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  • 1985-1989  (3,097)
  • 1830-1839
  • Biochemistry and Biotechnology  (3,097)
  • 201
    Electronic Resource
    Electronic Resource
    Hydrolysis of lactose in skim milk by immobilized β-galactosidase in a spiral flow reactor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1249-1257 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-galactosidase from Aspergillus Oryzae immobilized in a spiral flow reactor was used to effect the hydrolysis of the lactose component of skim milk. Residence time distribution measurements were used to assess the amount of longitudinal dispersion occurring as a consequence of the spiral flow pattern and the semiporous nature of the polymeric material used to construct the spiral. It was possible to model the flow conditions as tubular flow with a Peclet number that was a linear function of the reactor space time. Nonlinear regression methods were used to determine the kinetic parameters of three proposed enzymatic rate expressions. The best fit of the data was obtained using a rate expression containing separate terms for competitive inhibition of the reaction by both the a and β anomers of galactose. This kinetic model also incorporates the kinetics of the mutarotation between these forms. At 30°C and a space time of 7 minutes, 80% of the lactose present in skim milk can be converted to glucose and galactose.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331005
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  • 202
    Electronic Resource
    Electronic Resource
    Immobilization of endo-polygalacturonase from Aspergillus niger on various types of macromolecular supports (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1258-1266 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Endo-polygalacturonase (endo-PG) was immobilized on a wide range of natural and synthetic macromolecular supports and their modified derivatives representing many chemical classes, including esters, amides, phenols, alkyl- and arylamines, and carboxyl derivatives. The immobilization entailed methods of adsorption alone as well as covalent bond formation using glutaraldehyde or carbodiimide or via the diazo-coupling reaction. The most promising system proved to be immobilization on trimalehylchitosan (TMC) via adsorption followed by treatment with glutaraldehyde (GA). The binding capacity of the support is on the order of 13,000 IU/g, half of which is active. Various properties of immobilized endo-PG were evaluated. The optimum pH of the enzyme shifted to the alkaline side. The relative catalytic activity was considerably high even at room temperature and remained so above 70°C. The thermal stability at pH 3-4 was notably improved by immobilization, the half-time doubling. Finally, the apparent Km was greater for immobilized endo-PG than for native enzyme, while the Vmax was smaller for the immobilized enzyme.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331006
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  • 203
    Electronic Resource
    Electronic Resource
    Immobilized enzymes in reverse micelles: Studies with gel-entrapped trypsin and α-chymotrypsin in AOT reverse micelles (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1277-1282 
    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 α-chymotrypsin were immobilized by gelentrapment in polyacrylamide cross-linked with N,N1-methylenebisacrylamide. The immobilized enzymes are catalytically efficient in suspensions of reverse micelles formed in isooctane by bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and water. Both entrapped enzymes are stable in reverse micellar suspension at room temperature and pH 8.2 for 3 days and lose 30-40% activity after 1 week. The enzymes obey Michaelis-Menten kinetics in the investigated concentration range with Km values higher than those in solution. Activity of the enzymes is independent of the water content of the micellar solution. No shift in pH optimum was observed for immobilized trypsin activity toward Nα-benzoyl-L-arginine ethyl ester. The utility of the procedure, which combines the advantage of enzyme immobilization and enzymology in reverse micelles, is illustrated by an example of peptide synthesis. In particular, peptide synthesis (e. g., Z—Ala—Phe—Leu—NH2) using water-insoluble substrate has been performed with gelentrapped α-chymotrypsin in reverse micellar suspension with the advantage of efficient enzyme recycling.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331008
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  • 204
    Electronic Resource
    Electronic Resource
    Expression of β-lactamase by recombinant Escherichia coli strains containing plasmids of different sizes - effects of pH, phosphate, and dissolved oxygen (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 309-319 
    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 growth and synthesis of plasmid-encoded protein were studied for strains of recombinant E. coli JM103 which carried the β-lactamase gene on plasmids of different sizes. The plasmids used included the vector pUC8 and its recombinant derivatives containing varying-sized inserts of Drosophila DNA (not expressed in E. coli). Luria broth (LB) and a minimal medium (M9) supplemented in some cases with additional inorganic phosphate were used as growth media. There was no evidence of segregational instability in these experiments, where no antibiotic selection pressure was employed. Responses of the recombinant strains to variations in environmental parameters including pH, phosphate concentration in the medium, and aeration rate were examined. While the cell growth rate in LB decreased with pH in the range 7.0-8.0, the bulk β-lactamase activity was maximized at an intermediate pH. The recombinant cell growth rate decreases with increasing plasmid size in the minimal medium, while such decrease is not significant when a rich medium such as LB is used. There is an intermediate plasmid size in the range studied (2.7-8.7 kb), at which β-lactamase activity is maximum. While reduction in aeration rate (which determines the dissolved oxygen level) is detrimental for cell growth, it is beneficial for β-lactamase synthesis. The bulk β-lactamase activity therefore exhibits a maximum with respect to aeration rate. Cell growth and β-lactamase production are affected in a similar manner by phosphate concentration in the minimal medium and therefore both are maximized at the same phosphate concentration. This investigation demonstrates clearly how the production of a recombinant plasmid-encoded protein can be maximized by proper manipulation of culture conditions and how it is affected by plasmid size.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340306
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  • 205
    Electronic Resource
    Electronic Resource
    Fermentation of D-xylose, D-glucose, L-arabinose mixture by Pichia stipitis: Effect of the oxygen transfer rate on fermentation performance (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 398-402 
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340314
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  • 206
    Electronic Resource
    Electronic Resource
    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989) 
    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.260340401
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  • 207
    Electronic Resource
    Electronic Resource
    Removal of hydrogen sulfide from biogas by chemoautotrophic fixed-film bioreactor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 410-414 
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340317
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  • 208
    Electronic Resource
    Electronic Resource
    Continuous production of 3-fluoro-L-alanine with alanine dehydrogenase (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 394-397 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Alanine dehydrogenase catalyzed the conversion of 3-fluoropyruvate into 3-fluoro-L-alanine in the presence of NADH and ammonia. The optimum pH of the reaction was 7.8. The Km values of the enzyme for 3-fluoropyruvate, polyethylene glycol-bound NADH, and ammonia were 2.94, 0.56, and 105mM, respectively. 3-Fluoro-L-alanine was selectively and continuously produced from 3-fluoropyruvate and ammonium formate in an enzyme membrane reactor by the multienzyme reaction system of alanine dehydrogenase and formate dehydrogenase with a simultaneous coenzyme regeneration. The average conversion and the space-time yield were 73% and 75 g/L day, respectively, with operation of the reactor for 4 days. Alanine dehydrogenase and formate dehydrogenase consumed were 11, 370 and 22, 950 units/kg 3-fluoro-L-alanine, respectively. The cycle number was 3150 mol/mol NAD.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340313
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  • 209
    Electronic Resource
    Electronic Resource
    Lactose hydrolysis by immobilized β-galactosidase in capillary bed reactor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 438-446 
    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 hydrolysis of lactose by immobilized β-galactosidase was studied in a continuous-flow capillary bed reactor operating at 30°C. Solutions containing 50, 100, and 150 g lactose and 0.5 g sodium acetate/L were fed to the reactor. Lactose conversions ranging from 24% to greater than 99% were achieved at reactor space times ranging from 0.06 to 6.3 min. These conversion data were successfully modeled in terms of a plug flow reactor model and a form of Michaelis-Menten kinetics which included competitive inhibition by both the alpha and beta forms of galactose.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340404
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  • 210
    Electronic Resource
    Electronic Resource
    Desorption of Trichoderma reesei cellulase from cellulose by a range of desorbents (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 291-298 
    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 desorption of Trichoderma reesei cellulase from Avicel by a wide range of desorbents was measured. Emphasis was placed on desorption at alkaline pH. A maximum desorption of 65-68% Avicelase activity was achieved by contact with NaOH, pH 10.0, at 40°C for 5 min in the presence of 0.005% Triton X-100 or Tween 80. The design of a suitable desorption process using these conditions is discussed. Glycerol was also effective as a desorbent either alone or in combination with alkali and detergent. However, relatively high concentrations of glycerol were needed and the maximum desorption achieved, 68%, was not significantly greater than that with only alkali and detergent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340303
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  • 211
    Electronic Resource
    Electronic Resource
    Sulfide and glutaraldehyde resistant strains of Thiobacillus denitrificans (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 565-569 
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340417
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  • 212
    Electronic Resource
    Electronic Resource
    Ethanol production from starch by a coimmobilized mixed culture system of Aspergillus awamori and Saccharomyces cerevisiae (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 716-723 
    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 development of a coimmobilized mixed culture sys tem of aerobic and facultative anaerobic microorganisms in Ca-alginate gel beads and the production of useful metabolites by the system were investigated. A coimmobilized mixed culture system of Aspergillus awamori (obligate aerobe) and Saccharomyces cerevisiae (facultative anaerobe) in Ca-alginate gel beads was used as a model system, and ethanol production from starch by the system was used as a model production. Mold Asp. awamori is an amylolytic microorganism while yeast S. cerevisiae is an ethanol producer. The two microorganisms grew competitively in the oxygen-rich surface area of the gel beads because they had similar oxygen demands in aerobic culture conditions. Neither microorganism exhibited “habitat segregation” in the gel beads and leaked yeast cells grew aerobically without ethanol production in the broth. Ethanol productivity was low under these conditions.A more desirable coimmobilized mixed culture system of Asp. awamori and S. cerevisiae was established by adding Vantocil IB (a biocidal compound) to the production medium. The antimicrobial activity of Vantocil IB was more effective with S. cerevisiae than with Asp. awamori, so that a dense mycelial layer of Asp. awamori formed in the surface of the gel beads While S. cerevisiae grew densely in the more inner areas of the gel beads. Also, yeast cell leakace was repressed and ethanol productivity was improved. The system with Vantocil IB produced ethanol of 4.5 and 12.3 g/L from 16 and 40 g/L starch, respectively. A continuous culture using this system with Vantocil IB was also carried out, and a stable steady state could be maintained for six days without leakage of yeast cells and contamination. The selection of a factor suitable for producing “habitat segregation” enabled the development of a coimmobilized mixed culture system of an aerobe and a facultative anaerobe. In this study, total habitat segregation was used to denote a tendency to exhibit denser growth in different parts of one gel bead.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330609
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  • 213
    Electronic Resource
    Electronic Resource
    Growth and death in overagitated microcarrier cell cultures (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 731-744 
