Microbial chitinases for chitin waste management

Abstract

Chitin is a major structural component of fungi and exoskeleton of insects, crustaceans and other arthropods. It is an insoluble, unbranched, linear chain of β-1, 4-linked N-acetyl D-glucosamine residues and is the second most abundant renewable carbohydrate polymer in nature after cellulose and first in marine environment. The annual production of chitin in aquatic biosphere is around 1011 ton. Chitinases produced by chitinolytic bacteria have the potential to convert this waste to pharmaceutically valuable end products such as N-acetyl glucosamine and chitooligosaccharides, and are viable alternatives of chemical processes currently used for the purpose. Chitinases from different bacteria, fungi, plants and animals are glycosyl hydrolases which degrade the insoluble chitin in to soluble chitooligosaccharides and glucosamine. Chitooligosaccharides possess antitumor, antifungal, antibacterial and immuno-enhancing effects. Antagonistic bacteria and chitinases have been exploited as potential biocontrol agents against fungal pathogens in plants. The growing number of application areas for chitin and chitin-derived products demand an equally diverse array of chitin-modifying enzymes for specific needs. The chapter will focus on the applications of chitinolytic enzymes from microbial sources and their possible applications, with special focus on conversion of large quantities of the chitinous substrates into useful biological products.