Optimized mixtures of recombinant Humicola insolens cellulases for the biodegradation of crystalline cellulose.

The digestion of bacterial cellulose ribbons by ternary mixtures of enzymes consisting of recombinant cellulases (two cellobiohydrolases, Cel6A and Cel7A, and the endoglucanase Cel45A) from Humicola insolens was investigated over a wide range of mixture composition. The extent of digestion was followed by soluble sugar release (saccharification) analysis together with transmission electron microscopy (TEM) observations. It was found that the addition of minute quantities of Cel45A induced a spectacular increase in saccharification of the substrate with either Cel7A or the mixture of Cel6A and Cel7A.