Has endoglucanase activity on carboxymethyl-cellulose (CMC), xylan and lichenan, but not Avicel. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Up to 32 AA of the N-terminus and 52 AA of the C-terminus are not required for catalytic activity. Belongs to the glycosyl hydrolase 5 (cellulase A) family.