This enzyme catalyzes the endohydrolysis of 1,4-beta-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Principally active against barley beta-glucan. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Glycan metabolism; cellulose degradation. Belongs to the glycosyl hydrolase 9 (cellulase E) family.