Preparation and characterization of chitin and chitosan from different parts of desert locust (Schistocerca gregaria)

Abstract

In this work, chitin was extracted using a single step of deproteinization from the whole locust and its different morphological parts (thorax, legs, abdomen, head and wings). All chitins present an α structure with contents of 10 to 12% and high degrees of acetylation (DA) (92–96%). Physicochemical differences are observed among the chitins from the different parts, particularly in terms of crystallinity indexes (54–72%), molar masses Mv (537,000–672,000 g·mol⁻¹) and surface morphology (fibrous or porous). The N-deacetylation of chitins from the different parts was carried out using KOH in an anhydrous medium (Broussignac process). Other tests using NaOH in an aqueous solution (Kurita process) were also applied to the chitin from the legs. The results show that it is possible to valorize the desert locust by preparing highly deacetylated chitosan (4–14%) with remarkably low to relatively high Mv (11,000–123,000 g·mol⁻¹), depending on the process used.