β-Glucosidase: microbial production and effect on enzymatic hydrolysis of cellulose

Abstract

The enzymatic conversion of cellulose is catalyzed by a multiple enzyme system. The Trichoderma enzyme system has been studied extensively and has insufficient beta-glucosidase (EC 3.2.1.21) activity for the practical saccharification of celluose. The black aspergilli (A. niger and A. phoenicis) were superior producers of beta-glucosidase and a method for production of this enzyme in liquid culture is presented. When Trichoderma cellulase preparations are supplemented with beta-glucosidase from Aspergillus during practical saccharifications, glucose is the predominant product and the rate of saccharification is significantly increased. The stimulatory effect of beta-glucosidase appears to be due to the removal of inhibitory levels of cellobiose.