Obtention and Characterization of Chitosan from Exuviae of Tenebrio molitor and Sphenarium purpurascens.

Chitosan is a versatile biopolymer with applications in various industries due to its biocompatibility and biodegradability. While crustacean shells are the primary source of chitosan, the extraction process can be environmentally taxing. This study focuses on evaluating chitosan from Tenebrio molitor and Sphenarium purpurascens, two insect species that offer a more sustainable alternative and require fewer resources for cultivation and produce large amounts of chitin-rich biomass. The acid-alkali method was applied using three experimental conditions (M1, M2, and M3) that involved modification in the demineralization, deproteinization, and deacetylation steps. The chitosan samples were characterized by determining the degree of deacetylation, solubility, molecular weight, antimicrobial activity, and swelling capacity and furthermore by measuring deproteinization and impurity content. Also, Fourier-transform infrared spectroscopy (FTIR) analysis was also performed on the chitosan samples. Samples M3 from the exuvia of T. molitor (DD 55.62% ± 0.79 and solubility 24.13% ± 2.07) and M1 from S. purpurascens (DD 61.86% ± 4.98 and solubility 27.31% ± 1.87) presented the best performance. The molecular weight was calculated between 75 kDa and 118 kDa. On the other hand, data obtained for swelling tests suggested that the film obtained from sample M1 (T. molitor, 5.07% ± 0.11) proved to be more resistant to degradation in an aqueous environment, suggesting that this chitosan could be used for designing a film with high resistance. By exploring these insect sources, this research aims to contribute to the development of chitosan production practices, with potential applications in water treatment, biomedicine, and food packaging, thereby expanding the availability and uses of this valuable biopolymer.