Active on carboxymethyl cellulose and carboxymethyl cellulose-RBB but not avicel, xanthan gum, carboxymethyl-curdulan-RBB or carboxymethyl-xylan-RBB. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Strongly inhibited by ZnCl(2) and by EDTA. Optimum pH is 5-8. Optimum temperature is 60 degrees Celsius. Retains more than 90% activity after 24 hours at 50 degrees Celsius. Belongs to the glycosyl hydrolase 9 (cellulase E) family.