Two percent glucose complete synthetic medium was used in batch fermentations to study the effects of oxygen on the physiology of Saccharomyces cerevisiae under 1 vvm, 0.3 vvm, and unaerated dissolved oxygen tension with the same seed culturepreparation. It was found that the amounts of biomass generation, glucose uptake, and ethanol production were significantly different between the aerated and unaerated fermentations.There was no obvious difference in cell viability among these three experimental groups. However,the relative carbon flow to ethanol production,cell mass and cell maintenance were determined to be significantly different among these three different aeration rates. This indicates that the activity of pyruvate dehydrogenase and pyruvate decarboxylase were regulated by the different dissolved oxygen tensions during the fermentation process.