    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 effects of hydrodynamic forces on cell growth are investigated for animal cells growing on microcarriers. A reduction in net growth was observed with high levels of agitation. DNA measurements indicated that the reduction in net growth was due entirely to cell death, from hydrodynamic forces. No inhibition or enhancement of cell replication appeared to occur with high levels of agitation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330611
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  • 214
    Electronic Resource
    Electronic Resource
    Cultivation of hybridoma cells in continuous cultures: Kinetics of growth and product formation (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 724-730 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mouse hybridoma cells were grown in suspension in continuous stirred bioreactors. Cell growth, substrate utilization, and monoclonal antibody (MAb) production were studied using serum-free medium. Steady-state data were obtained at different dilution rates, between 0.012 and 0.039 h-1 Viability was profoundly affected by dilution rate, particularly near the lower end of the dilution-rate range investigated. MAb concentration and productivity went through a maximum with respect to dilution rate. Lactate yield on glucose declined with in creasing dilution rate. Experiments were carried out to study the effects of medium glucose concentration on cell growth, product formation, and lactate yield on glucose. Reduction of glucose concentration in the feed medium did not considerably affect cell density and MAb concentration in the culture, but lactate levels dropped sharply; lactate yield on glucose declined substantially, indicating alterations in cell metabolic path ways for energy metabolism. Optimization strategy for continuous cell culture is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330610
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  • 215
    Electronic Resource
    Electronic Resource
    Control of interspecies electron transfer flow during anaerobic digestion: Dynamic diffusion reaction models for hydrogen gas transfer in microbial flocs (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 745-757 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dynamic reaction diffusion models were used to analyze the consequences of aggregation for syntrophic reactions in methanogenic ecosystems. Flocs from a whey digestor were used to measure all model parameters under the in situ conditions of a particular defined biological system. Fermentation simulations without adjustable parameters could precisely predict the kinetics of H2 gas production of digestor flocs during syntrophic methanogenesis from ethanol. The results demonstrated a kinetic compartmentalization of H2 metabolism inside the flocs. The interspecies electron transfer reaction was mildly diffusion controlled. The H2 gas profiles across the flocs showed high H 2 concentrations inside the flocs at any time. Simulations of the syntrophic metabolism at low substrate concentrations such as in digestors or sediments showed that it is impossible to achieve high H2 gas turnovers at simultaneously low steady-state H2 concentrations. This showed a mechanistic contradiction in the concept of postulated low H2 microenvironments for the anaerobic digestion process. The results of the computer experiments support the conclusion that syntrophic H2 production may only be a side reaction of H2 independent interspecies electron transfer in methanogenic ecosystems.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330612
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  • 216
    Electronic Resource
    Electronic Resource
    Sandy alumina as substrate for economic and highly efficient immobilization of β-glucosidase (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 777-779 
    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: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330615
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  • 217
    Electronic Resource
    Electronic Resource
    Competitive yeast fermentation with selective flocculation and recycle (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 767-776 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous fermentations were carried out involving competition between two strains of Saccharomyces cerevisiae. One of the strains has a lower specific growth rate and is very flocculent, whereas the fastergrowing strain is nonflocculent. The product stream from the chemostat was fed into an inclined settler where the flocculent strain was partially separated from the nonflocculent strain as a result of the higher sedimentation rate of the flocculent cells. The underflow from the inclined settler, which was concentrated and enriched with flocculent cells, was recycled to the chemostat. When no recycle was used, the fastergrowing, nonflocculent yeast rapidly overtook the culture. With selective recycle, however, the experiments demonstrated that the slower-growing flocculent yeast could be maintained as the dominant species. A theoretical development is also presented in order to describe the competition between two strains in the bioreactor-settler system. The concept of selective recycle via selective flocculation and sedimentation offers a possible means of maintaining unstable recombinant microorganisms in continuous fermentations.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330614
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  • 218
    Electronic Resource
    Electronic Resource
    Electrophoretic and enzymatic studies on the crude extracellular enzyme system of the cellulolytic bacterium Cellulomonas sp. ATCC 21399 (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 59-64 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cellulomonas sp. ATCC 21399 produced extracellular enzyme activities against Avicel, H3PO4-swollen Avicel, carboxymethylcellulose, (1-3, 1-4)-β-D-heteroglucan, xylan, galactomannan, and amylose drying growth on microcrystalline cellulose. No extracellular cellobiase activity was produced. Crossed immunoelectrophoresis of the crude extracellular enzyme system revealed 15 immunologically distinct immunoprecipitates. The immunoprecipitates of endoglucanase A, endoglucanase B and the xylanase appeared heterogeneous with several optima, whereas the immunoprecipitates of endoglucanase C and the amylase appeared homogeneous. The heterogeneity of endoglucanase A, endoglucanase B and xylanase was also visualized using electrofocusing-immunoelectrophoresis. Electro-focusing could resolve the activity against carboxymethylcellulose into six peaks, whereas only one peak of activity against Avicel was observed. The later peak coincided with the major peak of activity against carboxymethylcellulose with isoelectric point between pH 4.0-5.0.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340108
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  • 219
    Electronic Resource
    Electronic Resource
    Optimization of fed-batch penicillin fermentation: A case of singular optimal control with state constraints (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 72-78 
    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 determination of the optimal feeding profile of a fed-batch fermentation requires the solution of a singular optimal control problem that is often complicated by constraints imposed on the state variables. Such constraints can be a maximum allowable biomass concentration beyond which oxygen transfer is severely limited or maximum substrate concentration to avoid side reactions. Due to these state constraints and the singular nature of the problem, complete solutions are especially hard to obtain and almost nonexistent in the literature. In this work the feed concentration is employed as the control variable in a solution approach that first determines the optimal reactor substrate concentration and subsequently solves for the feed concentration profile that results in the optimal reactor profile. Calculations for the fed-batch penicillin fermentation indicate sharp increases in productivity over frequently employed strategies.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340110
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  • 220
    Electronic Resource
    Electronic Resource
    Mode of action of endopolygalacturonase immobilized by adsorption and by covalent binding via amino groups (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 79-85 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Action pattern of endopolygalacturonase (E.C.3.2.1.15) immobilized by adsorption on porous powdered poly(ethyleneterephthalate) and covalently bound via amino groups on poly(2, 6-dimethyl-p-phenyleneoxide) and poly(6-caprolactame), respectively, were investigated in suspension and packed columns using polymeric and oligomeric D-galactosiduronates as substrates. The covalent binding invariably led to a lowering of randomness of degradation of high-molecular substrates and loss of specificity of (3 + 1) splitting of tetra(galactosiduronic acid), typical of the free enzyme. In the adsorbed endopolygalacturonase the degree of randomness of degradation of D-galacturonan and Km,app value were dependent on the substrate transfer; the former parameter increased, the later decreased with increasing flow-rate of the substrate through the immobilized enzyme bed. The action pattern on low-molecular substrates was not altered. The changes in action pattern of the covalently immobilized endopolygalacturonase are ascribed to sterical limitations resulting from a binding of the enzyme molecule in the proximity of its active site. In endopolygalacturonase bound to the support by hydrophobic interactions external diffusion effects are regarded the factors governing the enzyme action.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340111
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  • 221
    Electronic Resource
    Electronic Resource
    Biochemical limits to microbial growth yields: An analysis of mixed substrate utilization (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 799-799 
    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.260330620
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  • 222
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    Subsite mapping of Aspergillus niger glucoamylases I and II with malto- and isomaltooligosaccharides (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 681-688 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Glucoamylase, industrially derived from Aspergillus niger, was chromatographically separated into forms I and II and purified to near homogeneity. Preparations were proved to be free of D-glucosyltransferase by electrophoretic and differential inhibition tests. Maximum rates and Michaelis constants were obtained for both glucoamylases I and II with maltooligosaccharides from maltose to maltoheptaose and with isomaltooligosac-charides from isomaltose to isomaltohexaose. Subsite maps were calculated from these kinetic data and were not significantly different for the two forms. Subsites in both forms had lower affinities for D-glucosyl residues contained in isomaltooligosaccharides than for D-glucosyl residues in maltooligosaccharides.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260340512
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989) 
    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.260340601
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    Desorption of cobalt-laden algal biosorbent (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 815-822 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Following an effective accumulation of cobalt by nonliving algal biomass of Ascophyllum nodosum, the desorption release of the metal from the biosorbent was examined using H2SO4, HCl, NH4OH, KHCO3, EDTA, KSCN, KCl, and CaCl2 solutions. The solution of CaCl2 (0.05M) in HCl appeared to be the best eluant capable of desorbing more than 96% of the sequestered cobalt at the optimum pH 2-3. The optimum solid-to-liquid ratio was more than 10 with the cobalt reuptake capacity of the biosorbent undiminished. The effect of temperature on the elution process and the elution rate was not significant up to 60°C. The infrared (IR) spectra of the native and the eluted biomass did not show significant differences. The electron micrographs of the algal biomass taken after washing it with the CaCl2 (0.1M) eluant solution indicated no damage to the cells and cell walls, while strong acid, alkaline, and KSCN treatment resulted in some changes in the cellular structure. The kinetics of the cobalt stripping process was quite rapid. The required contact time for the complete metal removal from the biomass was shorter than 2 h, even for the highest levels of cobalt initially deposited on the biomass.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330704
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  • 225
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    Effect of environmental growth conditions on plasmid stability, plasmid copy number, and catechol 2,3-dioxygenase activity in free and immobilized Escherichia coli cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 801-808 
