This enzyme catalyzes the endohydrolysis of 1,4-beta-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. EGB is most active against barley beta-glucan, but showed significant activity against amorphous and crystalline cellulose. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Belongs to the glycosyl hydrolase 45 (cellulase K) family.