The enhancement of the cellulolytic activity of cellobiohydrolase I and endoglucanase by the addition of cellulose binding domains derived from Trichoderma reesei

The effect of isolated cellulose binding domains (CBDs) on the hydrolysis of filter paper and microcrystalline cellulose by both cellobiohydrolase I and endoglucanase, was studied. CBDs were obtained by proteolysis from cellulases using a scaled-up variant of our previous method. Experiments were performed for different enzyme/substrate ratios in both the absence and presence of CBDs. Hydrolysis of filter paper by intact cellobiohydrolase I in the presence of additional CBDs was found to have a synergistic effect, leading to an increase of the sugar production of up to 30%. The effect was less pronounced using microcrystalline cellulose, where an increase up to 16% was observed. Similar trends were found during the hydrolysis of both substrates by endoglucanase.