Cellulase, the enzyme that digests cellulose, is not produced in the mammalian digestive system. However, a type of mitotic bacteria lives in the digestive system of cows, buffaloes, goats, deer, sheep etc. All these bacteria produce cellulose digesting enzyme cellulase. This enzyme aids in cellulose digestion by cleaving the β, 1-4 glycosidic bonds of cellulose. Humans cannot digest cellulose because the human digestive system lacks such mitotic bacteria. But the human diet must contain cellulose-type food. Because cellulose is essential for the production of stool. Dr. Siddiq Publications