Fermentation of starch to ethanol by a complementary mixture of an amylolytic yeast and Saccharomycescerevisiae

Abstract

Synergistic coculture of an amylolytic yeast (Saccharomycopsisfibuligera) and S.cerevisiae, a non-amylolytic yeast, fermented unhydrolyzed starch to ethanol with conversion efficiencies over 90% of the theoretical maximum. Fermentation was optimal between pH 5.0 to 6.0. Using a starch concentration of 10% (w/v) and a 5% (v/v) inoculum of S.fibuligera, increasing S.cerevisiae inoculum from 4% to 12% (w/v) resulted in 35-40% (w/v) increase in ethanol yields. Anaerobic or "limited aerobic" incubation almost doubled ethanol yields. © 1987 Kluwer Academic Publishers.