Microbial Valorization of Chitinous Bioresources for Chitin Extraction and Production of Chito-Oligomers and N-Acetylglucosamine: Trends, Perspectives and Prospects

Abstract

Chitin, the crystalline polymer of N-acetylglucosamine (GlcNAc) is the world’s second most abundant carbohydrate and principal structural component of cell wall of fungi, yeasts and algae, insect exoskeletons, shells of crustaceans and the microfilarial sheath of nematodes. GlcNAc is present in peptidoglycan, hyaluronic acid and keratin sulfate. In nature, chitin rich waste biomass get re-utilized by an array of microbes producing chitinases and proteases, but the presence of the microbes as well as activity of the enzymes depend on the abundance of the bioresource. Chitin polymer, chito-oligomers and GlcNAc have engrossed colossal attention due to their innumerable potential applications in food, biomedicine, pharmaceuticals, agriculture, cosmetics and environmental cleanup. Owing their immense and versatile appliances, extraction of chitin and production of chito-oligomers and GlcNAc in large scale is necessary to meet the market demand. In this context, chemical extraction/degradation of crustacean shell at elevated temperature is the traditional practice results in the formation of undesired byproducts, creates large quantities of toxic waste as well as associated with high cost, low yield and also deteriorates environmental health. In this perspective, microbial biotransformation and enzymatic treatment are alternative environment friendly ‘green technology’ for generation of chitin, chito-oligomers and GlcNAc in large scale in economical way by valorizing natural chitinous bioresources using potential organic acid, chitinase and protease producing microbes. Moreover, genetic manipulation and metabolic engineering was implemented in recent ages. Altogether, in the present assignment, cutting edge strategies of bioextraction of chitin and production of chito-oligomers and GlcNAc by microbial means as well as their multifaceted appliances in biological and biomedical sector are thoroughly discussed.