Hydrolysis of corncobs using a mixture of crude enzymes from Trichoderma reesei and Aspergillus niger for bioethanol production
Sri Winarsih, Devi Dwi Siskawardani
Abstract
Corn plant produce waste as corncobs about 30% that relatively high and has not been utilized maximally. Corncobs are potential raw material for producing bioethanol. It composed of 41% cellulose, 36% Hemicellulose, 16% lignin and 7% water content. The converting cellulose into simple sugars could be process chemically or enzymatically. This study aimed to analysethe usage of enzymes from cellulase-producing microorganisms, Trichoderma reesei and Aspergillus niger in the hydrolysis process of corncobs for producing bioethanol. The method consisted of corncobs pretreatment, production crude enzyme, corncobs hydrolysis, and glucose fermentation. A mixture of the two enzymes in a ratio of 2:1 which had exoglucanase activity of 0.96 IU mL−1, endoglucanase of 1.99 IU mL−1 and β-glucosidase activity of 0.14 IU mL−1. Substrate concentration influences glucose hydrolysate levels. The substrate concentration of 7.5% could produce glucose of 128.20 mg mL−1 and the optimal time for enzymatic hydrolysis of corncobs is 72 h, which produces ethanol of 6.4 g L−1.