Shows highest activity on carboxymethyl cellulose (CMC). Shows weak activity on xylan, and no activity against avicel, laminarin and chitin. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Is salt tolerant and retains more than 50% residual activity up to 15% NaCl. Optimum pH is 4.5 with CMC as substrate. Optimum temperature is 50 degrees Celsius with CMC as substrate. Retains 50% of its activity at temperatures ranging from 30 to 60 degrees Celsius. Belongs to the glycosyl hydrolase 5 (cellulase A) family.