Abstract:
Chitin is the second most widely found natural polymer next to cellulose. Chitinases
degrade the insoluble chitin to bioactive chitooligomers and monomers for various
industrial applications. Based on their function, these enzymes act as biocontrol agents
against pathogenic fungi and invasive pests compared with conventional chemical fungicides and insecticides. They have other functional roles in shellfish waste management,
fungal protoplast generation, and Single-Cell Protein production. Among the chitinases,
thermophilic and thermostable chitinases are gaining popularity in recent years, as they
can withstand high temperatures and maintain the enzyme stability for longer periods.
Not all chitinases are thermostable; hence, tailor-made thermophilic chitinases are designed to enhance their thermostability by direct evolution, genetic engineering involving
mutagenesis, and proteomics approach. Although research has been done extensively on
cloning and expression of thermophilic chitinase genes, there are only few papers
discussing on the mechanism of chitin degradation using thermophiles. The current
review discusses the sources of thermophilic chitinases, improvement of protein stability
by gene manipulation, metagenomics approaches, chitin degradation mechanism in
thermophiles, and their prospective applications for industrial, agricultural, and pharmaceutical purposes.
