Chitin and chitosan dissolution

Chitin, together with cellulose and lignin, is one of the most abundant natural polymers. Chitin is a main component of the fungi cell walls, as well as exoskeletons of the insects and crustaceans, scales of fish etc. The monomer of chitin is N-acetylglucosamine, a derivative of glucose.  Chitosan is a relative of chitin, where most of the amino-groups are not acetylated. The structure of chitin and chitosan, like the one of cellulose, is interlinked with multitude of hydrogen bonds, and therefore it is not surprising that it is insoluble in traditional solvents. Similar to the case of cellulose, some ILs are able to efficiently disrupt hydrogen bonding and dissolve chitin. In particular, 1-alkyl-3-methylimidazolium halides, dimethylphosphates and acetates are prone to that.[1] In case of chitin, it is especially important to choose the right IL for its dissolution, as traditional use include pharmaceutical and food industry, as well as modification of paper and therefore toxic solvents should be avoided to minimize intermediate washing of reconstructed chitin. ILs solutions of chitin were also shown to be useful for making composite materials,[2] CO₂[3] fixation, and encapsulation of enzymes.[4]