Effect of some fermentation parameters on ethanol production from beet molasses by Saccharomyces cerevisiae CAIM13

Abstract

Problem statement: Some component of fermentation medium showed to reduce the Saccharomyces cerivisae production of ethanol. Approach: This study was designed to evaluate the role of some fermentation parameters in affecting ethanol productivity from beet molasses BM by Saccharomyces cerevisiae CAIM13. Results: Increase in cell concentration (inoculums size) of the yeast above 3.6×105 cells/100 mL decreased the ethanol yield. The yeast could tolerate ethanol concentration up to 10% but failed to grow at concentration of 12 and 15%. Employment of a benchscale tank fermenter enhanced the fermentation efficiency. 77% of BM sugars were assimilated after 48h giving a concentration of 5.4% ethanol. Utilization of a cell-recycling technique showed that the tested organism was capable of performing four fermentation cycles. The mud-free, H2SO4-treated beet molasses TBM was superior to sucrose in the repeated batch fermentation technique. A continuousflow fermentation technique employing immobilized yeast cells yielded maximum ethanol productivity after 6 days. Conclusion: The present investigation has demonstrated the importance of some fermentation parameters in improving the alcoholic fermentation technology of BM. When free cells of S. cerevisiae. In the case of immobilized cells, the continuous-flow technique speared superior to the repeated batch-fermentation technique in production of alcohol from TBM. © 2011 Science Publications.