Glucose Uptake in Electrically Stimulated Cultures of Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae shows rapid fermentation of sugars to ethanol and carbon dioxide. It is widely known that glucose and other sugars exert a repressive effect on the synthesis of a variety of enzymes. On the other hand, glucose may also exert enhancement of enzyme synthesis. The former are mitochondrial enzymes or enzymes linked to cellular respiration and the second are enzymes linked to fermentative metabolism. The external environment and its changes strongly influence the physiological behavior of yeast. Tight control of the sugar concentration at low threshold values prevents fermentation while high sugar concentrations trigger the catabolite repression, with a decrease of the biomass yield. Of special interest to control metabolic fluxes and direct the production to the aimed application (e.g., biomass or ethanol) is the relationship between glucose uptake and cell cycle. Furthermore, mastering ways of stimulating a culture through exogenous variables is interesting in the development of biotechnological processes. The results obtained in different aeration conditions had evidenced that the applied electric potential increases sugar consumption and impacts the cell cycle through alterations in the fraction of cells in division and in the number of scars per cell.