Enzymatic deacetylation of chitin treated with ionic liquids

Despite its unique properties (biocompatibility and nontoxicity), chitin itself has limited application. Chitin is completely insoluble in most organic or inorganic solvents which can be beneficial when chitin is investigated as a support for chromatography or enzyme immobilization. These applications require the particles to have an extensive outer surface with a large number of reactive ligands. The increase in specific surface area of chitin particles can be performed by dissolution in ionic liquid and precipitation with water. To increase the number of reactive ligands (amine groups), deacetylation of the surface of chitin particles is necessary. The deacetylation process can be carried out by an enzymatic process with the enzyme, chitin deacetylase. In our investigation, 21 ionic liquids were used for chitin particle structure modification followed by enzymatic deacetylation. Results proved the positive effect of modifications with ionic liquid on enzymatic deacetylation of the chitin surface with chitin deacetylase. For 12 samples the deacetylation increased the number of active ligands in comparison to natural chitin. The best results were observed for [Bmim][Br], [Emim][Cl] and [MPpip][Ac]. That could be correlated with an increase in outer surface area by increasing porosity of particles or by structural changes in chitin particles.