Multifunctional enzyme involved in the degradation of plant cell wall polysaccharides. Displays endoglucanase activity against carboxymethyl cellulose (CMC) and barley beta-glucan (PubMed:3066698, PubMed:1991028). Also catalyzes the deacetylation of acetylated birchwood xylan and glucomannan, with a preference for the latter, and of the synthetic substrate 4-nitrophenyl acetate (4-NPAc) (PubMed:19338387). Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Deacetylation of xylans and xylo-oligosaccharides. Esterase activity of the CE2 module is inhibited when this domain binds to cellohexaose or beta-glucan. kcat is 7032 min(-1) for the deacetylation of 4-nitrophenyl acetate. kcat is 12 min(-1) for the deacetylation of birchwood xylan. kcat is 1.1 min(-1) for the deacetylation of glucomannan. Glycan metabolism; cellulose degradation. Glycan degradation; xylan degradation. Contains an N-terminal module that displays cellulase activity (CtCel5C), a central type I dockerin module (Doc) that facilitates the integration of the enzyme into the cellulosome, and a C-terminal module, CtCE2, which displays dual activities: it catalyzes the deacetylation of plant polysaccharides and also potentiates the activity of its appended cellulase catalytic module through its non-catalytic cellulose binding function. In the N-terminal section; belongs to the glycosyl hydrolase 5 (cellulase A) family. In the C-terminal section; belongs to the carbohydrate esterase 2 (CE2) family.