, the pH of the culture medium was decreased rapidly from its initial pH value of 5.5 to the self-stabilized final value of 2.5 within 24 h. Experiments on the effect of initial pH on the fermentation revealed that at very low initial pH values, such as at pH 2, the polysaccharide production was in-significant. However, the biomass concentration obtained was very high at this very low initial pH value. This interesting phenomenon was served as the basic principle for the development of the bistaged pH fermentation process for the production of pullulan. In this process the first stage of fermentation was conducted at the very acidic pH for the best production of biomass. When the biomass concentration reached its maximum value, the second stage of fermentation was initiated by adjusting the medium pH to a higher value for promoting the synthesis of the polysaccharide. Experiments conducted in Erlenmeyers and in the fermentor confirmed this concept. The bistaged pH process enhanced the polysaccharide concentration in the medium, influenced the rheological properties of the fermentation broth, and has a potential of operation under nonsterile and nonaseptic conditions.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270216
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  • 126
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    Acid hydrolysis of sweet potato for ethanol production (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 316-320 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies were conducted to establish optimal conditions for the acid hydrolysis of sweet potato for maximal ethanol yield. The starch contents of two sweet potato cultivars (Georgia Red and TG-4), based on fresh weight, were 21.1 ± 0.6% and 27.5 ± 1.6%, respectively. The results of acid hydrolysis experiments showed the following: (1) both hydrolysis rate and hydroxymethylfurfural (HMF) concentration were a function of HCL concentration, temperature, and time; (2) the reducing sugars were rapidly formed with elevated concentrations of HCl and temperature, but also destroyed quickly; and (3) HMF concentration increased significantly with the concentration of HCl, temperature, and hydrolysis time.Maximum reducing sugar value of 84.2 DE and 0.056% HMF (based on wet weight) was achieved after heating 8% SPS for 15 min in 1N HCl at 110°C. Degraded 8% SPS (1N HCl, 97°C for 20 min or 110°C for 10 min) was utilized as substrate for ethanol fermentation and 3.8% ethanol (v/v) was produced from 1400 mL fermented wort. This is equal to 41.6 g ethanol (200 proof) from 400 g of fresh sweet potato tuber (Georgia Red) or an ethanol yield potential of 431 gal of 200-proof ethanol/acre (from 500 bushel tubers/acre).
    Additional Material: 5 Ill.
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  • 127
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    Preparative resolution of D,L-threonine catalyzed by immobilized phosphatase (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 247-252 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Hydrolysis of L- and D-O-phosphothreonines catalyzed by four different phosphatases, alkaline phosphatases from calf intestine and E. coli and acid phosphatases from wheat germ and potato, has been kinetically studied. Alkaline phosphatases were found to have comparable reactivities towards the optical isomers. On the other hand, both acid phosphatases displayed a marked stereoselectivity, hydrolyzing the L-ester much faster than its D counterpart. Wheat germ acid phosphatase was the most stereoselective enzyme: VL/VD = 24 and Km,L/Km,D = 0.17. This enzyme was immobilized (in k-carrageenan gel, followed by crosslinking with glutaraldehyde) and used for the preparative resolution of D,L-threonine: the latter was first chemically O-phosphorylated and then asymmetrically hydrolyzed by the immobilized phosphatase. As a result, gram quantities of L-threonine of high optical purity and O-phospho-D-threonine were prepared. Immobilized wheat germ phosphatase has been tested for the resolution of other racemic alcohols: serine, 2-amino-1-butanol, 1-amino-2-propanol, 2-octanol, and menthol. In all those cases, the enzyme was either not sufficiently stereoselective or too slow for preparative resolutions.
    Additional Material: 1 Ill.
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  • 128
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    Kinetics of ethanol inhibition in alcohol fermentation (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 280-285 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The inhibitory effect of ethanol on yeast growth and fermentation has been studied for the strain Saccharomyces cerevisiae ATCC No. 4126 under anaerobic batch conditions. The results obtained reveal that there is no striking difference between the response of growth and ethanol fermentation. Two kinetic models are also proposed to describe the kinetic pattern of ethanol inhibition on the specific rates of growth and ethanol fermentation: \documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{*{20}c} {\frac{{\mu _i }}{{\mu _0 }} = 1{\rm } - {\rm }\left( {\frac{P}{{P_m }}} \right)^\alpha } \hfill & {\left( {{\rm for}\ {\rm growth}} \right)} \hfill \\ {\frac{{\nu _i }}{{\nu _0 }} = 1{\rm } - {\rm }\left( {\frac{P}{{P'_m }}} \right)^\beta } \hfill & {\left( {{\rm for}\ {\rm ethanol}\ {\rm production}} \right)} \hfill \\ \end{array}$$\end{document} The maximum allowable ethanol concentration above which cells do not grow was predicted to be 112 g/L. The ethanol-producing capability of the cells was completely inhibited at 115 g/L ethanol. The proposed models appear to accurately represent the experimental data obtained in this study and the literature data.
    Additional Material: 5 Ill.
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  • 129
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    Induction of NADPH-linked D-xylose reductase and NAD-linked xylitol dehydrogenase activities in Pachysolen tannophilus by D-xylose, L-arabinose, or D-galactose (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 302-307 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Considerable interest in the D-xylose catabolic pathway of Pachysolen tannophilus has arisen from the discovery that this yeast is capable of fermenting D-xylose to ethanol. In this organism D-xylose appears to be catabolized through xylitol to D-xylulose. NADPH-linked D-xylose reductase is primarily responsible for the conversion of D-xylose to xylitol, while NAD-linked xylitol dehydrogenase is primarily responsible for the subsequent conversion of xylitol to D-xylulose. Both enzyme activities are readily detectable in cell-free extracts of P. tannophilus grown in medium containing D-xylose, L-arabinose, or D-galactose and appear to be inducible since extracts prepared from cells growth in media containing other carbon sources have only negligible activities, if any. Like D-xylose, L-arabinose and D-galactose were found to serve as substrates for NADPH-linked reactions in extracts of cells grown in medium containing D-xylose, L-arabinose, or D-galactose. These L-arabinose and D-galactose NADPH-linked activities also appear to be inducible, since only minor activity with L-arabinose and no activity with D-galactose is detected in extracts of cells grown in D-glucose medium. The NADPH-linked activities obtained with these three sugars may result from the actions of distinctly different enzymes or from a single aldose reductase acting on different substrates. High-performance liquid chromatography and gas-liquid chromatography of in vitro D-xylose, L-arabinose, and D-galactose NADPH-linked reactions confirmed xylitol, L-arabitol, and galactitol as the respective conversion products of these sugars. Unlike xylitol, however, neither L-arabitol nor galactitol would support comparable NAD-linked reaction(s) in cellfree extracts of induced P. tannophilus. Thus, the metabolic pathway of D-xylose diverges from those of L-arabinose or D-galactose following formation of the pentitol.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270314
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  • 130
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    Alkaline treatment of wheat straw for increasing anaerobic biodegradability (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 334-344 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Wheat straw was treated with NaOH and anaerobically digested for methane production. Alkaline treatment resulted in a greater than 100% increase in biodegradability of wheat straw. The potential of a process flow scheme employing high alkali concentration at ambient temperature with solids separation and recycle of filtrate containing residual alkali was explored. The effect of NaOH on the solubilization of cell wall constituents and potential problems of toxicity are discussed. A solubilization model was developed which is used to predict biodegradability of whole samples based on solids and filtrate biodegradabilities. Energy requirements and chemical costs are also addressed.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270319
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  • 131
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    Masthead (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985) 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270401
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  • 132
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    A standard formula for the determination of the initial rate of hydrolysis of carboxymethylcellulose (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 409-414 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The integrated rate equation of Huang, originally used to describe the hydrolysis of insoluble acid treated cellulose, is shown equally applicable in describing the hydrolysis of carboxymethylcellulose (CMC) using a dilution series of Cellulomonas sp. ATCC 21399 crude cellulase as enzyme preparation. Interpretation of the progress curves of hydrolysis of CMC according to the integrated rate equation is used to calculate a standard formula for the conversion of the rate of hydrolysis into the initial velocity of hydrolysis. The validity of the standard formula is tested, using enzyme preparations from Cellulomonas grown under varied conditions, and enzyme preparations containing purified endoglucanases from Cellulomonas.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270404
