Chitin and its deacetylated derivative chitosan are natural polymers composed of randomly distributed beta-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). Chitin is insoluble in aqueous media while chitosan is soluble in acidic conditions due to the free protonable amino groups present in the D-glucosamine units. They both are highly valuable, and used in different fields of food, biomedicine and agriculture and so on. The success of chitin and chitosan in each of these specific applications is directly related to deep research into their...