    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 order to better understand the high plasmid stability in immobilized recombinant E. coli cells, the effects of dilution rate on the pTG201 plasmid stability, the copy number, and the catechol 2,3-dioxygenase (encoded by XyIE gene) production were, at first, studied in free E. coli W3101 continuous cultures in minimal media. It was found that decreasing specific growth rate increased the plasmid copy number and the catechol 2,3-dioxygenase activity but the stability decreased. In continuous culture with immobilized cells, an increase was shown in plasmid copy number and catechol 2,3-dioxygenase activity probably due to the distribution of growth in the gel beads. Besides mechanical properties of gel beads which may allow limited cell divisions, the increase in plasmid copy number is involved in enhanced plasmid stability in immobilized cells. In the same way, an experiment conducted in LB medium dealing with competition between pTG201-free and pTG201-containing E. coli B cells was described. It was shown that the competition was not more pronounced in gel bead compared to a free system. The effects of nutritional limitations on pTG201 plasmid stability and catechol 2,3-dioxygenase activity during chemostat cultivations in free and immobilized E. coli B cells were also investigated. It was found that immobilization of cells increased the stability of pTG201 even under glucose, nitrogen, or phosphate limited cultures. However in the case of magnesium depleted culture, pTG201 was shown to be relatively instable and a decrease in viable cell number during the immobilized continuous culture was observed. By contrast to the free system, the catechol 2,3-dioxygenase activity increased in immobilized cells under all culture conditions used.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330702
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  • 226
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    Destruction and formation of toxins by one bacterial species affect biodegradation by a second species (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 832-838 
    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 Pseudomonas able to grow on phenol or p-nitrophenol (PNP) were isolated from sewage. Pseudomonas sp. PN101 mineralized and formed nitrite from PNP but did not mineralize phenol, and Pseudomonas sp. PH111 mineralized phenol but not PNP. Phenol increased the lag period before Pseudomonas sp. PN101 grew on and mineralized PNP, but this toxicity was reduced by inoculation of the medium with Pseudomonas sp. PH111. PNP inhibited growth of Pseudomonas sp. PH111 and slightly increased the length of the acclimation period for the mineralization of phenol by the bacterium. Inoculation of Pseudomonas sp. PN101 into solutions containing PNP and phenol increased the lag period prior to growth of Pseudomonas sp. PH111 on phenol and markedly lengthened the lag period for its mineralization of phenol. Coinciding with this delay in the onset of phenol degradation was the accumulation of an organic compound formed from PNP by Pseudomonas sp. PN101. This compound was not mineralized by the phenol-degrading bacterium. The data suggest that bacteria may interact during the decomposition of chemical mixtures by destroying or by forming toxins that affect the biodegradation of individual components of those mixtures.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330706
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  • 227
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    Transcription from plasmid genes, macromolecular stability, and cell-specific productivity in Escherichia coli carrying copy number mutant plasmids (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 902-908 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments were performed to evaluate, qualitatively and quantitatively, the adaptation of Escherichia coli to plasmid maintenance and cloned gene expression. Experimental findings indicate that the metabolic response to low plasmid levels is an increase of the biosynthetic capacity of both transcription and translation. At high copy number levels the gene-specific transcription rate continues to increase but the stability of plasmid-derived mRNA drops sharply. Protein levels are maintained, but translation efficiency decreases. These results indicate that cellular biosynthetic capacity may not be limiting productivity in recombinant systems. If macromolecular stability is the bottleneck, then current efforts to increase gene expression that focus on enhancing synthesis rates will be ineffective.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260340704
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  • 228
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    Biotransformation of benzaldehyde by Saccharomyces cerevisiae: Characterization of the fermentation and toxicity effects of substrates and products (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 933-941 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Although higher initial rates of phenylacetyl carbinol formation were observed in fermentations containing a high starting benzaldehyde level, a massive reduction in yeast viability was observed resulting in early cessation of production formation. Pulse feeding to maintain lower benzaldehyde concentrations resulted in a lower initial reaction rate, but prolonged yeast viability and the biotransformation. This resulted in higher overall product tilers. As benzaldehyde concentration was increased, yeast growth rate was reduced (0.5 g/L), inhibited (1-2 g/L), or cell viability reduced (3 g/L). Benzaldehyde appeared to alter the cell permeability barrier to substrates and products. Reductions in yeast biomass levels and especially protein and lipid content were observed during the biotransformation. The effects of benzaldehyde and reaction products on yeast pyruvate decarboxylase and alcohol dehydrogenase stability were determined. Homogenized yeast cells produced similar phenylacetyl carbinol levels to whole yeast only if supplemented with thiamine pyrophosphate and magnesium.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260340708
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    Forced-flow bioreactor for sucrose inversion using ceramic membrane activated by silanization (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 856-861 
    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 forced-flow enzyme membrane reactor system for sucrose inversion was investigated using three ceramic membranes having different pore sizes. Invertase was immobilized chemically to the inner surface of a ceramic membrane activated by a silane - glutaraldehyde technique. With the cross-flow filtration of sucrose solution, the reaction rate was a function of the permeate flux, easily controlled by pressure. Using 0.5 μm support pore size of membrane, the volumetric productivity obtained was 10 times higher than that in a reported immobilized enzyme column reactor, with a short residence time of 5 s and 100% conversion of the sucrose inversion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330709
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  • 230
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    Viscous reduction of turbulent damage in animal cell culture (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 862-872 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Animal cells are exposed to turbulent fluid flow in many cell culture processes. If the turbulence in the flow is sufficiently strong, the cells will be damaged or killed by fluid-mechanical forces. Through an increase in viscosity, the turbulence can be damped and the hydro-dynamic damage can be reduced. In this article, new experimental results are presented which illustrate the protective effect of thickening agents. The results follow the prediction of a model based on Kolmogorov's theory of universal equilibrium in turbulent flow fields.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330710
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  • 231
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    Simultaneous hydrolysis and fermentation of raw dent and high lysine corn and their starches (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 906-911 
    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.260330714
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  • 232
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    The use of reverse micelles for the simultaneous extraction of oil and proteins from vegetable meal (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 1140-1146 
    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 method for the simultaneous extraction of oil and proteins from vegetable meals is presented. The method uses hydrocarbon reverse micelles, so that the oil is extracted directly into the hydrocarbon phase and the proteins are solubilized in the water pools of the reverse micelles. The surfactant used is bis (2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane at variable w0 values (w0 measures the amount of water in the system, where w0 = [H2O]/[AOT]). A comparison with the usual extraction methods is offered. It is shown that with the micelle system the extraction of oil is as large as with the usual methods, and it is independent of w0. However the amount and type of proteins extracted depends strongly on w0. At w0 values below 6, no protein and only low molecular weight compounds (i.e. chlorogenic acid) are extracted, at larger water content (i.e. by increasing the dimension of the micelle water pool), also proteins are solubilized in a significant amount and with a molecular weight which increases by increasing W0. The protein solubilized in the microemulsion system can be recovered into an aqueous phase with a back-transfer step.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340904
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  • 233
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    Acetone-butanol-ethanol (ABE) production in a novel hollow fiber fermentor-extractor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 1158-1166 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Acetone-butanol-ethanol (ABE) production by immobilized C. acetobutylicum cells is studied in a novel microporous hollow fiber based tubular fermentor-extractor. The solvent 2-ethyl-l-hexanol is used for in situ dispersion-free extraction of products. A mathematical model for simultaneous fermentation and extraction of the products has been investigated. The predicted as well as experimental data follow the same trend. The experimentally observed value of total solvent productivity increased by more than 40% as a result of in situ solvent extraction.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340906
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    Experimental investigation of G6P production and simultaneous ATP regeneration by conjugated enzymes in an ultrafiltration hollow-fiber reactor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 369-379 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Enzymatic synthesis of glucose 6-phosphate from glucose and ATP catalyzed by glucokinase from B. stearothermophilus and enzymatic regeneration of ATP from ADP and acetyl phosphate catalyzed by acetatekinase from B. stearothermophilus were simultaneously performed in an Ultrafiltration hollow-fiber reactor of the multitubular heat-exchanger type. Experimental results of space-time yield, the conversion, and ATP recycle number were in good agreement with the theoretical predictions based on the simple analytical model developed in the preceding article. The best results for space-time yield and conversion were Ys = 1.97 mol/m3 h and X = 92.8%, respectively, under the same conditions, and the best result for the ATP recycle number was NR = 2130 under conditions different from those above. However, Ys = 1.72 mol/m3 h, X = 81.2%, and NR = 1620 were the results when the space-time yield, conversion, and recycle number were at the highest in combination under the same conditions. Results of long-term operation showed that the apparent remaining activity of the enzyme system was ca. 55% after continuous operation for 16 days, the decrease in the enzyme activity being faster than that expected from their half-life times determined individually in the homogeneous system.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340310
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  • 235
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    Purification of wheat germ agglutinin using affinity flocculation with chitosan and a subsequent centrifugation or flotation step (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 387-393 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Affinity purification is by tradition almost equivalent to affinity chromatography. In this report, a purification process is described in which the affinity interaction is performed in free solution. A precipitation step follows, thereby separating the affinity bound material from free. Chitosan is used as a natural polyligand rich in N-acetyl-D-glucosamine and is, because of its specificity, used in affinity precipitation of wheat germ agglutinin (WGA). The polyligand is soluble at pH below 6.5 and precipitates at higher values, thus coprecipitating associated WGA. A process was developed where the overall yield of WGA was 70% and the final product gave a single band on SDS-PAGE. The process was also run on a larger scale, where even affinity flotation was included in the study as an alternative way to harvest the precipitate. Scaling up the affinity precipitation was a very easy task.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340312
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  • 236
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    Chemostat study of kinetics of human lymphokine synthesis in recombinant Escherichia coli (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 415-421 
    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.260340318
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  • 237
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    A flow injection analysis system for fermentation monitoring and control (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 423-428 
