Synergistic action of two different types of endo-cellulase components from Irpex lacteus (Polyporus tulipiferae) in the hydrolysis of some insoluble celluloses.

The substrate specificities of three endo-cellulase [EC 3.2.1.4] components, F-1, F-2, and S-1, obtained from the culture filtrate of Irpex lacteus (Polyporus tulipiferae), were investigated in detail. It was confirmed that the former is of a more random type, belonging to the carboxymethyl-cellulase (CMCcase) group, and the latter two are of a less random type, beloning to the Avicelase group. It was found that a mixture of CMCase and Avicelase shows a remarkable synergistic action in the degradation of cotton and Avicel and that CMCase lowers the degree of polymerization of both cotton and CM-cellulose faster than Avicelases, relative to the production of reducing sugar. Thus, it was assumed that cotton and similar cellulosic substrates were degraded mainly by the synergistic action of these cellulase components produced by this celluloytic fungus.