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  • 133
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    Suggestions for the operation of radial flow cells in cell adhesion and biofouling studies (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 434-438 
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    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An analysis of the radial flow cell is presented to show that the assumption of creeping laminar flow should be used cautiously. Simple models which account for the influence of fluid inertial forces over most of the width of the plate are reviewed. A modified Reynolds number is introduced which may be used to test the validity of the creeping flow solution.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270407
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  • 134
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    Preparation of optically active D-arylglycines for use as side chains for semisynthetic penicillins and cephalosporins using immobilized subtilisins in two-phase systems (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 420-433 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Optically active D-arylglycines, which are of interest for preparation of semisynthetic penicillins and cephalosporins, were isolated from the racemic mixtures of their derivatives using immobilized proteolytic enzyme subtilisin (EC No. 3.4.4. 16). The performance of these reactions in two-phase systems, consisting of water and an immiscible organic solvent, improved the yield, purity, and economics of the process by increasing the substrate solubility and reducing the rate of nonenzymatic hydrolysis. The proportion of the organic phase can be as much as 75% of the overall volume without seriously impairing the enzymatic activity. The optically pure D-and L-arylglycines were liberated from their D- and L-derivatives by acid hydrolysis. The substituent influence of the various arylglycine derivatives on the rate of the enzymatic cleavage reaction was investigated.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270406
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  • 135
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    Isomaltulose production using immobilized cells (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 471-481 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three strains of Erwinia rhapontici especially suitable for use in the form of nongrowing immobilized cells were selected by screening strains of cells for high activity and operational stability in an immobilized form. Immobilization in calcium alginate gel pellets was easily the best method of immobilizing E. rhapontici. Much greater operational stabilities were obtained than when other immobilization methods were used. Conditions of operation which optimize the activity, stability, and yield and the ease of operation of the immobilized cell columns working in a steady state are described. These include the effects of substrate concentration, diffusional restrictions and water activity, the concentration of cells immobilized, and the type of reactor used. Thus, the immobilized cells produce about 1500 times their own weight of isomaltulose during one half-life of use (ca. 1 year). Loss of activity was most closely correlated with the volume of substrate processed and so presumably is due to the presence of low concentrations of a cummulative inhibitor in the substrate. Methods for regenerating the activity of the immobilized cells by the periodic administration of nutrients, of forming isomaltulose by continuously supplying nutrients to growing immobilized cells, and of crystallizing isomaltulose from the column eluate are also described.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270412
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  • 136
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    Novel process for the production of cellulolytic enzymesSubject to a patent application. Presented at the 7th International Biotechnology Symposium, New Delhi, India, February 19-25, 1984. (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 456-462 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A novel process for the production of extracellular carboxymethylcellulase (CMCase) and xylanase by fermentation under nonaseptic or nonsterile conditions is described. The fermentation process is carried out under very acidic conditions of pH 2.0 by using a acidophilic cellulolytic fungus. Microbial contamination is avoided or minimized to an insignificant level under this acid pH condition. The culture medium for this production consists of a carbon source from cellulosics or lignocellulosics, such as Na-CMC, xylan, Avicel cellulose, cellulose powder, α-cellulose, sawdust, etc., or a mixture of the forementioned together with simple ingredients such as (NH4)2SO4, K2HPO4, MgSO4 and NaNO3. The fermentation is carried out at room temperature (28-30°C), under aerobic conditions, and without controlling the pH. The CMCase and xylanase produced are stable under very simple storage conditions, such as in the fresh culture medium not containing the substrate for a period of 3 days, at any temperature from 0 to 30°C. These extracellular enzymes have an optimum pH around 3, with the best range of pH from 2.0 to 3.6, for any temperature between 15 and 60°C. The optimum temperatures are 55°C for CMCase activity and 25-50°C for xylanase activity, at any pH between 2.0 and 5.2. The apparent Michaelis constants Km are 2.6 and 1.5 mg/mL for CMCase and xylanase of the culture filtrate, respectively.
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    URL: http://dx.doi.org/10.1002/bit.260270410
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  • 137
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    A Multispecies model of biological treatment with sequential pollutant oxidation (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 490-497 
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    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The multispecies biological treatment model including the consequent substrates consumption is suggested. The model describes the adaptation in the distribution of species that are included in the composition of activated sludge. It was shown that the effects of adaptation are similar for the consequent as well as simultaneous mechanisms of substrate oxidation.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270414
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  • 138
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    A microbial culture with oxygen-sensitive product distribution as a potential tool for characterizing bioreactor oxygen transport (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 482-489 
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    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The dissolved oxygen (DO) level has been shown to have a profound effect on the product distribution of a Bacillus subtilis culture, with acetoin being excreted with DO above 100 parts per billion (ppb) and butanediol below 100 ppb. The product concentration ratio changed rapidly in the 80-90 ppb range. Switching from one oxygen level to another caused one already accumulated product to be converted to the other in a reversible manner. Rates of change of 0.5-1 g/L h enabled detection within 10 min. Detection sensitivity is enhanced because the ratio of two concentrations can be measured. Remarkably sensitive to mixing rates, the culture responded to changes in stirring speed during experiments in which the dissolved oxygen was controlled at a constant level with a novel control system. Thus, the culture is capable of detecting dead zones in relatively well-mixed reactors and oxygen gradients in column and tubular reactors. High-viscosity effects can also be investigated since the culture grows well in xanthan gum solutions. Preliminary kinetic model development indicates that a useful model for simulating reactor mixing and transport effects can be developed to aid in the planning of experiments.
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    URL: http://dx.doi.org/10.1002/bit.260270413
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  • 139
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    Kinetics of condensation of glucose into maltose and isomaltose in hydrolysis of starch by glucoamylase (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 498-502 
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    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Kinetics of the condensation of glucose into maltose and isomaltose in the hydrolysis of starch by two types of glucoamylase (from Aspergillus niger and Rhizopus niveus) was studied both experimentally and theoretically. A kinetic model for the hydrolysis of starch by glucoamylase from A. niger was proposed. In this model the reversible hydrolysis of maltose and isomaltose and the kinetic parameters change were taken into consideration. Calculated values agreed approximately with the experimental results, and this simple kinetic model was found to have practical use. The rate of condensation of glucose into isomaltose by enzyme from A. niger was about three times larger than that by enzyme from R. niveus. At a higher initial concentration of starch a large amount of isomaltose was reversed, and the glucose yield was reduced significantly after very long reaction times.
