PREPARATION OF LOW-VISCOSITY CARBOXYMETHYLCELLULOSE BY USING ENZYME

摘要

PROBLEM TO BE SOLVED: To realize the viscosity reduction of an aqueous solution of carboxymethylcellulose even of high concentration by dissolving or dispersing an enzyme in water to prepare a solution beforehand and slowly adding raw material carboxymethylcellulose thereto. SOLUTION: An aqueous solution is prepared by dissolving an enzyme comprising cellulase and its mixture in an amount of 0.02-1.0 wt.% based on a carboxymethylcellulose having a degree of substitution of carboxymethyl groups of 0.3-2.0 in water having a pH kept at 3.5 to 6.0 by adding a buffer solution. The carboxymethylcellulose in an amount sufficient to provide a solid concentration of 20-60 wt.% is slowly added to the aqueous solution of enzyme heated to 30-50 deg.C to effect hydrolysis while keeping the viscosity of the reaction solution at 10,000 mPa.s or lower. After completion of the reaction, the reaction solution is spray dried at 80-180 deg.C to deactivate the enzyme, thus giving a carboxymethylcellulose powder free from residual enzyme. The buffer solution used comprises e.g. an acetate, a phosphate or citrate.