Chitin and Chitinases: Biomedical And Environmental Applications of Chitin and its Derivatives

Corresponding Author: 1) Rameshthangam Palanivel, Department of Biotechnology, Alagappa University, Karaikudi 630003, Tamilnadu, India, Email: rameshthangam@alagappauniversity.ac.in, Phone: +91– 9444834424. 2) Palaniappan Ramasamy, DirectorResearch, Sree Balaji Medical College and Hospital, BIHERBharath University, Chennai-600041, Tamil Nadu, India, Email: researchsbmch@gmail.com, Phone: +919442135200


Introduction
Chitin is a natural polymer, first discovered in mushrooms by French Professor, Henrni Braconnot, in 1811. Chitin is the second most abundant biopolymer next to cellulose with an annual production of 10 10 to 10 11 tons 1 . In many respects, chitin is similar to cellulose and is considered to be a derivative of cellulose where the C2 hydroxyl groups were replaced by acetamido residues 1,2 In nature, chitin is found as crystalline microfibrils which form the structural components of many organisms. Chitin serves as a structural and functional material wherever reinforcement and strength are required in a number of living organisms 2 . The commercial value of chitin has dramatically increased recently due to the beneficial properties of its soluble derivatives, which are suitable for a wide variety of industrial applications in biotechnology, agriculture, food processing, cosmetics, veterinary, medicine, dentistry, environment protection, and paper or textile production 3 . Chitin is one of the ubiquitous polymers found in many organisms (Table 1) from cell walls of fungi and algae to cuticle of insect's, shells of mollusks (endoskeleton of cephalopods) and   Honeybees (Insects) 9 Aedes aegypti (Insects) 10 Cancer pagurus (Crab) 11 Carcinus maenas (Crab) 12 Lithodes aequispinus (Golden king crab) 13 Chionoecetes opilio (Snow crab) Erimacrus isenbeckii (Korean hair crab) Paralithodes platypus (Blue king crab) Paralithodes camtchaticus (Red king crab) Chionoecetes bairdi (Tanner crab) Parapenaeopsis stylifera (Shrimp) 14 Penaeus carinatus (Shrimp) 15 Penaeus monodon (Shrimp) 15,16 Litopenaeus vannamei (Shrimp) 17 Jasus lalandii (Lobster) 18 Homarus americanus (Lobster) 19 Sepia offcinalis (Cuttlefish) 20 Loligo vulgaris (Squid) 20 Absidia glauca (Fungi) 21 Absidia coerulea (Fungi) 22 Aspergillus niger (Fungi) 23 Mucor rouxii (Fungi) 24 Phycomyces blakesleeanus (Fungi) 25 Gongronella butleri (Fungi) 26 Absidia blakesleeana (Fungi) 27 Rhizopus oryzae (Fungi) 28 Trichoderma reesei (Fungi) 29 Lentinus edodes (Fungi) 30 differentiate between chitin and chitosan. If the DDA is less than 50%, it is then termed as chitin and if the DDA is greater than 50%, it is termed as chitosan 35

Chitosan
The utilization of chitin may be restricted due to its poor solubility, low porosity, and surface area 45 .

Biomedical Applications
Chitin and its derivatives are biodegradable and biocompatible natural polymers, safe and non-toxic, and bind to mammalian and microbial cells potentially. Here, we discussed some of the potential biomedical applications of chitin and its derivatives (Fig. 7).   In various similar studies COS was proved for its anti inflammatory property in uveitis rats and asthmatic models 95,96 . The recent reports state that, chitin and its derivatives may act as a promising candidate material for treating and preventing inflammation.

Wound Healing Potential
The wound healing is a complex process, which includes hemostasis, inflammation, proliferation, and  Chitinases can be used in the production of single cell protein by utilize the chitinous waste effectively 164 . All together chitinases, CT and its derivatives can be used for the remediation of various organic contaminants from the environment.

Conclusion and Future Perspective
At the outset, this review focused on the recent developments related to biomedical and environmental applications of chitin, chitinases, and chitin derivatives.
In the first part of the review, various methods that have been employed to improve the functionality of chitin have been discussed. Chitin and its enzymes can