Alcoholic fermentation with different initial glucose concentration using immobilized yeast in calcium alginate gel

Abstract

In this research, the growth and metabolic activities of Saccharomyces cerevisiae immobilized in alginate gel during alcoholic fermentation with different initial glucose concentration were studied. Starting from initial glucose concentration at 140 g/L, we observed that increasing this concentration to 220 g/L had little effect on the growth of immobilized yeast. Under the same conditions, the maximum biomass, glucose uptake rate, and final ethanol concentration obtained in the immobilized yeast cultures were always higher than those in the free yeast cultures. In 220 g glucose/L medium, the final ethanol concentration produced by immobilized yeast was very high (about 10.4-11.7% v/v). It can be concluded that immobilized yeast were less sensitive to high osmotic pressure and high ethanol concentration in medium than free yeast. Therefore, using immobilized yeast in alcoholic fermentation is potential to enhance ethanol productivity.