    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 automated analysis system for on-line fermentation monitoring is presented. The modular system consists of an in-line sterilizeable crossflow microfilter, a selection valve that allows injection of sample or standards, a degassing unit, a dilution module, and a FIA manifold with a spectrophotometric UV/VIS detector. In the dilution module samples are conditioned and diluted depending upon concentration of analyte and the working range of the analyzer. Methods for the monitoring of glucose, ethanol, ammonia and phosphate are described. Results from the monitoring of glucose and their use in fermentation control are presented. The maximal analysis frequency is 30 samples per hour including the dilution of 1 : 200. Detection limits are 5 mg/L for ethanol and glucose, 1 mg/L for phosphate and 50 mg/L for ammonia.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340402
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  • 238
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    Compartment model concept used in the design of fermentation with recombinant microorganisms (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 478-486 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Simple models are of great value in order to simulate cell dynamics, and a class of potentially useful models are the so-called compartment models, which are a simple extension of the unstructured approach. Compartment models have earlier been used with great success to describe cell dynamics. In this article the authors present a 4-compartment model that is able to describe a majority of the observations that have been made through fermentations with recombinant microorganisms. The compartment model is especially suited for description of dynamic changes in plasmid copy number, e.g., runaway replication. Simulation of batch fermentation with runaway conditions corresponds very well with experimental results. Finally the model is used in the design of an optimal fermentation strategy in a CSTR.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340407
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  • 239
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    Analysis of a framework using material balances in metabolic pathways to elucidate cellular metabolism (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 496-501 
    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 framework using material balances in metabolic pathways to study cellular metabolism is examined and the results are discussed. Rate measurements on extracellular compounds alone were found to be not always sufficient to validate proposed unique intracellular mechanisms. The conditions to delineate among candidate mechanisms based solely on extracellular measurements are established. The number of half reactions comprising the reaction network is found to be an important parameter.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340409
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  • 240
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    Xylose fermentation by yeasts. 5. Use of ATP balances for modeling oxygen-limited growth and fermentation of yeast Pichia stipitis with xylose as carbon source (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 509-514 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Kinetic studies are presented for the growth and fermentation of the yeast Pichia stipitis with xylose as the carbon source. Ethanol is produced from xylose under anaerobic as well as under oxygen-limiting conditions but only at dissolved oxygen concentrations up to 3 μmol/L Maximum yields and production rates were obtained under oxygen-limiting conditions, where the xylose metabolism may be considered to be consisted of three different components (assimilation, respiration, fermentation). The contribution of each pathway is determined by the availability of oxygen and the energy yield of each pathway. In order to describe the course of oxygen-limited fermentations, a mathematical model has been developed with the assumption that growth is coupled to the energy production. The resulting model requires only four independent parameters (Yx/O2, YATPmax, mATP, and P/O). These parameters were estimated on the basis of eight separate batch fermentations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340411
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  • 241
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    Performance of a membrane reactor for cellobiose hydrolysis (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 955-962 
    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 continuous enzymatic hollow fiber reactor (HFR), obtained by immobilizing cellobiose active cells into the shell side of hollow-fiber modules, was studied. The HFR yield was monitored by glucose analysis resulting from hydrolysis of cellobiose. The residence time of substrate in the bioreactor to obtain convenient hydrolysis yields was calculated from tests carried out by varying the reactor dilution rate in the range 0.001-0.004 L/min. The glucose yield was measured for 300 h (continuous substrate flux). The yield decreased from 40 to 15%. This decrease was due to the loss of specific activity in the operating conditions and to the pressure drop increase from 0.2 to 1.7 atm. The pressure drop increase is in turn dependent on the cell loading (0.2-2.1 g dry cell) and the substrate flux.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330804
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  • 242
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    Immobilized enzyme cellulose hollow fibers: III. Physical properties and in vitro biocompatibility (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 1383-1390 
    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 initial testing of the safety of a cellulose-heparinase hollow fiber device was assessed with respect to physical properties and in vitro biocompatibility. The material cleared urea and creatinine without passing albumin, even at high flow rates. The clearance of urea and creatinine by cellulose-heparinase was equal or slightly reduced in comparision to the cellulose device. The cellulose-neparinase device tolerance to now rates was also unchanged. In addition, scanning electron microscopy of the lumen established the uniformity of the material. The analysis of clearance rates and the scanning electron micrographs show there to be no damage to the cellulose membrane after tresyl chloride activation and heparinase immobilization. The investigation of biocompatibility in an in vitro test system with whole human blood indicated that there were no significant changes in the biocompatibility of cellulose with bound heparinase. There was no change in the level of red blood cells, white blood cells, or platelets over the course of in vitro whole blood perfusion through cellulose or cellulose-heparinase hollow fiber devices. Low levels of plasma hemoglobin and complement activation were observed with cellulose and cellulose-heparinase devices. Thus, the cellulose hollow fibers can be functionalized without any changes in in vitro performance.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260341106
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    α-Factor directed expression of the human epidermal growth factor in Saccharomyces cerevisiae (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 976-983 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Expression kinetics of the human Epidermal Growth Factor (hEGF) from the α-factor prepro region in a 2-μm based plasmid was studied in Saccharomyces cerevisiae. Production of hEGF was highly medium de pendent as a chemically defined, nonenriched media had a significantly lower yield than did enriched media. Also cells grown on yeast nitrogen base without amino acids with casamino acids degraded the hEGF after cell growth as opposed to a yeast extract, peptone, and dextrose (YEPD) medium, which elicited no measurable extracellular proteolysis of the hEGF. α-factor directed production kinetics of hEGF on the YEPD medium were growth associated, secretion limitations and extracellular degradation were negligible, and the hEGF was nearly 100% selectively secreted. With sufficient agitation, shake flask experiments were representative of aerated controlled batch fermentations. No effect of high cell density was observed on cell growth or hEGF production kinetics. The hollow fiber bioreactor had no direct effect on the substrate or protein yields of S. cerevisiae, however the low oxygen transfer capacity of the membrane was not sufficient to support respiration.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330806
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    Transient kinetics of hybridoma growth and monoclonal antibody production in serum-limited cultures (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 984-990 
    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 quantitative study of the influence of initial serum concentration on hybridoma growth rate, maximum viable and total cell yield, and specific antibody production rate is presented. The specific growth rate varied in a Monod fashion with initial serum levels (2-10% FCS), giving Km = 1.6 v/v% and μmax = 0.92 d-1. The maximum cell yields (total and viable) were linear with initial serum level, indicating stoichiometric as well as kinetic limitation by serum component(s). The specific antibody production rate for each individual run fitted well to a non-growth-associated model. However, the non-growth-associated parameter varied monotonically with initial serum concentration, suggesting the catalytic role of serum component(s) in antibody production. Also, glutamine was utilized inefficiently, with at least a third of it secreted back into the culture supernate in the form of glutamate. While very simple model equations describe the specific growth and product formation rate for an individual batch run, the larger picture indicates need for a more detailed unstructured or structured model.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330807
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  • 245
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    Induction of T4 DNA ligase in a recombinant strain of Escherichia coli (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 991-998 
    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 cell growth and foreign protein production, as well as factors affecting protein stability, were studied and optimized in batch and fed-batch fermentations of a recombinant strain of Escherichia coli. The pL promoter from bacteriophage lambda under the control of a temperature-sensitive cl represser, with the entire construct integrated into the E. coli chromosome through the use of a defective bacteriophage lambda lysogen, was used to direct the synthesis of T4 DNA ligase. The biphasic fermentations consisted of a primary growth phase at 30°C followed by an induction phase which was initiated by shifting the temperature to 42°C. In the fed-batch fermentations, additional nutrients were added at the time of initiating induction. Maintenance of sufficiently high concentrations of the organic substrates (glucose and casamino acids) during the induction phase was required for continued cell growth at 42°C. Such growth was essential for T4 DNA ligase formation and in vivo stability. Hence, fed-batch fermentations produced the highest yield of the foreign protein Commensurate with providing lower total amounts of substrates. In such cases, high cell densities (6 g dry wt/L) with substantial intracellular levels of T4 DNA ligase (4.6% total cellular protein, or 2.7% of the dry biomass) were achieved.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330808
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  • 246
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    Periodic operation of a continuous culture of Baker's yeast (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 741-749 
    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 possibility of enhancing the biomass productivity of a continuous culture of Saccharomyces cerevisiae growing on a glucose-limited medium is addressed. An unstructured Monod-type model is first identified using steady-state data. The culture is subjected to step changes in dilution rate, and it is seen that the Monod model is unable to predict even qualitatively the dynamic response of the culture. Incorporation of a time delay allows significant improvement in the transient fit. It is found that the culture has a time lag of about 3 h in adapting its growth rate. Cycling the dilution rate with a period of 3 h leads to substantial improvement in the average biomass productivity.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340603
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  • 247
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    A new graphical method for determining parameters in Michaelis-Menten-type kinetics for enzymatic lactose hydrolysis (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 763-773 
    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 graphical method was developed to determine the kinetic parameters in the Michaelis-Menten-type equation. This method was then applied to studying the kinetics of lactose hydrolysis by Aspergillus niger β-galactosidase. In this study, the reaction temperature ranged between 8 and 60°C, and the initial lactose concentration ranged between 2.5 and 20%. A kinetic model similar to the conventional Michaelis-Menten equation with competitive product inhibition by galactose was tested using this graphical method as well as a nonlinear computer regression method. The experimental data and the model fit together fairly well at 50°C. However, a relative large disparity was found for reactions at 30°C. A three-parameter integrated model derived from the reversible reaction mechanism simulates the experimental data very well at all temperatures studied. However, this reversible reaction model does not follow the Arrhenius temperature dependence. Nevertheless, reaction rate constants for the proposed model involving the enzyme-galactose complex (in addition to the Michaelis complex) as an intermediate in lactose hydrolysis follow the Arrhenius temperature dependence fairly well, suggesting that this model can be best used for describing the enzymatic lactose hydrolysis. The lack of fit between the model predictions and data may be largely attributed to the effects of galactose mutarotation and oligosaccharide formation during lactose hydrolysis.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340606
