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  • 1
    Electronic Resource
    Electronic Resource
    Analysis of the respiro-fermentative growth of Saccharomyces cerevisiae on glucose in a fed-batch fermentation strategy for accurate parameter estimation (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 664-669 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Analysis of the respiro-fermentative growth of a strain of Saccharomyces cerevisiae, DSM 2155 on glucose, in a simulated 5-phase feeding strategy of fed-batch cultures executed on the Universal BIoprocess CONtrol (UBICON) system, was carried out. There was a good agreement between the estimated and the simulated values of specific growth rates. In this study, which was designed to span 0.20–0.23 h–1 growth rates before returning to lower growth rates, the critical dilution rate at which the switch between purely oxidative and respiro-fermentative growth takes place was not observed. The biomass yield, specific substrate uptake and O2 consumption rates as well as the consistency of the data using both carbon and available electron balances were examined. A high average value of true biomass energetic yield, ηmax=0.707, and a low value of maintenance coefficient, me=0.0114 h–1, were obtained indicating that the organism was in no danger from the ethanol produced as a high-density fermentation with a yeast concentration above 54 g l–1 was possible within a period of 24 h. The yeast produced also had good dough-leavening characteristics. Thus it is possible to operate a yeast plant without resorting to using respiratory quotient, which may be problematic, as the controlling parameter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167282
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Analysis of the respiro-fermentative growth of Saccharomyces cerevisiae on glucose in a fed-batch fermentation strategy for accurate parameter estimation (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 664-669 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Analysis of the respiro-fermentive growth of a strain of Saccharomyces cerevisiae, DSM 2155 on glucose, in a simulated 5-phase feeding strategy of fedbatch cultures executed on the Universal BIoprocess CONtrol (UBICON) system, was carried out. There was a good agreement between the estimated and the simulated values of specific growth rates. In this study, which was designed to span 0.20–0.23 h−1 growth rates before returning to lower growth rates, the critical dilution rate at which the switch between purely oxidative and respiro-fermentative growth takes was not observed. The biomass yield, specific substrate uptake and O2 consumption rates as well as the consistency of the data using both carbon and available electron balances were examined. A high average value of true biomass energetic yield, ηmax = 0.707, and a low value of maintenance coefficient, me = 0.0114 h−1, were obtained indicating that the organism was in no danger from the ethanol produced as a high-density fermentation with a yeast concentration above 54 g 1−1 was possible within a period of 24 h. The yeast produced also had good dough-leavening characteristics. Thus it is possible to operate a yeast plant without resorting to using respiratory quotient, which may be problematic, as the controlling parameter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167282
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Effects of substrate limitation on product distribution and H2/CO2 ratio in Klebsiella pneumoniae during anaerobic fermentation of Glycerol (1994)
    Springer
    Applied microbiology and biotechnology 42 (1994), S. 222-226 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Product formation during anaerobic degradation of glycerol by Klebsiella pneumoniae DSM 2026, under glycerol limitation and glycerol excess in continuous cultures, has been investigated. Major and minor products and by-products as well as gaseous products were measured. The results indicated a positive correlation between specific glycerol uptake and most product formation rates under glycerol limitation. The production of 1,3-propanediol, lactate, formate, acetate, succinate and the by-products of anaerobic glycerol degradation by K. pneumoniae, acetoin and 2,3-butanediol, was favoured by glycerol excess, while hydrogen generation and ethanol formation were best under glycerol limitation. It was also found that under glycerol limitation the rate of hydrogen evolution was generally higher than the CO2 production rate while under excess glycerol the reverse was true. Hence, on the basis of the ratio of the specific rates of evolution of H2 and CO2 (q H2/q CO2), it is possible to infer the existence of glycerol limitation. On the basis of the carbon and available electron balances, which are independent of metabolic pathways, the data are consistent. The NADH2 balance, which took into consideration the pathways of product formation, was also tested to check the validity of the assumed pathways and to check critically the consistency of the data. Good balances were also obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00902720
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of substrate limitation on product distribution and H2/CO2 ratio inKlebsiella pneumoniae during anaerobic fermentation of glycerol (1994)
    Springer
    Applied microbiology and biotechnology 42 (1994), S. 222-226 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Product formation during anaerobic degradation of glycerol byKlebsiella pneumoniae DSM 2026, under glycerol limitation and glycerol excess in continugius cultures, has been investigated. Major and minor products and by-products as well as gaseous products were measured. The results indicated a positive correlation between specific glycerol uptake and most product formation rates under glycerol limitation. The production of 1,3-propanediol, lactate, formate, acetate, succinate and the by-products of anaerobic glycerol degradation byK. pneumoniae, acetoin and 2,3-butanediol, was favoured by glycerol excess, while hydrogen generation and ethanol formation were best under glycerol limitation. It was also found that under glycerol limitation the rate of hydrogen evolution was generally higher than the CO2 production rate while under excess glycerol the reverse was true. Hence, on the basis of the ratio of the specific rates of evolution of H2 and CO2 (q H 2/q CO 2), it is possible to infer the existence of glycerol limitation. On the basis of the carbon and available electron balances, which are independent of metabolic pathways, the data are consistent. The NADH2 balance, which took into consideration the pathways of product formation, was also tested to check the validity of the assumed pathways and to check critically the consistency of the data. Good balances were also obtained.[
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00902720
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Modelling of the metabolism of Zymomonas mobilis growing on a defined medium (1989)
    Springer
    Bioprocess and biosystems engineering 4 (1989), S. 217-222 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A structured model of Zymomonas mobilis is presented using fermentation data of a defined aspartate medium. After some remarks on the structure of the metabolism the model is derived by considering sub-models, e.g. balance equations, and by identifying the unknown parameters separately for each sub-model. Some results are the elemental composition of Zymomonas mobilis, a description of the substrate uptake during substrate limitation and the growth inhibition during substrate saturation. The results are shown as simulations and are discussed in relation to the inhibitory effect of ethanol on the bacterial cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369175
