## 4 Chitosan as Catalytic Support
### Chitosan-Containing Composite Biocatalysts
** \\ \hline \multirow{7}{*}{LIP} & CS/CNWs & Beads & Tamric acid & EDAC/NHS & Not indicated & Not indicated & [178] \\ \cline{2-8}  & CS-GA-Gly & Beads & No & GA & 34\% of activity after increases & Not indicated & [180] \\ \cline{2-8}  & nM-OA-CS-GA & NPs & No & GA & Not indicated & Not indicated & [180] \\ \cline{2-8}  & CS & Beads & No & GA & 75.2\% of activity after 10 nuses & 85.5\% of activity after 6 months at 5\({}^{\circ}\)C & [185] \\ \cline{2-8}  & Fe\({}_{3}\)O\({}_{4}\)-CS-GA & Micorpatrides & No & GA & 40\% of activity after 10 nuses & 80\% of activity after 6 months at 5\({}^{\circ}\)C & [186] \\ \cline{2-8}  & Mghemite/CS/TPP & NPs & TPP & GA & Not indicated & Not indicated & [189] \\ \cline{2-8}  & Chitin/CS/FeSO\({}_{4}\) & NPs & GA & EDAC/NHS & Not indicated & 90\% of activity after 40 days at 30\({}^{\circ}\)C & [201] \\ \cline{2-8}  & CS-alginate & Micropasules & No & No & No loss of activity after five reuses & Not indicated & [202] \\ \cline{2-8}  & Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\)@ & NPs & No & EDAC/NHS & 85\% of activity after 70\% of activity after 30 days at 4\({}^{\circ}\)C & [203] \\ \cline{2-8}  & CS-GA & Micropasules & No & No & 20\% of activity after five reuses & Not indicated & [212] \\ \cline{2-8}  & CS & - & No & No & 90\% of activity after 42\% of activity after 2 days after 20\({}^{\circ}\)C & [218] \\ \hline \multirow{7}{*}{LAC} & CS & Beads & No & No & 40\% of activity after 100\% of activity after five reuses & 100\% of activity after 30 days at 4\({}^{\circ}\)C & [187] \\ \cline{2-8}  & CS-GA & Beads & GA & No & 20\% of activity after five reuses & 30\% of activity after 30 days at 4\({}^{\circ}\)C & [187] \\ \cline{2-8}  & MnFe\({}_{2}\)O\({}_{4}\)-CS & NPs & No & GA & no loss of activity after five reuses & 30 days at 4\({}^{\circ}\)C & [188] \\ \cline{2-8}  & CS & Beads & No & GP & 35\% of activity after 11 nuses & 32\% of activity after 30 days at 4\({}^{\circ}\)C & [199] \\ \cline{2-8}  & MACS-NIL-Cu & NPs & - & - & 93.2\% of activity after five reuses & 95\% of activity after 30 days at 4\({}^{\circ}\)C & [204] \\ \cline{2-8}  & CA-Ca-SBE & Beads & No & No & 83.1\% of activity after 10 nuses & 92\% of activity after 50 days at 4\({}^{\circ}\)C & [214] \\ \cline{2-8}  & SiO\({}_{2}\)-Ca-CS & - & No & No & 90\%-50\% of activity after four reuses & 70\% of activity after 70 days at 4\({}^{\circ}\)C & [216] \\ \hline \multirow{7}{*}{\(\beta\)-galactosidase} & CS & Microspheres & No & GA & Not indicated & 100\% of activity after 105 days at 4\({}^{\circ}\)C & [179] \\ \cline{2-8}  & CS-GP & Beads & GP & GP & No loss of activity after 25 nuses & Not indicated & [202] \\ \cline{2-8}  & SO\({}_{2}\)-Me-CS & - & No & No & Not indicated & Not indicated & [202] \\ \cline{2-8}  & PANI-CS-Ag & - & No & No & 94\% of activity after 94\% of activity after 10 nuses & 94\% of activity after 60 days at 4\({}^{\circ}\)C & [217] \\ \cline{2-8}  & \(\beta\)-glucosidase & NPs & GA & 6-His tag of enzymes after five reuses & Not indicated & [190] \\ \cline{2-8}  & Fe\({}_{3}\)O\({}_{4}\)-CS/GA/ & NPs & GA & & 10\% of activity after five reuses & 10\% of activity after five reuses & 100\% of activity Based on the presented data, the following trends can be noticed, and brief conclusions made:  
1. There are four main approaches to thepreparation of CS-based supports for the immobilization of enzymes: CS beads optionally crosslinked with different agents; CS capsules typically formed by ionotropic gelation with SA; core-shell NPs consisting of an inorganic core (usually magnetic) covered with CS; membranes;
2. Enzymes can be immobilized usingthe following general approaches: encapsulation into CS-containing gel; covalent binding to the surface of a CS-based support; physical adsorption on the support surface. Among the mentioned approaches, covalent binding seems to be more promising for the development of sustainable biocatalysts, allowing high reusability and storage stability.