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  • 248
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    Measurement of enzyme reaction rates using advanced pH control system: Application of repetitive PF system (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 794-803 
    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 aim of this article is to develop the on-line measurement system of enzyme reaction rates, using an advanced pH controller, which is called a repetitive PF(Programmed Controller/Feedback Compensator) System. In the esterolysis reaction of the N-acetyltyrosine ethyl ester by α-chymotrypsin, the enzyme reaction rate could be calculated from the amount of base required for keeping the pH constant. The proposed controller has a learning mechanism in which the knowledge is obtained from the former results of the repetition, and pH was controlled much more successfully by the proposed repetitive PF System than by the conventional on-off controller, PI controller, and the adaptive controller. The enzyme reaction rate could be evaluated each time as accurately as possible based on the result of the controlled batch reaction. Using Lineweaver-Burk plots of the estimated reaction rates, kinetic parameters, such as the enzyme activity and Michaelis-Menten constant, could be estimated more accurately and from fewer experiments by the repetitive PF system than by initial reaction rates using on-off pH-stat.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340609
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  • 249
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    Analysis of the biomass quality and photosynthetic efficiency of a nitrogen-fixing cyanobacterium grown outdoors with two agitation systems (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 819-824 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The efficiency of two different agitation systems (airlift and paddlewheel) in the biomass photoproduction of a nitrogen-fixing filamentous blue-green alga was evaluated outdoors, and the elemental and molecular composition of the cells grown with each system was analyzed. With the paddlewheel system, the productivity values achieved were over 30% higher than with the airlift system, both in summer and winter. In this last season, a conversion efficiency of total solar energy into stored biomass energy of 3.3% was estimated for the paddlewheel system. Moreover, the algal cells grown with this system exhibited a higher net protein (58.9% of dry weight) and nitrogen (11.3%) content than those grown with the airlift device, with an estimated nitrogen fixation rate of more than 2 g N m-2 day-1. These advantages of the paddlewheel system make this procedure more appropriate for the large-scale photoproduction of nitrogen-fixing blue-green algae outdoors.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340611
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  • 250
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    Influenc of pH on the growth and ethanol production of free and immobilized Saccharomyces cerevisiae cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 882-884 
    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.260340620
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  • 251
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    Reduced product formation following perturbation of ethanol- and propionate-fed methanogenic CSTRs (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 885-895 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Energetic analysis was applied to reduced product formation following perturbation of ethanol- and propionate-fed methanogenic continuous stirred tank reactors (CSTRs). Formation and dissipation of longer-chained n-carboxylic acids corresponded with the variation in Gibbs free energy change associated with beta-oxidation reactions. Formation appeared to occur from acetate and propionate by reductive back-reactions, made energetically favorable by elevated hydrogen partial pressure (PH2), and possibly mediated by biosynthetic enzymes. The formed longer-chained acids dissipated when the PH2 fell and equilibrium shifted to favor beta-oxidations. n-Propanol was found to be produced from propionate in a coupled ethanol oxidation/propionate reduction reaction, mediated by ethanol-oxidizing organisms during high rates of ethanol utilization and elevated PH2. When PH2 declined, n-propanol was oxidized back to its precursor propionate. Both reaction energetics and intracellular diffusion of the electron carrier may effect transient mediation of this coupled reaction.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340702
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989) 
    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.260330901
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  • 253
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    Immobilization of an autotrophic bacterium by coculture with floc-forming heterotrophs (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), 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
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330817
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  • 254
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    Affinity-Specific protein separations using ligand-coupled particles in aqueous two-phase systems: I. Process concept and enzyme binding studies for pyruvate kinase and alcohol dehydrogenase from Saccharomyces cerevisiae (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1081-1088 
    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 process using ligand-coupled particles in aqueous polyethylene glycol-dextran two-phase polymer systems was developed to achieve a highly selective, scaleable biochemical separation process. Product protein is bound to the ligand-coupled particles that quantitatively distribute to the polyethylene glycol-rich upper phase. Other proteins and contaminants partition preferentially to the dextran-rich lower phase.The process offers significant advantages over affinity partitioning here the ligand is coupled to the backbone of a polyethylene glycol polymer. These advantages include a much wider diversity of ligands that can be coupled to particles and more effective confinement of the ligand in the process. Affinity partition with ligands coupled to particles is more amenable to scale-up than is affinity chromatography. A variety of commercially available Sepharose-based particles are suitable for this process. Homogenates from Saccharomyces cerevisiae, which is genetically altered to overproduce pyruvate kinase, and Cibacron blue F3G-A-coupled Sepharose particles are used as a model system for the process. Binding studies with/without aqueous two-phase systems show that the formation of a two-phase system after the adsorption equilibrium is reached does not affect the apparent dissociation constant. Binding of protein to ligand-coupled particles is more rapid in single-phase systems than in the polymer two-phase system. Single-phase binding eliminates the mass transfer resistance associated with redistribution of product protein from the dextran-rich bottom phase to the polyethylene glycol-rich top phase.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330902
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    Mechanism of thermoinactivation of immobilized glucose isomerase (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1104-1111 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Irreversible thermoinactivation of immobilized glucose isomerase from Streptomyces olivochromogenes has been mechanistically investigated at the pH-optimum of enzymatic activity (pH 8.0). Ligands (high fructose corn syrup and the competitive inhibitor xylitol) greatly stabilize the immobilized enzyme at high temperatures. At 90°C in the presence of 2M xylitol, irreversible inactivation of immobilized glucose isomerase is caused by deamidation of its asparagine/glutamine residues. On the basis of the data obtained, it appears that the time-dependent decay of glucose isomerase activity in industrial bioreactors is brought about by oxidation of the enzyme's cysteine residue and/or heat-induced deleterious reactions with high fructose corn syrup or its impurities.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330905
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  • 256
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    Solubilization of fish proteins using immobilized microbial cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1098-1103 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cells of Bacillus megaterium, Aeromonas hydrophila, and Pseudomonas marinoglutinosa were immobilized in calcium alginate. The immobilized cells secreted protease when held in fish meat suspension in water. The enzyme synthesis by the entrapped cells was supported by small amounts of soluble nutrients present in the meat. The secreted protease solubilized the fish meat, solubilization being optimum at pH range of 7.5 to 9.5 and at 50°C. Under these conditions immobilized B. megaterium was most efficient giving 30% solubilization of the meat, followed by A. hydrophila (18%), while immobilized P. marinoglutinosa was less effective. The optimum ratio of fish meat to beads was about 4:3 for B. megaterium and A. hydrophila. The beads had a storage life of 30 days at 4°C. The results suggested potential for use of immobilized microbial cells having extracellular protease activity to enhance solubility of waste proteins. A prototype reactor with beads holding assembly was fabricated which could recover the beads from the meat slurry after the treatment.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330904
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  • 257
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    A mathematical model for the growth of a single cell of E. coli on a glucose/glutamine/ammonium medium (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1117-1126 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Extension of a single cell model of E. coli B/r to make predictions of culture response to variations in glutamine/glucose/ammonium ion concentrations is described. A biphasic glutamine transport system, a nitrogen metabolism scheme that includes glutamate dehydrogenase (GDH), glutamine synthetase/glutamate synthase (GS/GOGAT), the glutaminase routes, and a transaminase mechanism for glutamine carbon usage are added to the prototype model. The predictions of the extended model with regard to nutrient concentrations and cell size compare well with the experimental data and the prototype model predictions, demonstrating the capability of the integrated kinetic model to illustrate important enzymological interactions in a biological system. The discrepancies between the experimental data and the model predictions on growth yield suggest that a more detailed regulatory system of the TCA cycle is required for a more accurate energy budget.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330907
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  • 258
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    The use of cellulases from a β-glucosidase-hyperproducing mutant of Trichoderma reesei in simultaneous saccharification and fermentation of wheat straw (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1112-1116 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conidia of the cellulolytic strain Trichoderma reesei F522 were mutagenized with UV irradiation and N-methyl|-N′-nitro-N-nitrosoguanidine (NTG). A visual agar plate detection system was developed, using esculin and ferric ions, to identify mutants of T. reesei with increased β-glucosidase activity. Selected mutants were tested for production of extracellular cellulases in shake flasks on autohydrolyzed wheat straw as carbon source. The most active mutant V-7 showed about 6-times higher activity of β-glucosidase than the parent strain F-522, whereas the filter paper degrading and endo-1,4-β-D-glucanase activities increased by 45% and by almost 31%, respectively. Cellulase preparations obtained from the parent and mutant strains were then used along with Kluyveromyces fragilis cells for ethanol production from ethanol-alkali pulped straw in the simultaneous saccharification and fermentation (SSF) process. From 10% (w/v) of straw pulp (dry matter), 2.5% (w/v) ethanol was obtained at 43°C after 48 h using cellulase derived from the parent strain of T. reesei. When the β-glucosidase-hyperproducing mutant V-7 was employed, the ethanol yield in the SSF process increased to 3.4% (w/v), the reaction time was shortened to 24 h and no cellobiose was detected in straw hydrolyzates.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330906
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  • 259
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    Immobilized enzyme cellulose hollow fibers: I. Immobilization of heparinase (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 1366-1373 
