Action modes of recombinant endocellulase, EGA, and its domains on cotton fabrics.

The action modes of an endocellulase, EGA, and its domains (CD9 and CBM3) during enzymatic treatment of cotton fabrics were investigated. EGA, CD9 and CBM3 had the binding capacity to cellulose substrates, of which the filter paper was the substrate with the strongest binding capacity. Analyses of scanning electronic microscopy indicated that EGA and its catalytic domain CD9 etched the surface of cotton fabrics and broke the fibers of long chains. On the other hand, the binding domain CBM3 only resulted in swelling of cotton fibers. Both EGA and its catalytic domain CD9 had minimal effect on the weight loss of cotton fabrics, whereas the effect of EGA and CD9 on the degree of polymerization and breaking strength was significant. After 12 h enzymatic action, the values of weight loss ratio for EGA and CD9 were 2.07 and 2.21 %, respectively, meanwhile the reductions in fabric strength were 27.04 % for EGA and 17.23 % for CD9. In contrast to the action of EGA and CD9, CBM3 showed no significant changes in terms of the weight loss ratio, degree of polymerization, and fabric strength.