What is chitosan?

Chitosan is the name given to the polymers that are obtained by the deacetylation of chitin (poly-β-1,4-D-N-acetylglucosamine). At an industrial-scale, chitin is produced by treating seafood waste, especially shells from crustaceans (shrimps, crabs, lobsters, krills, etc).

The most popular technique for obtaining chitosan from chitin is alkaline deacetylation: this involves boiling chitin in concentrated alkali (50% w/v) for several hours. This will yield chitosan with a degree of acetylation between 20-30%: the most popular commercially available form of chitosan.

Special chemical treatments are needed to obtain completely de-acetylated forms of chitosan.

Chitin and chitosan chemistry have been extensively reviewed in the book written by Roberts (1), Chitin Chemistry.

Chitin and chitosan also exhibit various biological properties with wide potential applications. They are discussed in detail in Chitine et chitosane: Du polymère à l’application (80).

La chitine et le chitosane possèdent un large éventail de propriétés biologiques desquelles découlent nombreuses applications. Ces applications sont traitées en détail dans la monographie intitulée Chitine et chitosane: Du polymère à l’application (80).

Schematic representation of chitin and various chitosans:

Symbols: GlcNAc (N-acetyl-β-D-glucosamine)
GlcN (β-D-glucosamine)


Chitosan, partly acetylated (obtained by chemical methods):

Chitosan, partly acetylated (isolated from fungal cell wall) (2):

Chitosan, completely de-acetylated (obtained by chemical methods):

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This page was created by Ryszard Brzezinski, Marie-Ève Lacombe-Harvey and Andrzej Neugebauer.
Questions? Proposals? Comments? Write to Ryszard.Brzezinski@USherbrooke.ca
Last updated: 2013/07