    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 immobilization of heparinase to tresyl-chloride-activated cellulose hollow fibers for the removal of heparin from the bloodstream was examined. Whole blood can be circulated through cellulose hollow fibers without hemolysis and the tresyl chloride chemistry provides a strong linkage which limits the release of the enzyme from the support. The tresylation and immobilization methods were modified and optimized to improve the heparinase activity retained by cellulose. Pretreatment of the hollow fibers with 0.05/V sodium hydroxide increased the degree of tresylation and the immobilization yield by a factor of five. The use of triethylamine as the organic base in the tresyl chloride activation resulted in threefold greater activity retention by the support than when pyridine was used. Together, sodium hydroxide pretreatment and triethylamine enhanced the activity retained by cellulose to 26.2 ± 7.0% of that bound to the support. The activity retention was also a function of the technique used for immobilization. The best results were achieved when the enzyme was applied to the activated fibers once every 12 to 24 h for a total of four times. The active enzyme loading on the fibers was 0.3 mg heparin degraded/h cm2 when 4.5 μg protein/cm2 was bound to the fibers.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260341104
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    In vivo nuclear magnetic resonance analysis of immobilization effects on glucose metabolism of yeast Saccharomyces cerevisiae (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1283-1289 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fermentation rates and intracellular compositions have been determined for alginate-entrapped Saccharomyces cerevisiae and for identical cells in suspension. Glucose uptake and ethanol and glycerol production are approximately two times faster in immobilized cells than in suspended cells. Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy of fermenting immobilized and suspended cells shows differences in intermediate metabolite levels such as fructose-1,6 diphosphate, glucose-6-phosphate, and 3-phosphoglycerate and in internal pH. Carbon-13 NMR shows an increase in polysaccharide production. These data suggest that immobilization has accelerated the rate of glucose transport or of glucose phosphorylation. These effects of immobilization upon cell metabolism are observed in a very short period of time under conditions in which negligible DNA, RNA, or protein synthesis takes place.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331009
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  • 261
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    Design of a lamella settler for biomass recycling in continuous ethanol fermentation process (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1296-1305 
    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 design and application of a settler to a continuous fermentation process with yeast recycle were studied. The compact lamella-type settler was chosen to avoid large volumes associated with conventional settling tanks. A rationale of the design method is covered. The sedimentation area was determined by classical batch settling rate tests and sedimentation capacity calculation. Limitations on the residence time of the microorganisms in the settler, rather than sludge thickening considerations, was the approach employed for volume calculation. Fermentation rate tests with yeast after different sedimentation periods were carried out to define a suitable residence time. Continuous cell recycle fermentation runs, performed with the old and new sedimentation devices, show that lamella settler improves biomass recycling efficiency, being the process able to operate at higher sugar concentrations and faster dilution rates.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331011
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  • 262
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    Improved method for preparing high maltose conversion syrups (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 299-303 
    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 improved method is presented for producing high maltose conversion syrups from liquefied and raw starch. It comprises saccharifying the starch at higher temperatures than presently used with environmentally compatible thermostable β-amylase and other thermostable enzymes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340304
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  • 263
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    Theoretical analysis of G6P production and simultaneous ATP regeneration by conjugated enzymes in an ultrafiltration hollow-fiber reactor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 357-368 
    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 performance of an ultrafiltration hollow-fiber reactor, in which the enzymatic synthesis of glucose 6-phosphate from glucose and cofactor ATP and the enzymatic regeneration of ATP from ADP and acetyl phosphate are performed simultaneously, was analyzed theoretically. A simple analytical model in which the liquid flowing in the fiber tubes is assumed to be plug flow, and the radial concentration gradients in the tube and shell sides are both neglected, could simulate the reactor performance with satisfactory accuracy. The simulation elucidated the effects of the reactor configurations and various operational conditions on glucose conversion, ATP recycle number, and space-time yield. If the fiber tubes, through which the permeability of the relevant components such as substrates is high, were packed as much as possible in the reactor, good reactor performance could be expected. Furthermore, with a sufficiently high enzyme concentration, low ATP concentration in the feed solution, and appropriate space velocity, good space-time yield with high glucose conversion and with very high ATP recycle number is theoretically possible.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340309
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  • 264
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    Reduction of sulfur dioxide by Desulfovibrio desulfuricans in co-culture with fermentative heterotrophs (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 405-409 
    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.260340316
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  • 265
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    Cross-flow membrane microfiltration of a bacteriol fermentation broth (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 447-466 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Although cross-flow membrane filtration is a very attractive option for harvesting cells and recovering enzymes from cell homogenates, the process is not without its problems. Foremost of these is the deposit of dissolved and suspended solutes onto the membrane surface during operation. The formation of these dense and sometimes compressive sublayers (often called cakes) offers additional resistance to axial and permeate flows and often affects the retention characteristics of the process. In view of the complex nature of the sublayer formation process and its sensitivity to cross-flow velocity, this investigation was undertaken to determine the main factors responsible for the decline in performance during the harvesting of B. polymyxa broth by membrane microfiltration. System parameters varied include axial flow rate, concentration of cells, proteins and other components in the feed, membrane materials (ceramic, polypropylene, and stainless steel), and cleaning methods. To help explain the observed results, a new mass transport model - the solids flux model - based on the assumptions that back migration of particles from the sublayer or membrane surface is negligible and that particles that reach the solid-solution interface attach (stick) completely, is tested. Using a variety of diagnostic methods, magnesium ammonium phosphate precipitate is formed during steam sterilization of the medium and is implicated as the major foulant in this study.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340405
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    Semicontinuous cultivation of Digitalis lanata cells: Production of β-methyldigoxin in a 300-L airlift bioreactorDedicated to Dr. O.-H. Volk on the occasion of his 85th birthday. (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 502-508 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Selected Digitalis lanata cell lines cultivated in 1-L shake flasks or 20-L airlift bioreactors converted β-methyldigitoxin into β-methyldigoxin with almost no side reactions. This biotransformation process was optimized with regard to substrate supply and culture medium composition, and was then scaled up to a volume of 210 L using a 300-L airlift bioreactor. A semicontinuous process was developed in which 513.3 g β-methyldigoxin were produced after 89 days of cultivation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340410
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    Interaction of infectious viral particles with a quaternary ammonium chlorid (QAC) surface (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 639-646 
    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 antiviral activity of a surface-bonded quaternary ammonium chloride (QAC) was examined in this study. The mechanism of inactivation was elucidated by a combination of infectivity assay, radioactive labeling assay, and sedimentation analysis. Although the virions are still infectious when attached onto the chemically modified surface, we found these viruses are inactivated if they are eluted from the surface. The inactivation is caused by the disruption of the viral envelope with subsequent release of the nucleocapsid. No evidence indicates the released nucleocapsid is further disrupted. An enveloped virus shows a much higher affinity for the QAC-treated surface than a nonenveloped one due to hydrophobic interaction. The QAC-treated beads can effectively remove the enveloped viruses at low protein concentrations. The titer of herpes simplex virus was reduced by a factor of nearly 5 logarithm units in a 0.5 wt % bovine serum albumin solution with less that 10% protein loss. However, the presence of proteins in the solution reduced both the rate and capacity of this nonspecific adsorption-inactivation process. As a consequence, the removal efficiency is relatively poor in solutions with high protein content.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340508
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    Retention of plasmid bearing cells by immobilization (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 717-724 
    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.260340516
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  • 269
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    Influence of diffusion on first-order deactivation of microheterogeneous enzyme samples (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 725-730 
    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.260340517
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  • 270
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    Hydrodynamics and mass transfer in Aspergillus niger fermentations in bubble column and loop bioreactors (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 731-740 
    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 influence of Aspergillus niger broth rheology, bioreactor geometry, and superficial gas velocity on the volumetric liquid phase oxygen transfer coefficient (kLaL), riser gas holdup (εGR), and circulating liquid velocity (uLR) was studied in a bubble column (BC) and two external-circulation-loop airlift (ECLAL) bioreactors. The results are compared to those of previous studies on homogeneous fluids and in particular with a recent study on non-Newtonian carboxymethylcellulose (CMC) solutions conducted in the same contactors used for the A. niger fermentations. As expected from the CMC-based studies, in the heterogeneous broths of A. niger εGR, kLaL, and uLR decreased with increasing broth apparent viscosity; εGR and kLaL decreased with increasing downcomer-to-riser cross-sectional area ratio, Ad/Ar, whereas uLR increased with increasing Ad/Ar. Gas holdup data in the airlift fermentations of A. niger were well predicted by the CMC-based correlation. However, the CMC-based correlations produced conservative estimations of kLaL and overestimates of uLR compared to the observed values in the A. niger broths.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340602
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    Study of gaseous substrate fermentations: Carbon monoxide conversion to acetate. 2. Continuous culture (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 785-793 
    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 of gaseous substrates such as CO, H2, and CO2 may be performed in a continuous stirred tank reactor, as well as the traditional batch reactor. In this article, the conversion of carbon monoxide by Peptostreptococcus productus is demonstrated in a stirred tank reactor under both mass transfer-controlled and nonmass transfer-controlled conditions. Utilizing a non-steady-state procedure, intrinsic rates are evaluated under non-mass transfer-controlled conditions in a time period of only 5-6 hours. A steady-state procedure was used to evaluate CSTR performance under mass transfer-controlled conditions. The mass transfer coefficient was calculated, followed by the development of a model to predict CSTR behavior for this gas phase substrate.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340608
