Cellulose
Cellulose is the most common biopolymer, and it can be found in an extensive range of living organisms that employ it as a support material. It is a crucial constituent in the firm cell wall of plants. In 1838, the French chemist Anselme Payen first discovered cellulose when studying plant cell walls. Cellulose is made up of a 10,000 to 15,000 linear chain of glucose molecules joined by acetal oxygen covalent links between the C1 of one glucose ring with the C4 of the next ring, which is formed via β(1→4)-glycosidic bonds. In disparity to this linking pattern, α(1→4)-glycosidic linkages are in starch and glycogen. Cellulose is a straight-chain polymer. Several cellulose chains are connected by hydrogen bonds and form elementary fibrils, which aggregate into 5-50 nm diameter and several microns in length microfibrils. The microfibrils, in turn, are bundled together to form microfibrils. The microfibrils of cellulose are extremely tough and inflexible due to hydrogen bonds. Humans lack the enzymes (cellulase) to break down the beta acetal bonds. Therefore, cellulose cannot be digested by them. On the other hand, the intestine tract of animals such as termites, sheep, goats, cows, and horses have symbiotic bacteria that have the appropriate enzymes to break down or hydrolyze the cellulose and other enzymes needed to digest cellulose in the GI tract. Cellulose particles are known as 'green' substances. Cellulose is a polysaccharide (or carbohydrate) that poses minor damage to the environment, health, or safety. It has diverse use, including food additives (thickener, emulsion stabilizer, fiber), cellophane, artificial tears, chronic wound treatment (scaffolding structure for tissue engineering, artificial blood vessels, cartilage, etc.), and drug tablets filler material. [Mohammad Riazul Islam]