Kinetic modeling of the enzymatic hydrolysis of pretreated cellulose.

The production of sugars by the enzymatic hydrolysis of cellulose is a two-step process that includes conversion of the intermediate cellobiose to glucose by beta-glucosidase. The hydrolysis was followed by analyzing the two sugar products (cellobiose and glucose). The enzyme showed maximum activity at pH 4.8. Thermal deactivation was significant at temperatures above 45 degrees C. At 50 degrees C (optimum temperature) thermal deactivation was found to follow first-order kinetics. Several models were tested by modeling the kinetics of the reaction. Their parameter values were determined by numerical optimization, including temperature dependence. The best fitting model was a competitive product inhibition for the two reactions in the operational range.