tailieunhanh - Báo cáo khoa học: Alcoholic fermentation with different initial glucose concentration using immobilized yeast in calcium alginate gel

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 | TẠP CHÍ PHÁT TRIỂN KH CN TẬP 11 SÓ 12 - 2008 ALCOHOLIC FERMENTATION WITH DIFFERENT INITIAL GLUCOSE CONCENTRATION USING IMMOBILIZED YEAST IN CALCIUM ALGINATE GEL Bui Thanh Huyen Le Van Viet Man University of Technology VNU-HCM Manuscript Received on March 27th 2006 Manuscript Revised Septemberl 03rd 2008 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 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. Ethanol has many uses in industry as well as in daily life. It is raw material in liquor production a popular solvent in many industries and gradually becomes a popular environment friendly fuel. The development of the ethanol industry led to the demand for effective fermentation technique to improve ethanol yield. Nowadays all Vietnamese ethanol factories carry out the alcoholic fermentation in medium with initial substrate concentration 150 g L. High gravity fermentation technology allows production of higher ethanol concentration without changing plant size. However in the culture with high initial substrate concentration yeast growth and metabolic activities were significantly inhibited due to the high osmotic .