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    URL: http://dx.doi.org/10.1002/bit.260270415
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  • 140
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    Ethanol productions from D-xylose and cellobiose by Kluyveromyces cellobiovorus (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 509-513 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Yeasts capable of fermenting both D-xylose and cellobiose to ethanol were screened. Of 213 species of yeasts surveyed, Kluyveromyces cellobiovorus sp. nov., a new species belonging to genus of Kluyveromyces, was selected as the sole strain. This strain accumulated 32, 22, and 19 g/L of ethanol from 8% glucose, D-xylose, and cellobiose, respectively. It was also shown that this strain produced ethanol from the enzymatic bagasse hydrolysate containing hexoses and pentoses more efficiently than Saccharomyces cerevisiae.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270417
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  • 141
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    Purification and characterization of endo-xylanases from Aspergillus niger. II. An enzyme of pl 4.5 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 533-538 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A homogeneous endo-xylanase (1,4-β-D-xylan xylanohydrolase, EC 3.2.1.8) was obtained from a crude Aspergillus niger pentosanase by chromatography with Ultrogel AcA 54, SP-Sephadex C-25 at pH 4.5, DEAE-Sephadex A-25 at pH 5.4, Sephadex G-50, and SP-Sephadex C-25 with a gradient from pH 2.8 to pH 4.6. It was much more active on soluble than on insoluble xylan, yielding large amounts of unreacted xylan and a mixture of oligosaccharides with chain lengths from two to six. No xylose or L-arabinose was produced. There was high activity on a xylopentaose through xylononaose mixture, but not on xylobiose, xylotriose, or xylotetraose. The enzyme had slight activity on untreated cellulose, carboxymethylcellulose, and pectin. Molecular weight was ca. 1.4 × 104, with an isoelectric point of 4.5 and an amino acid profile high in acidic but low in sulfur-containing residues. In a 25-min assay at pH 4.7, this endo-xylanase was most active at 45°C, with an activation energy from 5 to 35°C of 33.3 kJ/mol. The optimum pH for activity was 4.9. Decay in buffer was first order, with an activation energy at pH 4.7 from 48 to 53°C of 460 kJ/mol. Optimum pH for stability was about 5.6, where the half-life at 48°C in buffer was ca. 40 h.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270421
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  • 142
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    Purification and characterization of endo-xylanases from Aspergillus niger. III. An enzyme of pl 3.65 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 539-546 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An endo-xylanase (1,4-β-D-xylan xylanohydrolase, EC 3.2.1.8) from Aspergillus niger was purified to homogeneity by chromatography with Ultrogel AcA 54, SP-Sephadex C-25 at pH 4.5, DEAE-Sephadex A-25 at pH 5.4, Sephadex G-50, and DEAE-Sephadex A-25 at pH 5.15. The enzyme was active on soluble xylan, on insoluble xylan only after arabinosyl-initiated branch points were removed, and on xylooligosaccharides longer than xylotetraose. There was slight activity on carboxymethyl-cellulose, arabinogalactan, glucomannan, and p-nitrophenyl-β-D-glucopyranoside. The main products of the hydrolysis of soluble and insoluble xylan were oligosaccharides of intermediate length, especially the tri- and pentasaccharides. The isoelectric point of the enzyme was 3.65. It had a molecular weight of 2.8 × 104 by SDS-gel electrophoresis, and was high in acidic amino acids but low in those containing sulfur. Highest activity in a 20-min assay at pH 5 was between 40 and 45°C, with an activation energy up to 40°C of 11.1 kJ/mol. The optimum pH for activity was at 5.0. The enzyme was strongly activated by Ca2+.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270422
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  • 143
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    Masthead (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985) 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270501
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  • 144
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    Optimizing alcohol production from whey using computer technology (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 547-554 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study was undertaken with the major goal of optimizing the ethanol production from whey using computer technology. To reach this goal, a mathematical model that would describe the fermentation and that could be used for the optimization was developed. Kluyveromyces fragilis was the microorganism used to ferment the lactose in the whey into ethanol. Preliminary studies showed that K. fragilis produced about 90% of the theoretical ethanol yield when grown in whey-complemented media. However, when this yeast is grown in nonsupplemented whey media, it does not produce more than 32% of that yield. Comparative batch fermentations of lactose and whey-complemented media showed that whey possibly contains enhancing components for yeast growth and ethanol production. To obtain the mathematical model, the one-to-one effect of the process variables (lactose and yeast extract concentrations, air flowrate, pH, and dilution rate) on the ethanol production were first investigated. Experiments on the pH effect showed that a decrease in pH from 7 to 4 produced an increase in ethanol concentration from 16.5 to 26.5 g/L (50 g/L initial lactose). The results obtained from modeling of the continuous fermentation using the previously listed variables showed that air flowrate, pH, and dilution rate were the process variables that most influence the production of ethanol.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270423
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  • 145
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    The effect of growth temperature on the bioenergetics of photosynthetic algal cultures (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 555-561 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two photosynthetic algal cultures, one Chlorella vulgaris, and the other a Chlorogonium sp., were cultured under light limitations in chemostats. The effects of growth temperature on their energy yield and maintenance energy requirement were studied. It was observed that a lowering in temperature resulted in a lower maximum growth yield from the light energy, YG. This was attributed to two reasons. First, at low temperatures there was a change in the algal cell composition with more energy being expended to synthesize a higher biomass protein content. Secondly, at low temperatures, a cyanide-resistant respiratory pathway became operative which led to a decrease in the number of ATP being generated. The maintenance energy coefficient was a function of temperature increasing with decreasing temperature. This might reflect energy wastage by the cell at low temperatures. The maximum specific growth rate dropped with decreasing temperature, and can be described by an Arrhenius type rate-temperature model up to the optimal temperature for growth; i.e., activation energy remained constant.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270502
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  • 146
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    Purification and characterization of endo-xylanases from Aspergillus niger. I. Two isozymes active on xylan backbones near branch points (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 525-532 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two endo-xylanases (1,4-β-D-xylan xylanohydrolase, EC 3.2.1.8) were purified to homogeneity from a crude Aspergillus niger pentosanase preparation by Ultrogel AcA 54 gel permeation chromatography, SP-Sephadex C-25 cation exchange chromatography at pH 4.5, Sephadex G-50 gel permeation chromatography, and a second SP-Sephadex C-25 step, this one at pH 5.8. The two xylanases hydrolyzed soluble xylan more rapidly than insoluble branched xylan, but attacked each substance to an equal extent. Their low activity on a linear xylooligosaccharide mixture and absence of activity on insoluble xylan freed of branches suggest that the xylanases require a branch point nearby for significant attack. No xylose or L-arabinose was produced, the major products of low molecular weight being tri- and pentasaccharides and smaller amounts of di-, tetra-, and hexasaccharides. There was low activity on untreated and crystalline cellulose and on carboxymethylcellulose and no activity on other polysaccharides tested. These two xylanases had molecular weights of ca. 1.3 × 104 and similar amino acid profiles, high in acidic and low in sulfur-containing residues. Isoelectric points were 8.6 for I and 9.0 for II. Optimum pH values for activity were 6.0 and 5.5, respectively. In a 20-min assay at pH 5.5, each was most active at 45°C, with activation energies up to 40°C of 30.4 and 38.8 kJ/ mol, respectively. Optimum pH levels for stability were 5.0 and 6.0, with half-lives at 60°C and those pHs of 20 and 75 min, respectively.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270420
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  • 147
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    Low-cost digital counting interface for fermentation gas measurementReference to a company and/or product named by the U.S. Department of Agriculture is only for purposes of information and does not imply approval or recommendation of the product to the exclusion of others. (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 569-571 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270504
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  • 148
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    A mechanistic analysis of the inoculum requirement for the cultivation of mammalian cells on microcarriers (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 585-595 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For the cultivation of mammalian cells on microcarriers a minimum inoculum concentration is required to initiate cell attachment and subsequent cell growth. A critical cell number model has been proposed to elucidate the mechanism of the inoculum requirement. In this model it was hypothesized that after inoculation a critical number of cells per microcarrier is required for normal growth to occur; failure to acquire enough cells will impede cell growth. This critical cell number model was expressed mathematically and used to simulate cell distribution and growth on microcarriers under different cultivation conditions. By comparing the simulated growth kinetics with the experimental results, the actual critical cell number per microcarrier was identified. The critical number could be reduced by employing an improved medium for the cultivation.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270507
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  • 149
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    Malic acid production by an electrochemical reduction system combined with the use of diaphorase and methylviologen (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 596-602 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A regenerating reaction combined with the use of native malate dehydrogenase, native diaphorase, methylviologen, NAD, oxalacetic acid as the substrate and lipoamide as a stabilizer was carried out in the presence of electrolysis. Consequently, malic acid was efficiently produced from oxalacetic acid in the regenerating reaction. A glassy carbon bead electrode was used as a cathode. Twenty four milliamperes were passed at a rotation speed of 500 rpm, 29.8 ± 0.3°C and -1.0 V. It was found that lipoamide has a stabilizing effect on malate dehydrogenase and diaphorase. Low concentration (50 μM) of NAD was also effective for the stabilization of malate dehydrogenase. NADH regeneration activity based on malic acid production rate was 4.7 U/mg of the enzyme protein of the commercial diaphorase preparation. The current efficiency was more than 74%, compared with the theoretical yield, in the presence of enough oxalacetic acid.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270508
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  • 150
