Production of Ethanol from Sugars Fermentation By Yeasts Using Bioreactor

Two yeast isolates of C.kefyr-T and C.kefyr-S, were isolated from crude whey, the optimum pH value was 5, and S.cerevisiae was significantly best in ethanol and Biomass production from all glucose concentrations compared to C.kefyr-T and C.kefyr-S which were significantly best ethanol and biomass production from all galactose concentrations comparing with S.cerevisiae. C.kefyr-T which was best in production compared to C.kefyr-S. Best ethanol production was 8.7% Ethanol from 10% sugar mixture, by mixed culture of (S. cerevisiae+ C.Kefyr-T), and best ethanol production was 4.6% from 8% synthetic lactose by mixed culture of (C.kefyr-T+C.kefyr-S). There is a significant decrease in ethanol and biomass production from all mixtures by using mixed culture of (C.kefyr-T+ C.kefyr-S+ S. cerevisiae) than using mixed culture of (C. kefyr + S. cerevisiae) and mixed culture of (C.kefyr-T + C.kefyr-S). Different period of times at (24, 36, 48, and 60) h of fermentation in bioreactor are presented. The initial sugar mixture concentration was 10% in all cases. The ethanol production during the 48 h gave a maximum value of 15.5 % by mixed culture of (C. kefyr + S. cerevisiae), but it remains at low levels within other periods, whereas the highest biomass 16% gained at the same bioreactor conditions.