Glycerol production by semicontinuous fed-batch fermentation with immobilized cells of Saccharomyces cerevisiae

Abstract

Semicontinuous fed-batch glycerol fermentations with Saccharomyces cerevisiae cells immobilized in sintered glass Raschig rings were carried out in fixed-bed loop reactors with a working volume of either 0.8 l or 8 l. The influence of biomass, temperature and CO2 gassing on the glycerol yield was examined. The highest glycerol yield of 85 g l−1 was achieved at 30° C and average CO2 gassing rate of 0.4 v/v m with a theoretical glycerol yield of 67%. Fed-batch fermentations with free cells indicated an inhibition mechanism of the glycerol produced, affecting the fermentation capacity of the yeast strain used.