Media Evaluation for Bioethanol Production from Cassava Hydrolysate : POTENTIAL UTILIZATION OF CASSAVA STARCH FOR BIOETHANOL PRODUCTION FROM LOW COST MEDIA USING Saccharomyces cerevisiae

Different fermentation media were evaluated for bioethanol production using Saccharomyces cerevisiae. Three different nitrogen sources, concentration of carbon source (cassava starch hydrolysate, CSH) and the pH were combined to generate nine different fermentation media which were run in shake flasks. Analysis of variance of the results from shake flask experiments showed that there was no significant difference (P > 0.05) in the maximum concentration of ethanol (Pt) produced from the nine media after 24 h fermentation. From the bioreactor studies using minimal medium containing only ammonium sulphate as nitrogen source, Pt of 55.28 g/L (Yps of 0.49 g g-1 and 96% Yetoh), Q of 1.00 g g-1 h-1, Qp of 1.94 g g-1 h-1, Qs of 4.98 g g-1 h-1 and Yxs of 0.11 ( of 0.11h- 1) were obtained. The possibility of substituting ammonium sulphate for yeast extract in fermentation medium for bioethanol production from cassava starch hydrolysate (CSH) was confirmed.