Synergistic temperature and ethanol effect on Saccharomyces cerevisiae dynamic behaviour in ethanol bio-fuel production

The impact of ethanol and temperature on the dynamic behaviour of Saccharomyces cerevisiae in ethanol biofuel production was studied using an isothermal fed-batch process at five different temperatures. Fermentation parameters and kinetics were quantified. The best performances were found at 30 and 33°C around 120 g l-1 ethanol produced in 30 h with a slight benefit for growth at 30°C and for ethanol production at 33°C. Glycerol formation, enhanced with increasing temperatures, was coupled with growth for all fermentations; whereas, a decoupling phenomenon occurred at 36 and 39°C pointing out a possible role of glycerol in yeast thermal protection.