Produksi Bioetanol dari Hidrolisat Pati Singkong Racun dengan Fermentasi Repeated-Batch oleh Saccharomyces cerevisiae Terimobilisasi pada Ampas Singkong

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.