Insects an innovative source of chitosan: possible applications

The polysaccharide chitin is one of the most abundant natural polymers and it is the major structural component of the arthropod exoskeleton and the cell wall of fungi and yeasts. Due to their properties, like biodegradability, bio-compatibility, non-toxicity, adsorption and antimicrobial activity, chitin and its main deacetylated derivative, chitosan, have a great economic value and they are molecules of great interest as new functional biomaterials, finding many applications in the industrial and biomedical field. The main commercial source of chitin and chitosan is crustaceans’ exoskeleton. The extraction of chitin from insects, a promising alternative source, has received relatively little attention. Among insects, Hermetia illucens is a promising source of chitin. This insect is the subject of increasing research in the scientific world thanks to its ability to convert organic waste into larval biomass rich in proteins and lipids of high biological value. Currently, the chitin contained in the exoskeleton of last instar larvae, pupae and adult flies constitutes a by-product of the bioconversion process aimed at the production of animal feed. All the available protocols for chitin and chitosan extraction from insects involve the use of chemicals, mainly acids for minerals removal, bases for both proteins hydrolyzation and chitin deacetylation, and various reagents for depigmentation. The present study focuses on chitin extraction, and its deacetylation into chitosan, from the exoskeleton of H. illucens at different developmental stages, in order to make the most of a resource not yet fully exploited. The obtained product will be investigated for different possible applications.