Chakrabarti, A.C. and Storey, K.B. 1989. Enhanced glucose production from cellulase using coimmobilized cellulase and beta-glucosidase. Appl. Biochem. Biotech. 22, 263-278.

Enhanced Glucose Production from Cellulose Using Coimmobilized Cellulase and beta-Glucosidase

AJOY C. CHAKRABARTI AND KENNETH B. STOREY


ABSTRACT
beta-Glucosidase was covalently immobilized alone and coimmobilized with cellulase using a hydrophilic polyurethane foam (Hypol FHP 2002). Immobilization improved the functional properties of the enzymes. When immobilized alone, the Km for cellobiose of beta-glucosidase was decreased by 33% and the pH optimum shifted to a slightly more basic value, compared to the free enzyme. Immobilized beta-glucosidase was extremely stable (95% of activity remained after 1000 h of continuous use). Coimmobilization of cellulase and beta-glucosidase produced a cellulose-hydrolyzing complex with a 2.5-fold greater rate of glucose production for soluble cellulose and a four-fold greater increase for insoluble cellulose, compared to immobilized cellulase alone. The immobilized enzymes showed a broader acceptance of various types of insoluble cellulose substrates than did the free enzymes and showed a long-term (at least 24 h) linear rate of glucose production from microcrystalline cellulose. The pH optimum for the coimmobilized enzymes was 6.0. This method for enzyme immobilization is fast, irreversible, and does not require harsh conditions. The enhanced glucose yields obtained indicate that this method may prove useful for commercial cellulose hydrolysis.