Metabolic fluxes in chemostat cultures of Schizosaccharomyces pombe grown on mixtures of glucose and ethanol

Article Abstract:

Schizosaccharomyces pombe is incapable of complete utilization of ethanol even as a co-substrate. The absence of the glyoxylate cycle prevents the use of ethanol as the sole carbon source. The organism, however, co-consumes ethanol in glucose-limited chemostat cultures. An ethanol concentration of more than 30% of the substrate carbon in mixed feeds results in incomplete utilization of ethanol. In mixed-substrate cultures with saturating ethanol fractions the increase in biomass as a result of ethanol consumption is highest when the dilution rates are low.

Usage, Physiological aspects, Microbial growth, Culture media (Biology), Culture media, Alcohol, Ethanol

Coordination of sucrose uptake and respiration in the yeast Debaryomyces yamadae

Article Abstract:

The inability of the yeast Debaryomyces yamadae to ferment sucrose, the Kluyver effect, is due a decrease in the activity of sucrose carriers when the oxygen concentration is limited. The Kluyver effect is not due to the inhibition of the enzymes such as pyruvate decarboxylase and alcohol dehydrogenase involved in alcoholic fermentation. This yeast does not show a preference for ethanol when grown in the presence of ethanol and sucrose. However sucrose metabolism takes place by the intercellular hydrolysis, and the yeast is able to respire sucrose.

Inactivation of the Kluyveromyces lactis KlPDA1 gene leads to loss of pyruvate dehydrogenase activity, impairs growth on glucose and triggers aerobic alcoholic fermentation

Article Abstract:

Research was undertaken to develop a Kluyveromyces lactis null mutant lacking the pyruvate dehydrogenase (PDH) activity and compare its phenotype with an isogenic wild-type strain. K. lactis is often used as a model organism for molecular studies on the regulation of sugar metabolism and respiration. Results revealed that the development of an aerobic fermentation and the slow growth of the Klpda null mutant demonstrated that the enzymes of the PDH bypass were incapable of replacing the PDH complex during batch cultivation on glucose.

Genetic aspects, Dehydrogenases, Oxidoreductases