Biodegradation, Biosynthesis, Isolation, and Applications of Chitin and Chitosan

Abstract

Chitin is a most abundant fibrous matter comprised of polysaccharide carbohydrates. Chitin is a dominant and main building material in the exoskeleton of many living organisms, including arthropods, crustaceans, fungi, and fishes. Chitin strengthens the exoskeleton, and enzymatic and chemical deacetylation by removing an acetyl group is converted into linear polysaccharide chitosan. In nature, chitosan is a carbohydrate acquired from the degradation of the hard skeleton of shellfish, arthropods, and crustaceans. Crustaceans and shellfishes contribute a significant proportion to total chitin used in the food-processing industry, besides having considerable applications in the biomedical field. The organisms that synthesize chitin employed a rigorous and complex enzymatic mechanism for degradation and body homeostasis. The enzyme uridine diphosphate-N-acetylglucosamine (UDPGlcNAc) is important for chitin synthesis; it brings out small chitin polymers, while a hydrolytic chitinase enzyme breaks down the chitin. In nature, the major biotic factor that degrades breaks down and mediates chitin hydrolysis is bacteria. Chitin and chitosan have multiple properties and features, including translucence, pliability, resilience, toughness, biodegradability, biocompatibility, innocuous film formation, revolutionizing the biomedical field. The emerging application of nanotechnology has utilized chitin and chitosan-originated materials to achieve innovations to transform the biomedical field. The multiple chitins and chitosan applications have contributed a major role in the polymer industry, especially in fabricating polymer scaffolds.

Biomedical sciences face many challenges, and the major role chitin and chitosan played in terms of their nano-/microparticles and encapsulation of cargos are interesting. The uniquely designed nanocarriers and microencapsulation techniques are very interesting based on chitin-based materials for effectiveness in delivering drugs, biologics, and vaccines. The encapsulated drugs and nanoparticles are specific to applications, dimension, and cargo-release properties. Chitosan has been used effectively and efficiently in hydrogel solutions, nano-/microparticles, drug and vaccine delivery, antibacterial, wound healing, anticancer, cancer diagnosis, chitin- and chitosan-based dressings, ophthalmology, antibacterial properties, antithrombogenic and hemostatic materials, antiaging cosmetics, antitumor activity, and vaccine adjuvant as customized biochemical properties; therefore it is one of the most critical, essential, and well-researched biomaterials. This book chapter is aimed to thoroughly discuss the biosynthesis, isolation, and applications of chitin and chitosan under various headings.