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  • 6
    Electronic Resource
    Electronic Resource
    A robust fed-batch feeding strategy for optimal parameter estimation for baker’s yeast production (1994)
    Springer
    Bioprocess engineering 11 (1994), S. 135-144 
    Details
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Parameter identification of structured models is often a problem in biotechnology, because the poor data situation and the number of unknown parameters only allow for inaccurate estimates. But often only a subset of all kinetic parameters of the model are of interest for production purposes, e.g. for fed-batch cultivation. These parameters should be estimated with a given accuracy. In addition, the experiments for information acquisition with respect to these parameters should be as simple as possible and should consider some practical restrictions. In this contribution a fed-batch feeding strategy is proposed to allow for an accurate estimation of yield and of critical growth rate of baker’s yeast. The feeding also allows for economic and stereotyped use of staff and equipment and is therefore suitable for routine use in screening of strains and media. The overall pattern is similar to that one, usually used in production scale to minimize errors by limited model validity. After an initial phase for achieving a reproducible state three different growth rates are adjusted to cover the range of possible critical growth rates. From biomass and ethanol measurements yield and critical growth rate can be estimated with an accuracy of about 2.1%. The fermentation pattern ends up with a constant feeding rate to simulate a limited oxygen transfer rate and to allow for an uptake of residual sugar and ethanol before a dough test can be carried out. Beside experimental results simulations and sensitivity analyses are shown. List of symbols P ethanol concentration S substrate concentration S f substrate concentration in feed T fermentation time V fermenter volume X biomass concentration C measurement error covariance matrix F Fisher information matrix X state variables Y output variables X p state sensitivity functions with respect to parameters Y p output sensitivity functions e eigenvectors k vector of limitation and inhibition parameters n number of observations q in feeding stream q b stream for samples and ammonia feed r vector of specific turnover rates y vector of yields ρ specific weight λ eigenvalues μ specific growth rate μset exponent in exponential feeding σ standard deviation
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00518735
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  • 7
    Electronic Resource
    Electronic Resource
    A robust fed-batch feeding strategy for optimal parameter estimation for baker's yeast production (1994)
    Springer
    Bioprocess and biosystems engineering 11 (1994), S. 135-144 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Parameter identification of structured models is often a problem in biotechnology, because the poor data situation and the number of unknown parameters only allow for inaccurate estimates. But often only a subset of all kinetic parameters of the model are of interest for production purposes, e.g. for fed-batch cultivation. These parameters should be estimated with a given accuracy. In addition, the experiments for information acquisition with respect to these parameters should be as simple as possible and should consider some practical restrictions. In this contribution a fed-batch feeding strategy is proposed to allow for an accurate estimation of yield and of critical growth rate of baker's yeast. The feeding also allows for economic and stereotyped use of staff and equipment and is therefore suitable for routine use in screening of strains and media. The overall pattern is similar to that one, usually used in production scale to minimize errors by limited model validity. After an initial phase for achieving a reproducible state three different growth rates are adjusted to cover the range of possible critical growth rates. From biomass and ethanol measurements yield and critical growth rate can be estimated with an accuracy of about 2.1%. The fermentation pattern ends up with a constant feeding rate to simulate a limited oxygen transfer rate and to allow for an uptake of residual sugar and ethanol before a dough test can be carried out. Beside experimental results simulations and sensitivity analyses are shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00518735
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Use of respiratory quotient as a control parameter for optimum oxygen supply and scale-up of 2,3-butanediol production under microaerobic conditions (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 1107-1114 
    Details
    ISSN: 0006-3592
    Keywords: 2,3-butanediol ; microaerobic culture ; RQ control ; oxygen supply ; reactor comparison ; scale-up ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The respiratory quotient (RQ) was found to be a suitable control parameter for optimum oxygen supply for the production of 2,3-butanediol + acetoin under microaerobic conditions. In laboratory scale continuous cultures optimum production of 2,3-butanediol + acetoin was obtained at an RQ value between 4.0 to 4.5. This agreed well with optimum RQ value (4.0) stoichiometrically derived from the bioreactions involved. In fed-batch cultures product concentrations as high as 102.9 g/L (96.0 g/L butanediol + 6.9 g/L acetoin) can be achieved within 32 h cultivation with an RQ control algorithm for oxygen supply. Under similar conditions only 85.7 g/L product (77.6 g/L butanediol + 8.1 g/L acetoin) was obtained with control of constant oxygen supply rate throughout the cultivation.In pilot scale batch cultures under identical oxygen supply rate the achievable RQ value was found to be strongly influenced by the reactor type and scale. The initial oxygen supply rate influenced the achievable RQ as well. However, in all the reactors studied the specific product formation rate of cells in the exponential growth phase was only a function of RQ. The same optimum RQ value as found in continuous cultures was obtained. It was thus concluded that RQ can be used as a control parameter for optimum production of 2,3-butanediol + acetoin in both laboratory and pilot plant scale reactors. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260440912
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  • 9
    Electronic Resource
    Electronic Resource
    161. Inhibierungsparameter für quasi-stationäre Bedingungen am Beispiel des Phenolabbaus durch Pseudomonas cepacia G4 (1996)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 68 (1996), S. 1169-1169 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.3306809163
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  • 10
    Electronic Resource
    Electronic Resource
    Scale-up von Bioreaktoren - Modellbildung und Kultivierung der Hefe Trichosporon cutaneum (1992)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 64 (1992), S. 870-870 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.3306409150
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    Paper (German National Licenses)
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