The effect of medium composition and ethanol toxicity on the growth of Saccharomyces cerevisiae strain W303-1A(a).

Abstract

The growth of Saccharomyces cerevisiae strain W303-1A(a) was evaluated in complex and chemically defined media. The use of chemically defined medium allowed the complete utilisation of glucose within 20 h. as well as all of the produced ethanol within 45 h. Maximum specific growth rates (µmax) were increased from 0.28 h-1 to 0.42 h-1 and the volumetric rate of ethanol production increased from 0.204 g l-1 h-1 to 0.597 g l-1 h-1. However, when the ethanol concentration exceeded a threshold value of 10 g l-1, the µmax value was significantly decreased. These observations suggest that ethanol metabolism related growth experiments for the relevant strain should be carried out in chemically defined medium with ethanol concentrations below 10 g l-1.