Influence of External Ethanol Additions on Fructose and Glucose Fermentations by Saccharomyces cerevisiae

Abstract:

To provide basic information for high gravity sugarcane fermentation, external ethanol was added to evaluate its impact on fructose and glucose fermentations by S.cerevisiae GJ2008. YPDF medium was used to simulate sugarcane juice to carry out ethanol fermentation at four different external ethanol concentrations ranging from 0% to 12% with an initial yeast number of 1.12×108 cells/mL, and the contents of fructose and glucose were determined by HPLC(High Performance Liquid Chromatography). Area under the curve (AUC) of fermentation of fructose and glucose was obtained using GraphPad Prism 5 software to analyze the discrepancy in fructose and glucose consumption. External ethanol addition had an important impact on fructose and glucose consumption, S.cerevisiae GJ2008 could utilize both sugars rapidly at the external ethanol concentration of less than 9% but with an obvious preference for glucose. Consumption of both sugars was severely inhibited when the external ethanol concentration increased up to about 12%, and the biomass could not be effectively produced. Fructose utilization was inhibited to a larger extent than glucose by external ethanol addition. The ethanol production was reduced by 19%~27% after the addition of external ethanol higher than 6%.