Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Occurrence of cytochrome P450 in continuous cultures of Saccharomyces cerevisiae (1982)
    Springer
    Applied microbiology and biotechnology 15 (1982), S. 64-68 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Cytochrome P450 of Saccharomyces cerevisiae is an inducible enzyme system. Hitherto, its induction was related to semi-anaerobic culture conditions and high glucose concentrations in the growth medium respectively. Since glucose and oxygen are main regulatory effectors in this yeast, the relationship between the occurrence of cytochrome P450 and these two effectors was established in continuous culture. At glucose-derepressed conditions it was not possible to induce the formation of cytochrome P450 by oxygen limitation alone. The oxygen supply had to be decreased to a level where glucose repression also became active. At glucose-repressed conditions cytochrome P450 was obtained in good yield (3 to 5 pmol per mg dry cell weight) below a dissolved oxygen tension of appproximately 15%. There was a correlation between the content of mitochondrial cytochromes and that of cytochrome P450. The presence of mitochondrial cytochromes was reciprocal with cytochrome P450 when its content was increased by lowering the dissolved oxygen tension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00499508
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Chemostat studies on the assimilation of hexadecane by the yeastCandida tropicalis (1981)
    Springer
    Applied microbiology and biotechnology 12 (1981), S. 129-134 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The yeastCandida tropicalis was grown in a chemostat with hexadecane as the sole carbon source. The influence of the dilution rate, oxygen and ammonium limitation on s, x, Ys, QO 2, QCO 2, and Qs was investigated. When the extracellular hexadecane concentration exceeded 120 mg l−1 (at dilution rates close to Dc, at pO2 below 2.54 kPa and at ammonium limited growth) Ys decreased and QO 2, QCO 2, and Qs increased. It was concluded that uncoupling of the mitochondrial respiratory chain occurred under these conditions. The QO 2 was determined by two different methods: first in situ, with a gasanalyzer directly connected to the bioreactor to analyze the outcoming gas, and second, with a sample from the bioreactor transferred to a Clark-type oxygen electrode. When cell growth was not oxygen limited in the chemostat (pO2 above 2.54 kPa), no apparent difference between the in situ and the dynamically determined QO 2 was observed. In contrast, when cell growth was oxygen limited in the chemostat, the QO 2 measured in the Clark-type oxygen electrode was remarkably higher than the in situ QO 2. This indicates that the electron transport chains are limited bythe oxidases, when the cells lack oxygen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01008332
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Chemostat studies on the hexadecane assimilation by the yeastCandida tropicalis (1981)
    Springer
    Applied microbiology and biotechnology 12 (1981), S. 135-142 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The yeastCandida tropicalis was grown on glucose or hexadecane in batch cultures and on hexadecane in chemostat cultures. The cytochrome content and activities of several enzymes were determined in harvested cells. Cytochrome P-450 was induced and long chain alcohol and aldehyde hydrogenase were derepressed when hexadecane was the sole carbon source instead of glucose. Therefore, these enzymes are functionally related to hexadecane oxidation. A remarkable relationship was observed between the relative content of cytochrome P-450 and Qs in the chemostat and this relationship was more obvious when the cells grew in conditions of oxygen limitation. Alcohol and aldehyde dehydrogenase showed no regulation and therefore the primary hydroxylation of hexadecane by cytochrome P-450 is presumed to be the rate limiting step in hexadecane uptake and subsequent oxidation to palmitate. The specific activity of cytochromec oxidase was also remarkably higher when the cells were grown under conditions of oxygen limitation. Limitation of the electron transport chains by the oxidases, in conditions of oxygenlimitation, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01008333
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Mixed substrate growth of methylotrophic yeasts in chemostat culture: Influence of the dilution rate on the utilisation of a mixture of glucose and methanol (1982)
    Springer
    Archives of microbiology 131 (1982), S. 8-13 
    Details
    ISSN: 1432-072X
    Keywords: Hansenula polymorpha ; Kloeckera sp. 2201 ; Mixed substrate utilisation ; Chemostat ; Induction ; Repression ; Methanol ; Glucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of Hansenula polymorpha and Kloeckera sp. 2201 with a mixture of glucose and methanol (38.8%/61.2%, w/w) and the regulation of the methanol dissimilating enzymes alcohol oxidase, catalase, formaldehyde dehydrogenase and formate dehydrogenase were studied in chemostat culture, as a function of the dilution rate. Both organisms utilized and assimilated glucose and methanol simultaneously up to dilution rates of 0.30 h-1 (H. polymorpha) and 0.26h-1, respectively (Kloeckera sp. 2201) which significantly exceeded μmax found for the two yeasts with methanol as the only source of carbon. At higher dilution rates methanol utilisation ceased and only glucose was assimilated. Over the whole range of mixed-substrate growth both carbon sources were assimilated with the same efficiency as during growth with glucose or methanol alone. In cultures of H. polymorpha, however, the growth yield for glucose was lowered by the unmetabolized methanol at high dilution rates. During growth on both carbon sources the repression of the synthesis of all catabolic methanol enzymes which is normally caused by glucose was overcome by the inductive effect of the simultaneously fed methanol. In both organisms the synthesis of alcohol oxidase was found to be regulated differently as compared to catalase, formaldehyde and formate dehydrogenase. Whereas increasing repression of the synthesis of alcohol oxidase was found with increasing dilution rates as indicated by gradually decreasing specific activities of this enzyme in cell-free extracts, the specific activities of this enzyme in cell-free extracts, the specific activities of catalase and the dehydrogenases increased with increasing growth rates until repression started. The results indicate similar patterns of the regulation of the synthesis of methanol dissimilating enzymes in different methylotrophic yeasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00451491
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Regulatory flexibility of methylotrophic yeasts in chemostat cultures: Simultaneous assimilation of glucose and methanol at a fixed dilution rate (1982)
    Springer
    Archives of microbiology 131 (1982), S. 1-7 
    Details
    ISSN: 1432-072X