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    Dependence of in vivo inactivation kinetics of gramicidin S synthetase on cell physiology (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 34 (1989), S. 1037-1044 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gramicidin S synthetase, the enzyme complex catalyzing the biosynthesis of the antibiotic gramicidin S in Bacillus brevis, is subject to O2-dependent in vivo inactivation during exponential aerobic growth after reaching a peak in specific activity. The five amino acid substrates of the synthetase are capable of stabilizing its activity to varying degrees in whole cells shaken aerobically. Depending on the time of cell harvesting before, during, or after the peak in intracellular gramicidin S synthetase specific activity, the enzyme has a long, medium, or short half-life, respectively. The kinetic profiles of gramicidin S synthetase in B. brevis cells indicate that both the kinetics of synthetase loss and the degree of its amino-acid-mediated stabilization are a strong function of the cells' physiological development.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260340803
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    Shear breakage of nylon membrane microcapsules in a turbine reactor (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 95-103 
    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 breakage of nylon membrane microcapsules is proposed as a new method to study and quantify shear effects in biological systems. A critique of this method shows that a narrower particle size distribution may be an important improvement in the breakage study as well as breakage control in many bioreactor and biotechnological applications. In a turbine reactor, it was shown that the primary process which determines the microcapsule breakage is the shear effect. The breakage kinetics are first order with regard to the microcapsule concentration. The breakage kinetic constant was ob served to be dependent on the temperature and the particle size, and proportional to the average shear rate and the third power of the turbine angular velocity. Decrease of the breakage kinetic constant with temperature can be explained by a decrease of fluid viscosity and a change in nylon membrane properties. An increase in the breakage kinetic constant with the microcapsule diameter can be due to a lowering of internal pressure and a reduction of the membrane resistance with size. Proportionality between the breakage kinetic constant and the shear rate shows that shear is the main process which leads to microcapsule breakage. The additional intervention in the shear rate expression of the turbine angular speed in the form of the turbine and particle velocities, results in the dependence of the breakage kinetic constant on the third power of the angular velocity.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330113
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    Use of immobilized trypsin for semisynthesis of human insulin (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 126-128 
    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.260330116
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    Simplified models for packed-bed biofilm reactors (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 164-172 
    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 a packed-bed biofilm reactor two reactor models are proposed. One model is for the limiting case of a biofilm with a constant biofilm thickness in which diffusion within the biofilm is shown to be negligible. The second model assumes that the thickness of the biofilm is limited by the concentration of substrate within the biofilm. The analytical solutions for these reactor models are shown to agree very well with the numerical solutions to the exact differential equations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330205
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    Cell growth and α-amylase production characteristics of Bacillus amyloliquefaciens (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 197-206 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Growth and α-amylase production characteristics of Bacillus amyloliquefaciens strain F (ATCC 23350) in batch cultures are examined using glucose or maltose as the carbon source. While the cell growth is rapid when glucose is used as the carbon source, higher cell mass, higher total and specific enzyme activities, and higher enzyme production rates are obtained when maltose is used as the carbon source. The overall specific enzyme activity decreases with an increase in the initial concentration of carbon source. The oxygen requirement and carbon dioxide generation vary linearly with the maximum amount of cell mass produced. For experiments conducted using glucose as the carbon source, the kinetics of cell growth and glucose consumption are described using a special form of the Vavilin equation. For a given amount of initial carbon source, the enzyme synthesis capability is retained by the microorganism, although at a substantially reduced level, under severe oxygen limitation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330209
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  • 277
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    Protein fractionation by three phase partitioning (TPP) in aqueous/t-butanol mixtures (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 221-228 
    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: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330213
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  • 278
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    The immobilization of penicillin G acylase on chitosan (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 242-246 
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330217
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    New sensor allowing continuous water activity measurement of submerged or solid-substrate fermentations (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 266-271 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Water activity of the substrate is an important and acute factor for growth as well as for metabolic production of microorganisms or for biocatalyst systems. A sensor has been designed in order to control this parameter on-line during submerged and solid-substrate fermentations. This sterilizable sensor allows the measurement of the relative humidity of the atmosphere in a small chamber by means of a capacitive element separated from the medium by a thin ethylenepolytetrafluoride membrane. For high aw values (〉0.90) a sequential circulation of a dried gas prevents the sensor saturation. Measurements are rapid and accurate, and control of the water activity of a fermentation medium has been carried out for 5 days using this sensor.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330304
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    Modeling of contact-inhibited animal cell growth on flat surfaces and spheres (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 300-305 
    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 of contact-inhibited growth of cells on flat and spherical surfaces is presented. It shows that contact inhibition does not significantly affect the calculated growth rate of cells unless they are allowed to multiply a large amount from the original seeding density. Microcarriers seeded at low densities require long times to reach confluence because contact inhibition becomes important. In systems with both growth and separate cell death, the equilibrium fraction of holes in the confluent monolayer is below 8% if the death rate is less than half the growth rate, but increases rapidly as the death rate increases from that value.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330308
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  • 281
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    Dual substrate removal by an axenic bacterial culture (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 327-337 
    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 pure bacterial culture capable of utilizing either L-lysine or 2-chlorophenol (2-CP) as sole carbon source was isolated and used in continuous culture experiments to determine its response to dual substrate limitation by those two compounds. Dilution rate and feed composition were each set at three levels in a two factorial experimental design. The total chemical oxygen demand (COD) of the feed was fixed at 225 mg/L and its composition was varied by changing the ratio of lysine to 2-CP. The effects of the two independent variables (dilution rate and feed composition) on the concentrations of cells, lysine, COD, and dissolved organic carbon (DOC) in the reactors were systematic whereas the effects on the 2-CP concentration were less predictable. The concentrations of the two substrates responded to the two independent variables in a complex interactive manner which is not explained by existing models for dual, substitutable substrates. Rather, the results suggested that the prediction of the fate of a single organic component in a reactor receiving a multicomponent feed is a very difficult task.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330312
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    Kinetics of the α-amylase of Schwanniomyces castellii (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 369-373 
    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.260330317
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    Novel technique for investigation and quantification of bacteriol leaching by Thiobacillus ferrooxidans (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1196-1204 
    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, efficient, and simple technique for the in situ study and quantification of the heterogeneous Bacteriol activity and the Bacteriol degradation of metal sulfides by Thiobacillus ferrooxidans is presented. It consists of exposing an ultrathin (300-2500 Å) metal sulfide layer, FeS2 in the experiments, to Thiobacillus f. grown in Touvinen media and visually following the Bacteriol attack and development of Bacteriol corrosion patterns under a light microscope. The uniform pyrite layer, partially transparent for visible light, permits the optical characterization of Bacteriol attack in remarkable detail. Several open or little understood questions concerning Bacteriol leaching, such as those on the kinetics of adhesion, the interfacial Bacteriol reproduction, the density of surface active bacteria, and the rate and morphology of sulfide degradation can also be studied. The degree of Bacteriol activity can be distinguished on the basis of development of variable sizes of spots and halos around Bacteriol cells produced by light passing through differently sized corrosion pits. The information obtained and identification of microorganisms has additionally been accentuated by immunofluorescence techniques (FA). It is concluded that the described method can be developed as a convenient testing and control technique for use in mine laboratories and bioleaching operations.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bit.260330916
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    Selective adsorption/desorption of nucleic acids on submicron-sized polymeric particles (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1205-1209 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: DNA can be removed or separated by the selective adsorption/desorption on positively charged submicronsized polymeric particles (SSPP). The selective adsorption of DNA, in the presence of protein, on positively charged SSPP was accomplished by increasing the concentration of potassium phosphate or sodium phosphate. The adsorption of DNA was not affected by the concentration of potassium phosphate or sodium phosphate up to 1.2M. On the other hand, the adsoprtion of a protein (bovine serum albumin) was completely impeded by 170mM potassium phosphate. DNA adsorbed on SSPP could be desorbed by increasing the concentration of NaCl or KCl, thus it can be recovered. DNA desorbed from SSPP when the concentration of NaCl or KC was higher than 0.6M. A complete desorption of DNA was achieved at the concentration of NaCl or KCl above 1.2M.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330917
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    Dynamic modeling of immobilized cell reactor: Application to ethanol fermentation (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1317-1323 
    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 mathematical model has been developed for the unsteady-state operation of an immobilized cell reactor. The substrate solution flows through a mixed-flow reactor in which cells immobilized in gel beads are retained. The substrate diffuses from the external surface of the gel beads to some internal location where reaction occurs. The product diffuses from the gel beads into liquid medium which flows out of the reactor. The model combines simultaneous diffusion and reaction, as well as cell growth, and it can predict how the rates of substrate consumption, product formation, and cell growth vary with time and with initial conditions. Ethanol fermentation was chosen as a representative reaction in the immobilized cell reactor, and numerical calculations were carried out. Excellent agreement was observed between model predictions and experimental data available in the literature.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331014
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    A criterion for selecting fermentation stoichiometry methods (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1347-1349 
    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.260331018
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989) 
    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.260331101
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    Enhancement of cellulase production by immobilization of Trichoderma reesei cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1358-1362 
    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: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331021
