Low-temperature alcoholic fermentation by delignified cellulosic material supported cells of kefir yeast

A novel system for low-temperature alcoholic fermentation of glucose is des cribed. This system consists of kefir yeast immobilized on delignified cell ulosic materials. Batch fermentations were carried out at various pH values , and the effect of temperature on kinetic parameters, in the range of 5-30 degrees C, was examined. At pH 4.7 the shortest fermentation time was obta ined. The formation of volatiles indicates that the concentration of amyl a lcohols (total content of 2-methylbutanol-1 and 3-methylbutanol-1) is reduc ed as the temperature becomes lower. Propanol-1 and isobutyl alcohol format ion drops significantly below 15 degrees C. The percentage of ethyl acetate increases as the temperature is diminished. At 5 degrees C the content of total volatiles in the product was only 38% of the volatiles formed during fermentation at 30 degrees C.