Optimizing of alcohol production from manioc starch

The objective of this study was the optimization of the manioc root starch hydrolysis by a-amylase from A. niger and alcohol production from this starch syrup. Hydrolysis assays were performed at pH 4.8, the starch concentration and the temperature varied from 7 to 22 g.L-1, and 30 to 59.1 degrees C, respectively. The starch contents during the syrup fermentation were 2.2 and 5%. The results of the starch hydrolysis showed that the hydrolysis time was between 20-200 minutes, the RSM analysis showed a decrease in the starch yield at the average concentration and above of 70% at high temperatures, and the optimal conditions were found at temperature between 55-59.1 degrees C and concentration between 7.9-10 or 20-22 g.L-1; conditions at which 80% of the starch was hydrolyzed. The best fermentation condition was obtained for the must containing 5% of starch. The final fermentation composition obtained was of 0.68 g.L-1 ART and 0.572 g.L-1 AR. After the fermentation process, an alcohol yield of 45% was obtained showing that this process is a very good alternative for sugar-alcohol industries.