Microbial degradation of chitin (Enzymes, Steps, Mechanisms)


Chitin is a natural polysaccharide that is widely distributed in nature, found in the cell walls of fungi, the exoskeletons of arthropods, and certain structures of other invertebrates . It is also synthesized by some fish and amphibians. Chitin is the second most abundant biopolymer in the world, after cellulose , and it has various industrial and medical applications as a flocculating agent, wound-healing agent, thickener, stabilizer, ion-exchange resin, membrane, binder, and sizing and strengthening agent .

Chitin is a polymer of N-acetylglucosamine units linked together by β- (1→4)-glycosidic bonds . It has a similar structure to cellulose, except that one hydroxyl group on each monomer is replaced by an acetyl amine group . This modification allows for increased hydrogen bonding between adjacent polymers, giving the chitin-polymer matrix increased strength. Chitin can exist in different forms or conformations depending on the orientation of the polymer chains and the degree of acetylation . The most common forms are α-chitin, β-chitin, and γ-chitin.

Chitin is a versatile biomaterial that can be modified chemically or biologically to produce derivatives with different properties and functions . One of the most important derivatives is chitosan, which is obtained by deacetylation of chitin . Chitosan is more soluble than chitin and has antimicrobial and hydrating properties that make it useful for biomedical applications .

Chitin is a biodegradable and biocompatible polymer that does not accumulate in the biosphere as it is degraded by various microorganisms that produce chitinolytic enzymes . These enzymes break down the glycosidic bonds in chitin and release smaller oligomers or monomers that can be utilized by the microorganisms or other organisms as a source of carbon and nitrogen . Chitin degradation plays an important role in the carbon and nitrogen cycles in nature and also affects the immune responses of plants and animals.

In summary, chitin is a remarkable biopolymer that has many biological and ecological roles as well as potential applications in various fields. In this article, we will discuss the structure of chitin and its different forms, the enzymes involved in chitin degradation, the microorganisms that degrade chitin, the factors affecting chitin degradation, the process of chitin degradation, and the mechanisms of microbial degradation of chitin.