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    Filament formation and ethanol production by Zymomonas mobilis in adsorbed cell bioreactors (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 626-631 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Zymomonas mobilis immobilized on microporous ion exchange resins has previously been shown to allow the attainment of high ethanol productivities in packed-bed bioreactors. The formation of bacterial filaments after several days of continuous operation, however, had resulted in excessive pressure increases across the reactor bed. The present work examines techniques for controlling filament formation by Z. mobilis in two reactor sizes (161 mL and 7.85 L) and a feed glucose concentration of 100 g/L. By controlling the fermentation temperature at 20-25°C it has been possible to eliminate filament formation by Z. mobilis and to operate the larger bioreactor for 232 h with an ethanol productivity of 50 g/L h (based on total reactor volume). The rate of ethanol production has been shown to be very sensitive to temperature in the range 20-30°C, and it is likely that slightly higher temperatures than those used in this study will improve ethanol productivity while still permitting long-term operation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270512
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  • 151
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    Calculation of mean cell residence time for unsteady-state activated sludge systems (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 695-703 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A formulation to calculate the mean cell residence time (MCRT or sludge age) of unsteady-state activated sludge systems is presented. The formulation was studied by applying it to data generated by computer simulation and to data obtained from an actual wastewater treatment plant. The computer simulation study allowed the effects of step and pulse changes in biochemical oxygen demand (BOD) loading, and step changes in a control variable, waste sludge flow rate, to be studied independently of each other and of other disturbances. The unsteady-state MCRT formulation (herein called the dynamic sludge age, or DSA) was found to be an improvement over the traditional steady-state calculation, both for process control, and for research into activated sludge dynamics.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270519
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  • 152
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    Structured modeling of the anaerobic digestion of biomass particulates (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 638-649 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anaerobic digestion of biological organic particulates to methane has been described by a structured mathematical model based on multiple-reaction stoichiometry, conventional material balances, and liquid phase equilibrium chemistry. A general stoichiometric treatment for any set of multiple biological reactions is derived based on a unit mass of oxggen equivalents of the reactions limiting substrate. The model agrees well with two existing experimental studies of anaerobic digestion of biomass particulates. Hypothetical computer simulations are presented to illustrate possible instabilities of the anaerobic process under various operating scenarios.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270514
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  • 153
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    Electronic Resource
    Carboxypeptidase a immobilization on activated styrene-maleic anhydride systems (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 675-680 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The copolymer styrene-maleic anhydride (SMA) was activated to various forms to create enzyme coupling groups. Carboxypeptidase A (CPA) was Immobilized on these supports to enhance their thermal and chemical stability. Immobilized enzyme retained 60-70% of the original activity. When kept at 60°C, while free enzyme was deactivated within 30 min, the immobilized enzyme retained 40% of initial activity at the end of 3 h. The half-life of free enzyme was only 21 min, while for immobilized enzyme it was enhanced up to 3 h. Also, the immobilized enzyme could be repeatedly used over 50 times retaining almost 50% of original activity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270517
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  • 154
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    Enzymic saccharification of pretreated wheat straw (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 650-659 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies of pretreatment of wheat and its subsequent saccharification by Trichoderma reesei cellulases are reported. Steam explosion was found to be the most effective of the pretreatment methods tested. Data are presented describing the effect of enzyme and substrate concentration on the rate and degree of hydrolysis. Significant inhibition of the cellulases was observed when sugar concentrations were 6% or higher. This inhibition increased when glucose and ethanol were present simultaneously. Adsorption of enzymes to the substrate was followed during a 24-h hydrolysis period. An initial rapid and extensive adsorption occurred, followed by a short desorption period that was followed in turn by a further increased adsorption peaking after 3 h. Intermediate removal of hydrolysate, particularly in combination with a second addition of enzyme, clearly improved the yield of saccharification compared to an uninterrupted hydrolysis over a 24-h period. Thus, a 74% yield of reducing sugars was obtained. Furthermore, an increase in the amount of recoverable enzymes was observed under these conditions. Evidence is presented that suggests that a countercurrent technique, whereby free enzymes in recovered hydrolysate are adsorbed onto new substrate, may provide a means of recirculating dissolved enzymes.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270515
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  • 155
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    The effect of pH on nitrogen supply, cell lysis, and solvent production in fermentations of Clostridium acetobutylicum (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 681-694 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In batch fermentations of C. acetobutylicum, with 5 g/L yeast extract and 50mM glucose, the ratio of ammonium to glucose affected solvent production when the pH was left to vary uncontrolled from 4.5 to 3.65. High solvent production was observed for a low ratio. When the pH was controlled at 4.5, only acids were produced for all ratio values. At a low ammonium-to-glucose ratio, solvents were produced when the pH was controlled at 3.7. Acids only were produced for a low ratio value at pH 4.0 or for a high ratio value at pH 3.7. In continuous cultures, mostly acids were produced under glucose limitation, but solvents were produced under nitrogen limitation. It was concluded that the nitrogen availability controls solvent production and that the pH affects the availability of organic nitrogen. Biomass autolysis at the stationary phase of batch cultures was reversibly inhibited at pH values less than 3.8. In batch fermentations, the overall molar growth yields on ATP (YATP) varied from 5.5 to 9.0 and the transient yields from 5.5 to 15.5. In continuous cultures, the YATP values varied from 5.5 to 14.7 under glucose limitation, and from 6.1 to 9.3 under nitrogen limitation. The YATP depended on the ammonium to glucose ratio and the culture pH, but did not show the usual dependence on the specific growth rate in batch cultures. The experiments seem to confirm the hypothesis that solvent production is controlled by the demand and availability of ATP.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270518
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  • 156
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    Effects of temperature and dilution rate on the copy number of recombinant plasmid in continuous culture of Bacillus stearothermophilus (pLP11) (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 721-728 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The penicillinase yield YP/X (U/g cell) of a transformant Bacillus stearothermophilus CU21 (pLP11) in continuous culture of LGP broth at 44, 47.5, and 50°C, respectively, depended not only on temperature, θ (°C), but also on dilution rate, D (h-1), in a peculiar fashion that could not have been realized if the product were from the gene on the chromosome rather than the plasmid. The gene dosage effect could account for the unusual dependence of YP/X on θ and D, because the mode of YP/X as a function of D at a given temperature resembled that of plasmid content Cp (mg plasmid/g cell) vs. D at the same temperature. In other words, Cp, corresponding to the copy number of plasmid per grams of cell, could be controlled by either θ, D, or both in this instance. However, when the gene expression efficiency, ε (U/ng plasmid), was plotted versus Cp, the effects of θ and D on the expression became indistinct.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270522
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  • 157
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    Purification of glucagon by subunit exchange chromatography (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 704-710 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Glucagon was immobilized onto Sepharose matrices activated with CNBr or tresyl chloride, as a function of several parameters including pH of coupling, concentration of added polypeptide, and presence or absence of urea. The hormone was linked to the matrix through a single point per molecule, namely, the ε -amino group of Lys12 when the coupling was carried out at alkaline pH, or the imidazole group of His1 when the coupling was carried out at acidic pH. Glucagon immobilized at alkaline pH interacted specifically with soluble glucogon. The extent of self-association was similar to that of free glucagon, which exists in solution in a monomer-trimer equilibrium whose association constant is highly dependent on the characteristics of the buffer (pH, ionic strength, and nature of anions). The immobilized hormone proved to be suitable for the purification of the free one from a pancreatic extract. After a preliminary treatment with charcoal-dextran, the extract was percolated on a glucagon-Sepharose column under associating conditions (high concentrations of salting out anions and alkaline pH) and then, following a washing to remove extraneous compounds, the specifically bound hormone was eluted under dissociating conditions (low ionic strength). The subunit exchange chromatography of the extract gave a ca. 90% pure product. The overall recovery of the process was ca. 66%. The leakage of immobilized hormone was 40% in the case of CNBr activation of Sepharose and 15% in the case of tresyl chloride activation, after an eight-day treatment under working conditions.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270520
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  • 158
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    Performance of an upflow anaerobic reactor combining a sludge blanket and a filter treating sugar waste (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 800-806 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new hybrid reactor, the upflow blanket filter (UBF), which combined on open volume in the bottom two-thirds of the reactor for a sludge blanket and submerged plastic rings (Flexiring, Koch Inc., 235 m2/m3) in the upper one-third of the reactor volume, was studied. This UBF reactor was operated at 27°C at loading rates varying from 5 to 51 g chemical oxygen demand (COD)/L d with soluble sugar wastewater (2500 mg COD/L). Maximum removal rates of 34 g COD/L d and CH4 production rates of 7 vol/vol d [standard temperature and pressure (STP)] were obtained. The biomass activity was about 1.2 g COD/g volatile suspended solids per day. Conversion (based on effluent soluble COD) was over 93% with loading rates up to 26 g COD/L d. At higher loading rates conversion decreased rapidly. The packing was very efficient in retaining biomass.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270608
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  • 159
