Cotton fabrics modified by carboxymethylation to the degree of substitution (DS) of 0.02∼0.16 were separated into the salt-type CM-Cotton-Na with more water swelling and the acid-type CM-Cotton-H with less water swelling. The two types of cotton fabrics were treated with a commercially available cellulase product. For CM-Cotton-Na and CM-Cotton-H, the weight loss and the saccharification activities of the cellulase decreased with DS of 0.10 or less. The modification by carboxymethylation for cotton fabrics inhibited apparently the catalytic reaction of the cellulase. For CM-Cotton-Na and CM-Cotton-H, the cellulase showed the minimum value of the weight loss activity at DS of 0.10 and that of the saccharification activity at DS of 0.14. For CM-Cotton-Na, the cellulase exhibited larger value of the weight loss activity and smaller value of the saccharification activity at DS of 0.16 compared to the unmodified cotton fabric. We discussed that the endo-type cellulase attacked positively to CM-Cotton-Na with DS of 0.10 or more because of its more water swelling, but attacked negatively to CM-Cotton-H because of its less water swelling. On the other hand, the exo-type cellulase was inhibited to attack the modified cotton fabrics with DS of 0.10 or more.
