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.