Ethanol Production From Sweet Potato by Enzymatic Hydrolyzation and Saccharomyces Cerevisiae YRK 017 Fermentation

The aim of this work was to utilize sweet potato for production of bioethanol. Optimal conditions of a-amylase and glucoamylase was carried on hydrolyzation of sweet potato and measurement of reducing sugars. The optimal a-amylase concentration and volume were 0.05% (w/v) and 5 ml, respectively at 90°C for 2 h. Using these conditions, the maximum concentration of reducing sugar was 16.43 g L^-1. The optimum glucoamylase concentration and volume were 0.015 (w/v) and 20 ml, respectively at 60°C for 4 h. The concentration of reducing sugar was 41.78 g L^-1. After hydrolyzation of sweet potato with these two enzymes at optimal condition and fermented using Saccharomyces cerevisiaeYRK 017 (isolated from Loog-pang), the maximum ethanol concentration of 14.55 g L^-1 was achieved after 72 h of separate hydrolysis and fermentation process (SHF). For simultaneous saccharification and fermentation process (SSF), the maximum concentration of ethanol was 12.62 g L^-1

Keywords: Sweet potato, Saccharomyces cerevisiae, Bioethanol, Simultaneous saccharification and fermentation

^*Corresponding author: E-mail: kodaungj@kmitl.ac.th