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    β-Glucosidase of Penicillium funiculosum. I. PurificationThis report is National Chemical Laboratory Communication No. 3548 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 781-785 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A strain of Penicillium funiculosum, isolated in this laboratory, produced in high yield both endo- and exo-glucanases and β-glucosidases, which were suitable for the saccharification of cellulosic materials. The isolation of the β-glucosidase of this organism, which differs from other β-glucosidases of fungi in its substrate specificity, by preparative electrophoresis, is described in this article. The organism was grown on a lactose-casein medium and the culture filtrate concentrated by ammonium sulfate precipitation and dialysis. Electrophoresis was carried out on large slabs of polyacrylamide gel in an anodicrun in the presence of borate at pH 7. After elution of active fractions, a cathodic run was made at pH 6.0. Two precipitations with ammonium sulfate resulted in a homogeneous enzyme (specific activity 174 IU/mg). A second isozyme was also produced by P. funiculosum on cellulose-wheat bran medium. This isozyme was purified by electrophoresis at pH 7.0 in the absence of borate and was obtained free from other isozymes of β-glucosidase and cellulases.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270605
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  • 160
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    β-Glucosidase of Penicillium funiculosum. II. Properties and mycelial bindingThis report is National Chemical Laboratory Communication No. 3549 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 786-791 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The properties of two isozymes of β-glucosidase of Penicillium funiculosum (part I of this series) are described. The molecular weights of isozyme 1 was 2.3 × 105 by gel filtration and 1.2 × 105 by SDS gel electrophoresis, indicating two subunits. The molecular weight of isozyme 2 was unusually low for a fungal β-glucosidase: 1.6 × 104 by gel filtration and 3.7 × 104 in the presence of isopropanol. The two enzymes differed from other fungal β-glucosidases in their substrate specificities. They showed high activity with pNPG, cellobiose, cellotriose, cellotetraose, cellopentaose, gentiobiose, and laminarin, but were inactive with filter paper, CM cellulose, or derivatives or stabilized by bovine serum albumin and several alcohols such as butanol and propanol. It was inhibited by glucono-δ-lactone (Ki = 0.67μM) and glucose (Ki = 0.92mM).The enzyme was quantitatively adsorbed by P. funiculosum mycelium at pH 4 and the immobilized enzyme was as enzymically active as the free enzyme, but more heat stable. The binding efficiency was very high (5000 IU enzyme/g mycelium). It could be quantitatively eluted with buffers at pH 7 or by 0.02M Ca, Mg, or Al chlorides. The binding was selective, since mycelium grown on lactose could produce and also bind only β-glucosidase isozyme 1, whereas mycelium grown on cellulose could produce as well as bind both β-glucosidase isozymes as well as cellulases. Mycelial binding was unaffected by washing with EDTA or trypsinization, but was totally lost by washing with dilute KOH, HCl, or ethylenediamine.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/bit.260270606
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  • 161
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    Control of ammonium concentration in Escherichia coli fermentations (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 818-824 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A control system has been devised for the maintenance of stable ammonium concentrations throughout a fedbatch fermentation. The control system is based on an ammonia gas-sensing electrode that monitors a pH-adjusted effluent stream from the fermentor. To overcome the time lag between the fermentor and the electrode, feedback control included metered flows of ammonium to both the fermentor and the electrode vessel. The system was used to study the growth of Escherichia coli B (ATCC 11303) at controlled ammonium concentrations of 5 to 200mM. Apparent specific growth rates, biomass and protein production, and glucose yields were essentially constant from 5 to 170mM. Above 170mM ammonium growth was inhibited. As ammonium concentration decreased from 170 to 5mM, ammonium yields increased from 1 to 24 g cell dry wt/g ammonium utilized. The results demonstrate that control of ammonium concentrations at levels so low that ammonium would be exhausted in batch fermentations can significantly increase overall ammonium yields.
    Additional Material: 7 Ill.
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  • 162
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    The use of a hydrophobic resin as a product reservoir in steroid transformations (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 825-831 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Particles of the hydrophobic resin polydimethylsiloxane were found to preferentially accumulate steriods on the basis of their hydrophobicity. Thus, the resin selectively sorped the steroid products resulting from the transformation of diosgenin by Nocardia rhodochrous, with the result that higher yields of the later biotransformation product, 1-dehydrodiosgenone, and lower yields of the first product, diosgenone, were obtained than in the absence of resin. Furthermore, steroids accumulated by the resin were available for further biotransformation, so that a two-step reaction forming androstenes from a crude extract of furostanol glycosides (obtained from fenugreek seed) could be carried out. The first step involves deglycosylation and is catalyzed by Fusarium solani. In the presence of resin the water-insoluble diosgenin product becomes sorped to the resin and can be easily transferred to a second fermentation in which diosgenone, 1-dehydrodiosgenone, and androstenes were formed by Mycobacterium phlei. These compounds were completely accumulated by the resin at the end of the fermentation. This procedure is logistically more convenient than the conventional chemical process and illustrates the potential of biotechnological processes in which simultaneous reaction, product isolation, and product purification occur.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270611
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  • 163
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    Application of L-(+)-Lactate electrode for clinical analysis and monitoring of tissue culture medium (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 837-841 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: L-(+)-Lactate oxidase (EC 1.1.3.2) was immobilized onto the porous side of a cellulose acetate membrane with asymmetric structure which has selective permeability to hydrogen peroxide. The lactate electrode was constructed by combination of a hydrogen peroxide electrode with the immobilized enzyme membrane. Properties of the enzyme membrane and characteristics of the lactate electrode were clarified for the determination of L-(+)-lactic acid. The lactate electrode responded linearly to L-(+)-lactic acid over the final concentration 0-0.25 mmol/L within 30 s. When the enzyme electrode was applied to the determination of L-(+)-lactic acid in control serum, within-day precision (CV), analytical recovery, and correlation coefficient between the electrode method and the colorimetric method were 1.4% with a mean value of 4.54 mmol/L, 98.0%, and 0.986, respectively. The lactate electrode was sufficiently stable to perform 1040 assays over 13 days operation for the determination of L-(+)-lactic acid. The dried immobilized enzyme membrane retained 84% of its initial activity after storage at 4°C for 12 months. Moreover, the enzyme electrode was applied to the monitoring of culture medium for human melanoma cells. L-(+)-Lactate production and D-glucose consumption were closely related to cell numbers.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270613
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  • 164
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    Kinetics of the hydrolysis of lean meat protein by alcalase: Derivation of two alternative rate equations and their fit to experimental data (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 861-869 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two rate equations have been developed to model the hydrolysis of ground lean meat protein by Alcalase. The first equation was based on classical Michaelis-Menten kinetics and the second on the adsorption of enzyme to the protein prior to reaction. It was assumed that this adsorption could be modelled by a Langmuir-type adsorption isotherm. Each equation considered the enzyme to be competitively inhibited by reaction product, and considered enzyme inactivation to be first order. Both rate equations have been fitted to experimental data obtained from the hydrolysis of meat protein by Alcalase. Initial rate data indicated that the adsorption model was more appropriate. However, both equations gave satisfactory fits to 11 reaction progress curves determined over a wide range of enzyme and substrate concentrations.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270616
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  • 165
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    Determination of km and De from a one-shot experiment of enzyme immobilization (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 883-886 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270619
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  • 166
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    Reaction kinetics of cephalexin synthesizing enzyme from Xanthomonas citri (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 953-960 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In enzymatic synthesis of cephalexin from D-α-phenylglycine methyl ester (PGM) and 7-amino-3-deacetoxy-cephalosporanic acid (7-ADCA) using α-acylamino-β-lactam acylhydrolase from Xanthomonas citri, it was found that this enzyme catalyzes all three reactions including PGM hydrolysis, cephalexin synthesis, and cephalexin hydrolysis. Based on our experimental results, a mechanistic kinetic model for cephalexin synthesizing enzyme system having acyl-enzyme intermediate was proposed. From this kinetic model, the reaction rate equations for three reactions were derived, and the kinetic parameters were evaluated. A good agreement between the simulation results and the experimental results was found.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270705
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  • 167
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    An immobilized cell reactor with simultaneous product separation. I. Reactor design and analysis (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 932-942 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A four-phase reactor-separator (gas, liquid, solid, and immobilized catalyst) is proposed for fermentations characterized by a volatile product and nonvolatile substrate.In this reactor, the biological catalyst is immobilized onto a solid column packing and contacted by the liquid containing the substrate.A gas phase is also moved through the column to strip the volatile product into the gas phase. The Immobilized Cell Reactor-Separator (ICRS) consists of two basic gas-liquid flow sections: a cocurrent “enricher” followed by a countercurrent-“stripper”.In this article, an equilibrium stage model of the reactor is developed to determine the feasibility and important operational variables of such a reactor-separator. The ICRS concept is applied to the ethanol from whey lactose fermentation using some preliminary immobilized cell reactor performance data. A mathematical model for a steady-state population based on an adsorbed monolayer of cells is also developed for the reactor. The ICRS model demonstrated that the ICRS should give a significant increase in reactor productivity as compared to an identically sized Immobilized Cell Reactor (ICR) with no separation. The gas-phase separation of the product also allows fermentation of high inlet substrate concentrations. The model is used to determine the effects of reactor parameters on ICRS performance including temperature, pressure, gas flow rates, inlet substrate concentration, and degree of microbial product inhibition.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270703
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  • 168