    Keywords: Hansenula polymorpha ; Kloeckera sp. 2201 ; Chemostat ; Mixed substrates ; Glucose ; Methanol ; Growth yields ; Enzyme regulation ; Dissimilatory enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of the composition of methanol/glucose-mixtures as only sources of carbon and energy on growth and regulation of the synthesis of enzymes involved in methanol-dissimilation was studied under chemostat conditions at a fixed dilution rate with the methylotrophic yeasts Hansenula polymorpha and Kloeckera sp. 2201. Both carbon sources were found to be utilized completely independently of the composition of the C1/C6 mixture. Using mixtures of 14C-labelled methanol and glucose the growth yield for glucose was found to be constant for all C1/C6-mixtures tested and both yeasts. The growth yield for methanol, however, was reduced by up to 25% when the proportion of methanol in the inflowing medium was lower than 20% (w/w with respect to glucose) for H. polymorpha and 50% (w/w with respect to glucose) for Kloeckera sp. 2201 respectively. During growth with C1/C6-mixtures containing higher C1-proportions of methanol regular growth yields for methanol were recorded which corresponded to the growth yields found with methanol as the only carbon source. The regulation of the synthesis of the enzymes of the dissimilatory pathway for methanol was found to be under multiple control. Although glucose was present in the medium methanol had a positive effect on the synthesis of these enzymes. Thus, in addition to derepression induction by methanol was also observed. This inductive effect was found to increase with increasing proportions of methanol in the mixture. Depending on the enzyme, 10–40% methanol in the mixture resulted in a maximal induction with enzyme specific activities equal to those found in cells grown with methanol as the only carbon source. No further enhancements in enzyme specific activities were observed during growth on mixtures containing more than 40% methanol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00451490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    On the methodology of oxygen transfer coefficient measurments (1981)
    Springer
    Biotechnology letters 3 (1981), S. 541-546 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A method for the determination of the kLa in microbial cultures is described. It is based on the relation that expresses the kLa in function of the oxygen transfer rate and the oxygen driving force. Its application is demonstrated by showing the influence of the stirring geometry and intensity as well as the aeration rate and the salts concentration on the kLa of a bioreactor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00133430
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Characteristics of hexadecane partition by the growth medium of Acinetobacter sp. (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 495-503 
    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 partition of n-hexadecane in the spent growth medium of Acinetobacter sp. HOI-N was determined by measuring the increase in the relative aqueous solubility of 3H-hexadecane as compared to controls. The amount of hexadecane partitioned was proportional to the protein concentration. The specific solubility of hexadecane (nmol/mg protein) was analyzed by least-squares fitting yielding an average slope of 0.6 with a standard deviation of 0.3, indicating either nonequilibrium of hexadecane or physical aggregation of protein. The amount of hexadecane partitioned was concentration dependent yielding optically clear microemulsions at hexadecane concentrations of less than 1.4mM and macroemulsions at hexadecane concentrations of 1.4mM or greater. Preliminary results indicated that hexadecane and partitioned by a lipoprotein complex.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A convenient method for the determination of oxygen solubility in different solution (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 23 (1981), S. 1897-1901 
    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.260230817
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Partition of hexadecane to the cell surface of Candida tropicalis: Mechanism for the transport of water-insoluble substrates (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 1829-1841 
    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 partition of hexadecane to the cell surface of Candida tropicalis was measured by incubating heat-inactivated cells with hexadecane-1-14C on a gyratory shaker. The free hexadecane was separated by centrifuging the cells through a 15% sucrose solution, and the partitioned hexadecane was quantified by scintillation spectrometry of the samples from the resulting cell sediment. Heat-inactivated cells did not take up hexadecane as determined by a membrane filtration technique involving organic solvent washing. The partitioning was a time-dependent process. The velocity increased by increasing the shake rate of te shaker. At 360 rpm and with baffled flasks, saturation of the cell surface with hexadecane was obtained after a 20 min incubation period. The amount of hexadecane partitioned depended on the initial hexadecane-to-cell concentration ratio. At a ratio of 5 μmol/mg cell protein the highest amount of hexadecane partitioned was measured at 2100 μmol/mg cell protein. At ratios higher than 6 μmol/mg cell protein the cells were no longer sedimentable by centrifugation. The partition of hexadecane to the cell surface was affected by removing the surface layer of the cell wall by Pronase treatment and by using detergents in the partition assay. Pronase treatment lowered the amount of hexadecane partitioned as a consequence of the removal of the lipophilic layer of the cell surface. Detergents influence the partition coefficient and also lowered the amount of hexadecane partitioning to the cell surface. At a low shaking intensity (280 rpm, unbaffled flasks), after Pronase treatment, and in the presence of detergents he uptake of hexadecane by the cells was limited by the partitioning.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260220905
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Growth of Trichosporon cutaneum under oxygen limitation: Kinetics of oxygen uptake (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 24 (1982), S. 2519-2526 
    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 relationship between oxygen concentration and growth rate in the yeast Trichosporon cutaneum was studied. In order to establish the conditions for purely oxygen-limited growth, the cells were first grown in a carbon-limited chemostat, and kinetic parameters determined. The cells were then grown in an oxygen-limited chemostat at different dilution rates yielding different oxygen uptake rates. The steady-state dissolved oxygen tension was found at each dilution rate and the corresponding equilibrium dissolved oxygen tension was found at each dilution rate and the corresponding equilibrium dissolved oxygen concentration determined in the effluent medium. The relationship between oxygen concentration and growth rate followed Monod-type kinetics with an apparent KO of 4.38 × 10-6M.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260241115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...