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. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Optimum pH is 4.0. Stable between pH 3.0 and 7.0. Optimum temperature is 45 degrees Celsius. Stable up to 50 degrees Celsius. Belongs to the glycosyl hydrolase 7 (cellulase C) family.