Modes of Action of Exo- and Endo-Cellulases in the Degradation of Celluloses I and II

Abstract

Cotton and Valonia-celiulose (cellulose I) were readily attacked by endo-cellulase of a highly endowise-hydrolysis type, with a sharp decrease in the degree of polymerization, while the simultaneous production of reducing sugar was low. In contrast, viscose rayon and alkalicellulose (cellulose II) showed little lowering of the degree of polymerization by endo-cellulase, though the effect was slightly greater than with an exo-cellulase, while the simultaneous production of reducing sugar was very high. The synergistic effect of exo- and endo-cellulases on the hydrolysis of cellulose was much higher with cellulose I than with cellulose II. These results can be explained in terms of differences in the polarity of cellulose chains and in the crystallinity and/or ultrastructure of the cellulose fibers.