Optimization of Culture Medium for Baker’s Yeast, Ethanol, Citric Acid and Α- amylase Production from Dates Syrup

The aim of this study is to optimize the production of Baker’s yeast, Citric acid, Ethanol and α-amylase using dates of low market value as the basal fermentation medium. The results of this study showed that the optimal Baker’s yeast production was obtained with a dilution rate of 0.22 h-1. Also, the use of ammonium phosphate provides better biomass yields compared to urea. As for the Ethanol production, the optimum yield obtained was 131.0 g/L under optimum conditions of an incubation period of 72 h, inoculums content of 4 % (w/v), sugars concentration of 180.0 g/L and ammonium phosphate concentration of 1.0 g/L. Concerning the Citric acid production, the cumulative effect of temperature (30 °C), methanol concentration (3%), initial pH (3.5) and ammonium nitrate concentration (2.5 g/L) during the fermentation process of dates syrup did increase the citric acid production to 97.0 g/L. Finally, the maximum α-amylase activity obtained was 2600 μmol/L/min under optimum conditions of an incubation period of 96 h, temperature of 30 °C, an initial pH of 5.5, sugars concentration of 20 g/L, yeast extract concentration of 5.0 g/L and phosphorus concentration of 5.0 g/L. Keys words: Dates/ Baker’s yeast / Ethanol/ Citric acid/ α-amylase