ISSN:
1432-072X
Schlagwort(e):
Candida utilis
;
Saccharomyces cerevisiae
;
Glucose
;
Formate
;
Mixed-substrate utilization
;
Growth yield
;
Transhydrogenase
;
Continuous culture
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Candida utilis CBS 621 andSaccharomyces cerevisiae CBS 8066 were grown in glucose-limited chemostat cultures with formate as an additional energy source. In both yeasts formate was oxidized via a cytoplasmic NAD+-linked formate dehydrogenase. Other formate-oxidizing enzymes could not be detected. WithCandida utilis the steady-state cell yield on glucose increased with increasing amounts of formate in the medium until growth became carbon-limited. The maximum growth yield on glucose in the presence of excess formate was dependent on the nitrogen source used for growth. With ammonium and nitrate the maximum yields were 0.69 and 0.56 g cells/g glucose, respectively. Calculations showed that this difference correlates with the NADPH requirement for biomass formation with these two nitrogen sources. This implies that the NADH produced from formate oxidation cannot replace the NADPH needed for biomass formation. It therefore is concluded that inCandida utilis transhydrogenase activity is absent. AlsoSaccharomyces cerevisiae was capable of oxidizing formate in glucose-limited chemostat cultures. However, in contrast toCandida utilis utilization of formate by this yeast did not enhance the cell yield on glucose.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00693408
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