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    An immobilized cell reactor with simultaneous product separation. II. Experimental reactor performance (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 943-952 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The simultaneous separation of volatile fermentation products from product-inhibited fermentations can greatly increase the productivity of a bioreactor by reducing the product concentration in the bioreactor, as well as concentrating the product in an output stream free of cells, substrate, or other feed impurities. The Immobilized Cell Reactor-Separator (ICRS) consists of two column reactors: a cocurrent gas-liquid “enricher” followed by a countercurrent “stripper” The columns are four-phase tubular reactors consisting of (1) an inert gas phase, (2) the liquid fermentation broth, (3) the solid column internal packing, and (4) the immobilized biological catalyst or cells. The application of the ICRS to the ethanol-from-whey-lactose fermentation system has been investigated. Operation in the liquid continuous or bubble flow regime allows a high liquid holdup in the reactor and consequent long and controllable liquid residence time but results in a high gas phase pressure drop over the length of the reactor and low gas flow rates. Operation in the gas continuous regime gives high gas flow rates and low pressure drop but also results in short liquid residence time and incomplete column wetting at low liquid loading rates using conventional gas-liquid column packings. Using cells absorbed to conventional ceramic column packing (0.25-in. Intalox saddles), it was found that a good reaction could be obtained in the liquid continuous mode, but little separation, while in the gas continuous mode there was little reaction but good separation. Using cells sorbed to an absorbant matrix allowed operation in the gas continuous regime with a liquid holdup of up to 30% of the total reactor volume. Good reaction rates and product separation were obtained using this matrix. High reaction rates were obtained due to high density cell loading in the reactor. A dry cell density of up to 92 g/L reactor was obtained in the enricher. The enricher ethanol productivity ranged from 50 to 160 g/L h while the stripper productivity varied from 0 to 32 g/L h at different feed rates and concentrations. A separation efficiency of as high as 98% was obtained from the system.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270704
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    Enzyme adsorption in porous supports: Local thermodynamic equilibrium model (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 961-971 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Enzyme adsorption from a finite bath (batch adsorption) onto porous spherical supports is investigated both experimentally and theoretically using β-galactosidase and Duolite ion-exchange resin as a model system. Efficient numerical techniques are presented that have been used in conjunction with a parameter estimation routine to evaluate adsorption isotherm constants. Results show that even for adsorption processes lasting almost 10 h, the majority of the enzyme is confined to the outer half of the support and, for high initial enzyme concentrations in the bath, this loading takes place as a slowly moving front. Information on the enzyme distribution has practical importance in the design of immobilized enzyme reactors that in previous works have almost always been analyzed assuming a uniform catalyst distribution.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270706
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  • 170
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    A new batch calorimeter for aerobic growth studies (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 996-1004 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A microcalorimeter for aerobic growth studies, derived from a Tian Calvet differential apparatus, was successfully constructed. The calorimetric vessel was a short cylinder, which permitted a good exchange between the surface area and the gas phase. The time constant of the calorimeter was 3.6 min and the sensitivity 234 V/W. The thermochemical aspect of the aerobic growth of Escherichia coli on succinate, acetate, and glucose was investigated. This analysis revealed that the contribution of biosynthetic reactions varied with the substrate used and strongly influenced the heat evolution. The experimental metabolic enthalpy change was in good agreement with the predicted value for succinate and glucose growth. To explain the discrepancy between the two values observed for acetate growth we suggest that acetate metabolism may generate a by-product which was not further oxidized.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270710
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  • 171
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    Conversion of cellulose to sugars by resting cells of a mesophilic anaerobe, Bacteriodes cellulosolvens (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 980-983 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: During the growth of Bacteroides cellulosolvens in media containing cellulose, the accumulation of unutilized sugars in the culture broth occurred mainly during the stationary phase of growth. Cells harvested during the stationary phase of growth continued to convert both cellulose and hemicellulose to cellobiose, glucose, and xylose. These three sugars caused feedback inhibition. Continuous removal of these sugars during the incubation of cells with cellulose at pH 5 accumulated ca. 32 g/L of sugars as compared to ca. 17 g/ produced under batch conditions of growth. Sugar formation by resting cells also increased with increasing cell concentration and did not require any nutrient.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270708
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  • 172
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    Dual aerobic hollow-fiber bioreactor for cultivation of Streptomyces aureofaciens (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1012-1020 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Streptomyces aureofaciens (ATCC 12416c) was grown in the interstitial region formed by a parallel arrangement of three hollow silicone tubules contained within a microporous polypropylene hollow fiber. Liquid-soluble nutrients were supplied by diffusion across the polypropylene fiber to the interstitial cell-containing region whereas air or oxygen was provided by diffusion from the silicone tubule lumina to the cell mass. In this bioreactor, S. aureofaciens grew to high cell densities (greater than 1011 cells/cm3) and the culture so-obtained continously synthesized the secondary metabolite tetracycline. The volumetric productivity of tetracycline based on the interstitial volume was 90 μg/ml/h and based on the total reactor volume was 5.5 μg/mL/h. The high surface area-to-volume ratio afforded by the cylindrical configuration together with spatially distinct conduits to continuously transport liquids and gases, each of which may be nutrients or products of biosynthesis, to or from a tissuelike cell mass provides an alternative to the conventional air- or oxygen-sparged fermentation vessel. High volumetric reactor productivities may be achieved by virute of the concentrated stationary cell mass and by the appropriate selection of fiber sizes and materials so as to ensure adequate supplies of liquid and gaseous substrates to, as well as removal of metabolites from, most cells in the culture. This reactor topology is quite general and may be adapted to most microbial as well as mammalian and plant cell systems.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270712
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    Enzymatic hydrolysis of cellulose in aqueous two-phase systems. I. partition of cellulases from Trichoderma reesei (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1036-1043 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The partitioning of endo-β-glucanase, exo-β-glucanase, and β-glucosidase from Trichoderma reesei QM 9414 in aqueous two-phase systems has been studied with the object of designing a phase system for continuous bioconversion of cellulose. The partitioning of the enzymes in two-phase systems composed of various water soluble polymeric compounds were studied. Systems based on dextran and polyethylene glycol (PEG) were optimal for one-sidedly partitioning the enzymes to the bottom phase. The influence of polymer molecular weights, polymer concentration, ionic composition of the medium, pH, temperature, and adsorption of the enzymes to cellulose on the enzyme partition coefficients (K) were studied. By combining the effects of polymer molecular weight and adsorption to cellulose, K values could be reduced for endo-β-glucanase to 0.02 and for β-glucosidase to 0.005 at 20°C in a phase system of Dextran 40-PEG 40000 in the presence of excess cellulose, At 50°C, K values were increased by a factor of two. In a phase system based on inexpensive crude dextran and PEG, the partition coefficient for endo-β-glucanase was 0.16 and for β-glucosidase was 0.14 at 20°C with excess cellulose present.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270715
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  • 174
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    Enzymatic hydrolysis of cellulose in aqueous two-phase systems. II. Semicontinuous conversion of a model substrate, solka floc BW 200 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1044-1050 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model substrate, Solka Floc BW 200, was semicontinuously hydrolyzed in an aqueous two-phase system based on crude dextran and polyethylene glycol over a period of more than 450 h. With an initial concentration of 75 g/L and intermittent addition of cellulose an average concentration of 50 g/L sugar was semicontinuously produced at dilution rates of 0.006-0.012 h-1. The conversion of substrate varied between 49 and 66%. The enzyme consumption measured as FPU/g reducing sugar (RS) produced could be reduced by a factor two when compared to a batch process since, in the aqueous two phase system investigated, the enzyme could be recycled two times.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270716
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  • 175
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    Simulation of CFSTR through development of a mathematical model for anaerobic growth of Escherichia coli cell population (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1051-1055 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A computer model is described that simulates a population of Escherichia coli B/r-A cells growing under anaerobic conditions. This population model is an ensemble of single-cell models. The ability of the model of predict the dynamic response of a cell population in a CFSTR to a change in feed flowrates or concentrations was investigated. With glucose as the limiting nutrient the feed concentration of glucose was shifted from 1.0 to 1.88 g/L. With a fixed concentration of glucose (1.0 g/L) step changes in residence time (4.1-1.95 h) were examined. The predicted changes of cell size distribution, substrate concentration, RNA content, and cell dry weight during the transition period compared reasonably well to those observed experiementally. We believe this model is the only model currently available that can make such predictions on an a priori basis.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270717
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  • 176
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    Improved rate of fumaric acid production by tweens® and vegetable oils in rhizopus arrhizus (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1067-1069 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270721
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  • 177
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    Separation of ethanol from ethanol - water mixture by reverse osmosis (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1081-1084 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270725
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  • 178
