Has endoglucanase activity on substrates containing beta-1,4 glycosidic bonds, like in carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC) and beta-glucan. Involved in the degradation of complex natural cellulosic substrates (By similarity). Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Belongs to the glycosyl hydrolase 7 (cellulase C) family.