Abstract:
Bioethanol is categorized as an interesting biofuel due to its efficiency of renewable energy source, low production costs and environmentally friendly. The objective of this research is to produce ethanol from cassava using a separate hydrolysis and fermentation (SHF) process. Optimization on saccharification by Amylomyces rouxii TISTR 3182 Was studied. The result showed that 20 % (w/v) cassava concentration without pH adjusted and 107 spore/mL of A. rouxii TISTR 3182 Were optimum conditions in 4th date showed glucoamylase activity and reducing sugars representing 3.09 ± 0.59 unit/mL and 84.17 ± 1.89 g/L, respectively. Followed by optimization on ethanol fermentation using immobilized Saccharomyces cerevisiae TISTR 5088, the result revealed that 2% (w/v) calcium alginate with diameter larger more than 3.35 mm at 1st date showed the highest ethanol concentration, yield of ethanol and productivity representing 35.14 ± 13.99 g/L, 0.36 ± 0.18 g/g and 0.24 ± 0.11 g/L/h, respectively, whereas the fermentation efficiency was 65.44% of the theoretical value, which was statistically insignificant difference to that of the free cell. Moreover, the immobilized cell was damaged in 1st date. Scanning electron microscope (SEM) study confirmed that immobilized S. cerevisiae TISTR 5088 grew on bead surface leading to widen gel porous.