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    Enzyme reactor with knitted fabric made of poly(vinyl alcohol) superfine filaments (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1077-1080 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Various supports and bio-reactors have been proposed. Packed bed reactors with polymer material in granular shape are most often employed in both laboratory and industry. But they have a disadvantage related to an increase in pressure drop. We already developed filter paper composed of short cut pieces of superfine filaments (SFF). It shows high performance, but its hydrodynamic resistance increases when substrate solution passes through it. A new type of enzyme reactor equipped with knitted SFF has been proposed. In this reactor, substrate does not pass through the support but flows along the thin channel and parallel to the support. Therefore, it is able to maintain flow rate constant during a considerable period. The productivity of the reactor fairly increases by reducing the thickness of the channel because linear velocity increases with the reduction of the thickness and that contributes to the decrease in mass transfer resistance.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260270724
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    Masthead (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985) 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270801
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  • 180
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    Effects of aromatic compounds on hemicellulose-degrading enzymes in Aspergillus japonicus (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1095-1101 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aspergillus japonicus was grown in the presence of various aromatic compounds at 0.1 and 1 mg/mL, and extracellular xylanase and arabanase activities were measured. Some of the aromatic compounds tested, especially at the higher concentration, suppressed the appearance of hemicellulase activities, expressed as xylanase or arabanase. Vanillin at 1 mg/mL in the presence of either xylan or araban completely suppressed growth, and guaiacol and p-coumaric acid markedly inhibited the growth of A. japonicus. The effects of the aromatic compounds on the activity of crude enzyme preparations were also ascertained. In vitro arabanase activity was affected more than xylanase activity.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270802
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  • 181
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    A kinetic study of Saccharomyces strains: Performance at high sugar concentrations (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1108-1114 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Alcoholic fermentation represents a significant example of production of compounds utilizable as alternative energy sources. High ethanol concentration in the fermented wort is needed in order to reduce the energy consumption in the process of alcohol recovery. A particular Saccharomyces strain, of the oviformis species, obtained from fermented worts exhibiting high ethanol concentrations is studied and compared with a common S. cerevisiae strain in order to show its skill in fermenting very concentrated sugar solutions with an energy saving of ca. 10%.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270804
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  • 182
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    Modeling of enzyme immobilization in porous membranes (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1126-1135 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article deals with the mathematical modeling of the process of enzyme immobilization in porous membranes. During the initial period, an analytical solution is available to extract the rate constant for immobilization. Beyond this period, the model equations are solved numerically to yield the transient response of the enzyme concentration in the immobilizing solution and also the evolution of the enzyme loading profile inside the membrane. It is found that the immobilization practically ceases even through the attachment sites are still available within the membrane.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270807
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  • 183
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    Solid-state fermentation of sweet sorghum to ethanol in a rotary-drum fermentor (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1122-1125 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sugar compounds present in chopped solid-sweet sorghum particles were fermented to ethanol in a rotarydrum fermentor (RDF) using an ethanol tolerant yeast strain. The influence of rotational speed of the RDF on the rate of ethanol fermentation was investigated and compared with static flask experiments. The rate of ethanol formation decreased with increasing rotational speed. The maximum rate and extent of ethanol formation were ca. 3.1 g EtOH/L h (based on expressed juice volume) and ca. 9.6 g EtOH/100 g mash, respectively, at 1 rpm rotational speed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270806
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  • 184
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    An automatic method for on-line estimation of the photosynthetic rate in open algal ponds (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1136-1145 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An analytical model for dissolved oxygen concentration in an algal minipond was used to develop a new method for estimating, on-line, the net O2 production rate (OPR) of the biological process. The method was tested experimentally and was found to provide crucial information on the vitality of the biological process and to provide an early warning of a possible forthcoming collapse of the ecosystern. It is suggested that the newly developed model and measurement method could provide investigators with useful tools for optimization of algal cultivation in the laboratory and plant.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270808
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  • 185
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    Startup of anaerobic downflow stationary fixed film (DSFF) reactors (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1152-1165 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: One of the serious problems limiting the application of full-scale anaerobic fixed film processes is reactor startup. To better understand startup, studies with downflow stationary fixed film (DSFF) reactors were conducted to characterize the effects of influent concentration, support material, and surface-to-volume ratio on biofilm development and overall reactor performance. Materials with roughened surfaces gave the best startup performance and as expected increased surface area in the reactors led to more rapid increases in loading rates and higher ultimate loadings. Soluble influent COD concentrations between 5 × 103 and 2 × 104 mg/L influenced the rate of biofilm development. Lower COD concentrations resulted in faster development of the biofilm, even though ultimate loadings were not necessarily achieved as rapidly as in reactors fed higher strength wastes. No decrease in specific activity of the biofilms in each reactor was observed as the thickness of the biofilms increased to their maximum value at the ultimate loadings. The operation of reactors fed lower strength wastes was more stable than reactors receiving higher strength feeds at comparable loadings. Biofilm yield and activity, COD removals, suspended growth and activity, and other system parameters are discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270810
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  • 186
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    Recycle hollow fiber enzyme reactor with flow swing (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1185-1191 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The hollow fiber enzyme reactor with pulsation developed by Kim and Chang (1983) was operated in a differential mode by recycling a substrate solution, in order to assess the efficiency of ultrafiltration swing. The rates of lactose conversion by β-galactosidase contained in the shell side of the reactor were measured to determine the effects of recirculation rate, pulsation period, and amplitude. The conversion increased with the increase of recirculation flow rate and the amplitude while variation in period affected the conversion relatively little. The maximum increase of 113% in the activity was observed in the reactor with pulsation as compared to that without pulsation. The two-compartment model well described the experimental data obtained in this study. Square-wave pulsation was theoretically more effective in increasing conversion than sine wave pulsation. However, in experimental operation the damping effect of the hollow fiber wall narrowed the difference between these two wave forms.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270813
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  • 187
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    Fuzzy bioengineering models (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1146-1151 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A classical quantitative (analytical and/or statistical) analysis is not appropriate for some ill-defined and/or very complex bioengineering problems. Therefore, a new form of analysis using fuzzy mathematics has been developed. The fuzzy model can utilize semiqualitative and linguistic data which are to a certain level inconsistent. Bioengineering interpretation of the basic concept of fuzzy mathematics is given together with a numerical algorithm for a fuzzy evaluation of a model. A simple fuzzy model of a fermentor is studied in detail.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270809
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  • 188
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    Comparisons between cellulase production by Aspergillus fumigatus in agitated vessels and in an air-lift fermentor (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1166-1172 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aspergillus fumigatus was cultured in disc-turbine-agitated vessels and in an air-lift fermentor. In the agitated vessels the yield of cellulase was reduced when the agitation rate was increased, although extracellular protein levels rose. The enzyme complex itself was shown to be exceptionally stable under conditions similar to those in the agitated vessels, so probably shear damage to the mycelium had occurred, liberating intracellular contents. These appeared to contain an inhibitor that could be removed by fabricated inorganic protein absorbents, such as kieselguhr and alumina. However, the inhibitor was not likely to be protease, since only relatively low levels could be detected and its identity has not been established. The use of an air-lift fermentor avoided the shear effects due to use of the disc turbine agitator in the conventional fermentors, and yields of enzyme were then found to increase by about 20%, maximum yields being obtained at maximum KLa values.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270811
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  • 189
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    A growth model for the continuous microbiological leaching of a zinc sulfide concentrate by Thiobacillus ferrooxidans (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1173-1184 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The leaching of a zinc sulfide concentrate by Thiobacillus ferrooxidans was investigated in continuous stirred tank reactors. A mathematical model for the growth of T. ferrooxidans on this solid substrate is presented and tested. Experimental leaching studies were done using two reactors in series with and without recycle of solids from the outlet of the first reactor back to its inlet. The proposed model fits the authors' experimental data well. However, comparison of the parameters calculated with those calculated from the data of others showed that a wide variation can exist; thus, the parameters seem to depend on the nature of the substrate. The area occupied on the sulfide surface by a bacterium was found to be 5.4 μm2. The calculated maximum specific growth rates ranged from 0.20 to 0.31 h-1, and these values were dependent on whether they were observed in the first or second of the two reactors in series.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270812
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  • 190
