Black Soldier Fly Culture as a Source of Chitin and Chitosan for Its Potential Use in Concrete: An Overview.

Chitin is one of the most abundant biopolymers in nature and is found mainly in the exoskeletons of crustaceans and insects, in the cell walls of fungi, and in some species of mollusks. Chitosan is a derivative of chitin; it is much more accessible and has a broader range of applications, including improving the quality of materials such as films, plastics, and concrete. The rheological properties of chitin and chitosan refer to their behavior against deformation and flow and their ability to resist structural changes under mechanical stress conditions. These properties are fundamental in applications where the aim is to control the texture, viscosity, and handling of these biopolymers. Three types of methods for the extraction of chitin and chitosan can be classified: the first is the chemical method, which presents high yields but uses reagents that generate toxic residues; the second is the biological method, which takes advantage of chemical reactions of microorganisms but in some cases has low yields compared to chemical extraction; and the third is the enzymatic method, which uses reagents with a low production of toxic residues. However, low extraction yields are also reported. One of the primary sources of chitin and chitosan is the residue of shellfish and crustaceans. However, a new source of obtaining these compounds is the black soldier fly, which has the same yields of biopolymers as shellfish. In addition, this is a residue of the black soldier fly larvae culture, where protein, oil, and biofertilizers are generated by the bioconversion of organic waste. This work proposes the black soldier fly as an alternative source for extracting chitin and chitosan, using organic methodologies that do not generate toxic residues and have high yields. Including these biopolymers in concrete elaboration could have positive results in terms of flexibility, compressive strength, and workability.