Chitosan is a natural polysaccharide comprising of
copolymers of glucosamine and N-acetylglucosamine, and can be obtained by the partial deacetylation of chitin. In
its crystalline form, chitosan is normally insoluble in aqueous solutions above pH7; however, in dilute acids (pH6.0),
the protonated free amino groups on glucosamine facilitate solubility of the molecule. Chitosan
can be obtained by deacetylation of chitin through enzymatic or alkaline method during the course of deacetylation;
parts of polymer N-acetyl links are broken with the formation of D-glucosamine units, which contain a free amine
group, increasing the polymer’s solubility in aqueous means.