Hydrolyzes carboxymethylcellulose. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Glycan metabolism; bacterial cellulose biosynthesis. The genes bscA, bcsB, bcsZ and bcsC are constitutively transcribed but cellulose synthesis occurs only when DgcC, a putative transmembrane protein regulated by CsgD, is expressed. Cellulose production is abolished in E.coli K12. Belongs to the glycosyl hydrolase 8 (cellulase D) family.