Biotechnology Letters, Vol.35, No.11, 1859-1864, 2013
Increasing ethanol titer and yield in a gpd1 Delta gpd2 Delta strain by simultaneous overexpression of GLT1 and STL1 in Saccharomyces cerevisiae
We have investigated whether simultaneous modification of cofactor metabolism and glycerol in a strain of Saccharomyces cerevisiae can eliminate glycerol synthesis during ethanol production. Two strains, S812 (gpd1 Delta gpd2 Delta PGK1p-GLT1) and LE17 (gpd1 Delta gpd2 Delta PGK1p-GLT1 PGKp-STL1) were generated that showed a 8 and 8.2 % increase in the ethanol yield, respectively, compared to the wild type KAM-2 strain. The ethanol titer was improved from 90.4 g/l for KAM-2 to 97.6 g/l for S812 and 97.8 g/l for LE17, respectively. These results provide a new insight into rationalization of metabolic engineering strategies for improvement of ethanol yield through elimination of glycerol production.
Keywords:Ethanol fermentation;GLT1;gpd1 Delta gpd2 Delta;Osmotic stress;Saccharomyces cerevisiae;STL1