STUDIES ON THE MECHANISM OF ENZYMATIC-HYDROLYSIS OF CELLULOSIC SUBSTANCES

Most cellulosic substances contain appreciable amounts of cellulose and hemicellulose, which on enzymatic hydrolysis mainly yield a mixture of glucose, cellobiose and xylose. The mechanisms of hydrolysis of bagasse (a complex native cellulosic waste left after extraction of juice from cane sugar) by the cellulase enzyme components are described in light of their adsorption characteristics. Simultaneous adsorption of exo- and endoglucanases [Trichoderma reesei] on hydrolyzable cellulosics is the causative factor of the hydrolysis that follows immediately after. It supports the postulate of synergistic enzyme action proposed by Eriksson. Xylanase pretreatment enhanced the hydrolysis of bagasse owing to the creation of more accessible cellulosic regions that are readily acted upon by exo- and endoglucanases. The synergistic action of the purified exoglucanase, endoglucanase and xylanase [Aspergillus wentii] was most effective for hydrolysis of bagasse but not for pure cellulose. Significant quantities of glucose are produced in .beta.-glucosidase-free cellulase action on bagasse. Individual and combined action of the purified cellulase components on hydrolysis of native and delignified bagasse are discussed in respect to the release of sugars in the hydrolysate.