| dc.description.abstract | Bioethanol production by batch fermentation using free cells has low productivity and efficiency. Furthermore, bioethanol production based on cassava starch produces bagasse as by-product which has not been utilized optimally. In this research, Saccharomyces cerevisiae was immobilized on cassava bagasse. This research aim to study bioethanol production from cassava starch in repeated-batch fermentation by Saccharomyces cerevisiae immobilized on iii cassava bagasse. Research method consists of starch extraction, starch hydrolysis, cassava bagasse treatment by HCl 3% (v/v), immobilization of Saccharomyces cerevisiae on cassava bagasse, and fermentation by repeated-batch method. The resulting yield of starch was 26.20% (w/w) and conversion efficiency of starch to hydrolyzed starch was 36.89% (w/w). The use of cassava bagasse treated by HCl 3% (v/v) is capable to immobilize 1.76x1011 cells/g carrier. The resulting ethanol concentration was 42.72-63.66 g/L, productivity 1.78-2.66 g/L/h, sugar conversion 90.80-95.74%, yield 0.33-0.47 g/g, and efficiency 65.91-93.13%. This result showed that ethanol production with repeated-batch fermentation by Saccharomyces cerevisiae immobilized on cassava bagasse has good stability, high productivity, sugar conversion, and efficiency. | en |