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    Kinetics of whey-lactose acidogenesis (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 623-630 
    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 mixed-culture anaerobic conversion of lactose to organic acids in a bench-scale continuous-flow stirredtank fermentor is considered. The major acidogenic end-product distribution with respect to the dilution rate are presented. A Monod chemostat model is employed to describe a microbial growth, and the influence on pH of the estimated model parameters is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330516
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  • 290
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    Fermentation data analysis and state estimation in the presence of incomplete mass balance (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 613-622 
    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 method is developed for identifying measurement errors and estimating fermentation states in the presence of unidentified reactant or product. Unlike conventional approaches using elemental balances, this method employs an empirically determined basis, which can tolerate unidentified reaction species. The essence of this approach is derived from the concept of reaction subspace and the technique of singular value decomposition. It is shown that the subspace determined via singular value decomposition of multiple experimental data provides an empirical basis for identifying measurement errors. The same approach is applied to fermentation state estimation. Via the formulation of the reaction subspace, the sensitivity of state estimates to measurement errors is quantified in terms of a dimensionless quantity, maximum error gain (MEG). It is shown that using the empirically determined subspace, one can circumvent the problem of unidentified reaction species, meanwhile reducing the sensitivity of the estimates.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330515
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  • 291
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    Two-Level factorial screening of new plasmid/strain combinations for prodution of recombinant-DNA products (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1393-1399 
    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 treats the basic problem of selection of experimental conditions for microbiological experiments for evaluation of newly isolated bacterial strains, mutants, or plasmid/strain combinations. For this purpose shake flask experiments in a 210-4confounded factorial design at resolution IV with four blocks of 16 flasks were used. The design was used for testing of two new strain/plasmid combinations (E. coli MT 102/403-SD2 and W 3110/403-SD2) i.e., both strains with the same plasmid 403-SD2. Both strains were integrated in the design, so both strains were tested with nine factors (temperature, aeration, glucose, initial pH, pH regulation, reduced aeration, chloramphenicol, acetate, and glycerol). With both strains the interaction between initial pH and reduced aeration had a significant influence on the yield of the recombinant-DNA product nuclease. There was more than a factor of 10 between lowest and highest yield of product. In this interactive system the strains reacted differently. MT 102/403-SD2 had highest yields at high initial pH (8.4) and no reduction in aeration, whereas W 3110/403-SD2 had highest yields of nuclease at low initial pH (7.4) and reduced aeration (rubber stopper inserted after cultivation for 12 h). These data (and previous work) clearly demonstrate that it is impossible to suggest a simple set of experimental conditions for testing of new plasmid/strain combinations. It is clear that the exclusive application of a standardized growth technique e.g., LB-medium at 37°C at an unspecified and uncontrolled aeration level, may lead to wrong conclusions on properties and potentials of now plasmid/strain combinations and may lead to rejection of useful strains or plasmids.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331105
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  • 292
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    A new method for the adaptive determination of optimum pH and temperature (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1419-1424 
    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 adaptive control algorithm for the on-line determination of optimal temperature or pH for biomass production in a continuous fermentor is presented. The algorithm requires no prior information and uses a dynamic Hammerstein model to identify parameters and to estimate an optimal steady-state control value. A check of the estimated performance measure second derivative is included to ensure that the target extremum is an optimum. The process is driven towards this optimum with a variable step size that depends on the quality of the on-line identified model. Numerical simulations are performed on a dynamic chemostat model that incorporates a metabolic time delay. The algorithm successfully finds the optimum temperature or pH values and maintains the reactor at the optimum steady state.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260331109
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  • 293
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    Effects of strain and fermentation conditions on production of cellulase by Trichoderma reesei (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 650-656 
    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.260330519
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  • 294
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    Aromatic aldehydes as substrates for yeast and yeast alcohol dehydrogenase (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 657-660 
    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: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330520
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  • 295
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    Masthead (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989) 
    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.260330601
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  • 296
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    Kinetic model of hydrocortisone 1-en-dehydrogenation by Arthrobacter globiformis (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 661-667 
    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 kinetic model of the hydrocortisone-to-prednisolone transformation by Arthrobacter globiformis is constructed using the experimental data obtained in studies of this process. Besides adequately describing experimental data, the model allows one to determine the relation between hydrocortisone oxidation and the level of endogenous substrates in bacterial cells, and the relation between the saturating concentration of hydrocortisone in the enzymic system of bacteria and the content of endogenous substrates in their cells, as well as the regulation of the transmembrane potential and the activation by the uncouplers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330602
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  • 297
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    Biofilm development in laboratory methanogenic fluidized bed reactors (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 687-693 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Biofilm development on sand with different heterogeneous inocula was studied in laboratory-scale methanogenic fluidized bed reactors. Both the course of biofilm formation during reactor start-up and the bacterial composition of newly developed biofilms at steady-state were found to be similar irrespective of the type of inoculum applied. Biofilm formation proceeded according to a fixed pattern that could be subdivided in three consecutive phases, designated as the lag phase, biofilm production phase, and steady-state phase. Methanogenic activity and biomass content of the fluidized bed granules were found to be accurate parameters of the course of biofilm formation. More indirect parameters monitored did not give unambiguous results in all instances. The composition of the newly developed biomass as assessed on the basis of potential methanogenic activities on different substrates and of the concentration of specific methanogenic cofactors was consistent with electron microscopic observations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330605
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  • 298
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    Combined rapid-steam hydrolysis and organosolv pretreatment of mixed southern hardwoods (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 681-686 
    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 types of pretreatments are used for biomass conversion of woods. The major objective of most pre treatments is to increase the susceptibility of cellulose and lignocellulose material to acid and enzymatic hydrolysis. In this study, southern mixed hardwoods were pretreated by combined rapid steam hydrolysis (RASH) and organosolv methods. It was found that the major factor in the pretreatment was the RASH temperatures. The organosolv temperature had only a minor effect on the reactivity of the final product. The enzymatic rate studies indicated that the RASH process helps in increasing the accessibility of cellulose to enzymatic hydrolysis and increased the amount of soluble lignin While the organosolv process only removed solubilized lignin. Another effect of the combined treatment was the decreasing of the enzymatic rate relative to a single RASH pretreatment. All hemicellulose is lost during these pretreatments. Three alcohols (methanol, ethanol, and butanol) were studied using a combined RASH organosolv process. At lower temperatures there were small differences between the alcohols; however, at higher temperatures all alcohols were equally effective. At longer RASH times, the percentage of glucose in the final product, as well as the amount of solubilized lignin, increased. However, the longer RASH times led to a decrease in enzymatic rates, Organosolv residence time studies of 15, 30, and 45 minutes displayed little effect on the product. Various wood-to-solvent ratios and water-to-alcohol ratios had very little effect on the yield of products. The stability of RASH treated material be fore organosolv process was studied under various storage conditions. The storage conditions had no apparent effect on the product.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330604
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  • 299
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    Kinetic model for the regulation of redox reaction in steroid transformation by Arthrobacter globiformis cells (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 668-680 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A kinetic model of hydrocortisone transformation was developed in studies of the kinetics of biochemical systems. The regulatory bases of the model are the biosynthesis of steroid-transforming enzymes and their activity, the level of endogenous substrates, the respiratory chain activity, and the initial concentrations of reagents. When compared, the experimental data completely coincide with the results of the computer modeling, the coincidence being not only qualitative but also quantitative. It indicates that the model suggested can be used for further studies of other transformations of steroid compounds, as well as for transformation of steroid compounds under close-to-biotechnological conditions. The results obtained by means of this model permit one to trace in dynamics the behavior of a number of parameters characterizing the process which is very difficult or not feasible to do in a biochemical experiment. The following was shown: (1) the behavior of the respiratory chain (the reversible transition of its oxidized and reduced forms); (2) the change of the transmembrane potential of hydrogen ions within a far larger stretch of time than is feasible to register in a biochemical experiment; (3) the regulation of the activity of 20β-hydroxysteroid dehydrogenase and 1, 2-reductase not only by the change in the level of endogenous substrates, but also by means of their biosynthesis; and (4) the regulatory role of 3-ketosteroid-1-en-dehydrogenase.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330603
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  • 300
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    An investigation of the efficacy of biological additives for the suppression of pyritic sulphur during simulated froth flotation of coal (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 694-698 
    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 biological molecule responsible for the suppression of pyritic sulfur in fine coal simulated froth flotation treated with bacteria was identified. Protein was found to be the most effective agent in pyrite suppression of the three cell components (protein, lipid, and carbohydrate) assayed. Coal recovery and ash removal of the flotation process were only slightly reduced by this treatment. Other protein-containing materials were evaluated for their ability to suppress pyrite flotation. Whey was found to be the most cost-effective flotation additive of those assayed. The sulfur content of the whey-treated float was reduced by 84.0% in a synthetically prepared fractionated coal (10.7% sulfur), by a raw whey dosage of 20 μL/g coal. The inorganic sulfur component of a natural high sulfur coal fraction (10.9%) was completely depressed by this whey addition. The effect of particle size and pulp density upon the process were investigated.
    Additional Material: 11 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260330606
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