 Chitosan and chitin belong to a family of biopolymers composed of β(1–4)-linked N-acetyl-D-glucosamine and D-glucosamine subunits.Chitosan is formed by alkaline N-deacetylation of chitin, which is the second most abundant natural polymer after cellulose.Chitosan is a biodegradable polysaccharide that has been useful in many biomedical applications such as a chelating agent, drug carrier, membrane, and water treatment additive.