Utilization of Agricultural Wastes as Energy Sources Enzymatic Hydrolysis of Cellulose to Glucose

Summary

The research project deals with the enzymatic hydrolysis of cellulose to glucose in ultrafiltration membrane reactors. The reaction is catalyzed by a multienzymatic complex (endoglucanases, exoglucanases and β-glucosidase). Most cellulase complexes are deficient in β-glucosidase; furthermore, the latter enzyme is somewhat labile as regards thermal stability. Therefore, a two step process has been studied in which cellobiose conversion to glucose by β-glucosidase is performed in a membrane reactor which could make use of a stabilized enzyme. In a first reactor cellulose is converted to soluble fractions by native cellulase complexes.

The optimal operating conditions for both reactors have been separately studied (in terms of thermal stability of the enzymes, optimal pH, effects of product inhibition and optimal reaction temperature). As far as the first reactor is concerned, the effect of several chemical and physical pretreatments on the rate of saccharification has been investigated. For the final reaction stage, the possible stabilization of β-glucosidase by soluble cellulose has been studied together with the effect of high molecular weight substrates accumulation at the membrane surface.