Cellulolytic Activities of Strains of the Genus Cellulomonas

Abstract

The effects of pH, temperature, the presence or absence of glucose and cellobiose, and culture medium on cellulase synthesis or activity or both by 12 strains of Cellulomonas were compared. The liquefaction of carboxymethyl cellulose (CMC) gels by eight of the strains was examined. The optimum temperature for hydrolysis of CMC during growth was 40°C, and the optimum pH was 7 to 7.5. The eight strains broke into two distinct groups with a fourfold difference in rates of CMC or filter paper hydrolysis during growth. The presence of either glucose or cellobiose in the culture medium stimulated growth but repressed either the synthesis or the activity of CMC and filter paper cellulases. This effect is the opposite of that reported previously for Bacillus CMC cellulase. The greatest rate of filter paper hydrolysis occurred in a synthetic medium. The cell-free carboxymethylcellulase of Cellulomonas flavigena ATCC 482Twas partially purified by molecular exclusion chromatography on Bio-Gel P-100 and Sephadex G-75. The partially purified enzyme had a molecular weight of 40,000 and optimum activity at pH 7.0. Cellobiose was a competitive inhibitor of the enzyme activity. The results obtained with the partially purified enzyme indicated that the results obtained by using CMC gels were valid.