Hydrolyzes carboxymethylcellulose (CMC) (PubMed:24848382, PubMed:28156112). Hydrolyzes also lichenan and barley beta-1,4-D-glucan. CMC is hydrolyzed majorily to cellobiose (G2), cellotriose (G3) and cellotetraose (G4). Cellohexaose (G6) is hydrolyzed to G4 and G2 with traces of G3. Cellopentaose (G5) is completely hydrolyzed to G2 and G3, and G4 is partially hydrolyzed to G2. Does not hydrolyze G2 or G3. Does not hydrolyze crystalline cellulose, soluble starch, xylan, mannan or laminarin (PubMed:28156112). Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Activity is not affected by metal ions except Mn(2+), which reduces the activity by 40-50%. However, no significant change in activity in response to 1 mM EDTA. Optimum pH is 3.5 (PubMed:24848382, PubMed:28156112). More than 90% of the maximal activity is maintained between pH range 3-5 (PubMed:24848382). More than 60% of the maximal activity is maintained between pH range 2-8 (PubMed:24848382, PubMed:28156112). About 80% of the maximal activity is maintained even at pH 2.5 (PubMed:28156112). Optimum temperature is around 40-50 degrees Celsius (PubMed:24848382, PubMed:28156112). Has more than 50% of the maximal activity between 10-70 degrees Celsius, and more than 30% of activity at 0 degrees Celsius. Stable at 50 degrees Celsius for 30 min (PubMed:24848382). 60-80% of the maximal activity is retained between 0-10 degrees Celsius. Displays 40% of its maximal activity at as high as 80 degrees Celsius. Remains active at 60 degrees Celsius for over 8 hours. Approximately 50% of the activity is still maintained after 4-hour incubation at 70 degrees Celsius (PubMed:28156112). N- and O-glycosylated. Contains hybrid- and complex-type N-glycans. Potential use as a cellulase in industry due to its high catalytic activity at low temperature as well as its thermotolerance (PubMed:24848382). Digests green algae (Ulva pertusa) under acidic conditions at 50 degrees Celsius, which suggests that it could be used for biofuel production from seaweeds (PubMed:28156112). Belongs to the glycosyl hydrolase 45 (cellulase K) family.