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    Steady-state and transient behavior in microbial methanification: I. Experimental results (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1192-1198 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The process of methanification of volatile fatty acids (VFA) was studied to elucidate its kinetics. An upflow anaerobic sludge bed (UASB) system was used to perform the experiments. At residence times of less than 2.5 h the UASB system was found to exhibit hysteresis with respect to acetic and propionic acid consumption but not with respect to butyric acid consumption. These hysteretic effects could be attributed to the manner in which the various VFA-consuming cultures were structured inside the flocculated biomass in light of the cross-inhibitory effects of the acetic- and propionic-acid-consuming fractions of the total culture. (Butyric acid proved to be non-interactive.) Production of methane was found to respond almost instantaneously to changes in the inlet conditions of the UASB system. This indicated that methane is not primarily growth associated, as has often been assumed, but is related to changes in the culture's maintenance energy requirements. Reactor operation was found to be stable even when the concentration of each VFA in the feed was simultaneously changed by 50%. Even at very high organic throughput rates (35 kg COD/day m3-reactor) conversions of 82% were observed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270814
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  • 191
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    Immobilized live cell reactor dynamics following dilution rate shift to growth conditions: Cell synchrony effectsThe authors dedicate this paper to Professor Wolf R. Vieth on the occasion of his 50th birthday (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1208-1213 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Nutrient deprivation was used to synchronize an immobilized live cell culture of Acetobacter suboxydans. The substrate supply was increased by a step change in the dilution rate to the reactor. Oscillations in cell, substrate, and product concentrations were observed. A population balance model was developed to explain the observed reactor dynamics. Simulation results based on the model were used to substantiate the premise that cell synchrony is the likely phenomenon responsible for the observed oscillations. The implications of cell synchrony in immobilized cell systems are discussed briefly.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270816
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  • 192
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    Steady-state and transient behavior in microbial methanification: II. Mathematical modeling and verification (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1199-1207 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It has been shown that the Upflow Anaerobic Sludge Bed (UASB) system data reported earlier1 cannot be explained by simple Monod-type substrate consumption patterns. An autoinhibition model was also ruled out because the substrate concentration range over which hysteresis was observed was much larger than such a model would predict. However, propionic and acetic acids were found to inhibit each other's conversion machineries. Since in the UASB system the biocatalyst is flocculated, it was found that a model additionally incorporating this facet of the reactor set-up could explain the steady-state data very well. Using the parameters generated from steady-state data and data from butyric acid step change,1 i.e., the entire set of parameters (Table I), a very good agreement between predicted and observed data was found. International Mathematical and Statistical Libraries (IMSL) and Upjohn's NONLIN library combined with various root-finding and integrating subroutines were used for parameter estimation. The model thus described was used to predict the response of the UASB system when acetic acid and propionic acid influent concentrations were stepped-up/down. The agreement between the predicted and observed data was found to be excellent in each case during the step-up schedule. During the step-down the data seemed to indicate that the UASB system, like any other chemostat, responded faster than predicted. This could be due to the fact that when the culture has to “gear up” part of the lag time is the time required for the cell to produce the requisite amount of enzymes. In the case of “gearing down” this time is not required and the system responds faster.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270815
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  • 193
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    Invertase activity of intact cells of Saccharomyces cerevisiae growing on sugar cane molasses. I. Steady-state continuous culture tests (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1229-1235 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: During the steady-state continuous culture of Saccharomyces cerevisiae on sugar cane blackstrap molasses under different experimental conditions, oscillatory variations of the invertase activity of the intact yeast cells were observed. The continuous morphological changes of the cells wall and of the periplasmic space affecting the interaction between invertase and sucrose molecules could be responsible by the observed oscillatory phenomena. The average invertase activity at the steady state is linearly correlated to the cell's growth rate.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270819
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  • 194
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    An ultrafiltration membrane reactor for obtaining experimental reaction rates at defined concentrations of inhibiting sugars during enzymatic saccharification of alkali-pretreated sallow: Formulation of a simple empirical rate equation (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1328-1334 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of the enzymatic hydrolysis of sodium hydroxide-pretreated sallow were studied in an ultrafiltration membrane reactor in the presence of different concentrations of glucose. In the UF membrane reactor low-molecular-weight products were continuously removed at a low dilution rate and replaced by a buffer solution that contained different concentrations of glucose, which made it possible to keep the inhibiting product concentration constant throughout an experiment. The reaction rate was related to the degree of substrate conversion and a mathematical relationship was formulated that describes the influence of the product concentration on the rate coefficient.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270909
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  • 195
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    Effect of culture phasing and mannanase on production of cellulase and hemicellulase by mixed culture of Trichoderma reesei D 1-6 and Aspergillus wentii pt 2804 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1353-1361 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Significant increase in extracellular cellulase and hemicellulase activities was observed in the biosynthesis of cellulase enzyme in mixed culture fermentation of Trichoderma reesei D 1-6 and Aspergillus wentii Pt 2804 when the A. wentii inoculation was phased by 15 h. The optimal conditions of fermentation by the mixed culture have been established. Presence of mannanase has been found to affect the release as well as activity of cellulase enzyme produced in mixed culture.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270912
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  • 196
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    Biotransformation of 3-methoxy-8,14-seco-1,3,5(10),9(11) estratetraen-14,17-dione (secodione) to its 17β-hydroxy derivative (secol) using immobilized yeast cells (Pichia farinosa Y-118)CDRI Communication number 3509 (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1347-1352 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The yeast cells of Pichia farinosa Y-118 were immobilized in polyacrylamide gel and used for 17 β-oxidoreduction of secondione to secol. The loss of hydroxysteroid oxidoreductase activity of cells was found to be insignificant during immobilization. The preparation exhibited greater temperature stability as compared to free cells. The ratio of reaction volume to the volume of immobilized biocatalyst in the range 1.4-1.9 was found to be satisfactory for the reaction conditions studied. This ratio played a significant role in the stability of the catalyst particle, since beyond a critical value the disintegration of gel granules was rapid resulting in sharp decline of activity. The immobilized cell preparation could be used 50 times over a period of 100 days without loss of activity. However, the activity declined in further reuses, leaving the preparation 50 and 35% active after its 60th and 70th uses, respectively.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270911
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  • 197
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    Influence of medium and matrix composition on diffusivities in charged membranes (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1382-1384 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270916
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  • 198
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    Biological treatment specific for an industrial wastewater containing s-triazines (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1291-1296 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mixed cultures of bacteria grew in medium containing real s-triazine wastes as nitrogen source. About 80% of the s-triazine waste could be degraded as determined by HPLC and by measurements of dissolved nitrogen. The culture required an added carbon source in order to degrade s-triazines. A temperature optimum near 40°C was observed and a salt concentration above about 4% markedly retarded growth and the degradation of s-triazines. This system was examined as a biological treatment for wastes from syntheses of s-triazines.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270904
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  • 199
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    Role of cometabolism in biological oxidation of synthetic compounds (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1306-1311 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A significant portion of the total biodegradative activity toward synthetic compounds may involve cometabolism; thus, the latter represents an important type of microbial process. A mixed microbial population acclimated to highstrength industrial wastewater degraded about 90% of the organic carbon present in the wastewater. A reasonable agreement in the carbon balance provided clear evidence for the biodegradability of residual organic species. Based on the growth expression of Haldane to account for substrate inhibition, a substrate utilization model to quantify the role of cometabolism coupled with cellular maintenance is proposed. The kinetic parameters of the model have been estimated from experimental data. If the maintenance values are assumed negligible, as has been observed for wastewater systems, it is possible to quantify the magnitude of co-metabolism encountered in the biological oxidation of synthetic organic compounds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270906
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  • 200
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    Fermentation and recovery of the EcoRI restriction enzyme with a genetically modified Escherichia coli strain (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 1320-1327 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The fermentation and recovery of the EcoRl restriction endonuclease with a genetically modified Escherichia coli strain is investigated. Vast amounts of product could be obtained after cultivation in a 20-L computer-coupled pilot fermentor and purification of the recovered wet cells. It was found that in the end the product is at least inhibitory and probably lethal to the cells (the lethality has been proven with genetic experiments) so that optimum yield requires an optimized choice for the time instant of induction. Growth after induction and product formation require substantial amounts of oxygen, which must be supplied if a high population level is to be achieved. pH control may alleviate the burden of high oxygen supply. Quantitative assessment after the different purification stages indicate that approximately 15% active enzyme can be obtained from the total amount produced.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270908
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