The application of deep eutectic solvents for greener extraction of chitin from black soldier flies (Hermetia illucens)

Chitin is an abundant biopolymer that is primarily extracted from aquatic seashells using harsh chemicals. Black soldier flies (BSF) are regarded as a promising alternative and sustainable resource for chitin. BSF have a short life cycle and can be fed organic food waste, thereby enhancing circular economy benefits. Specifically, the use of BSF results in an allergen-free chitin/chitosan product, unlike those derived from aquatic sources. This study investigated two stages of the BSF life cycle for chitin extraction: the adult fly and the pupa. Chitin was extracted using a green choline chloride– malonic acid deep eutectic solvent (DES) under various process conditions. Three process parameters were assessed: extraction time, temperature, and BSF:solvent mass ratio. The experiments were designed using Box–Behnken Design (BBD) via Response Surface Methodology (RSM), which evaluated the effects of each process parameter on chitin yield and optimised the process conditions to maximise yield. Given differences in exoskeletal composition across life stages, results showed that chitin yield from adult BSFs was different than a the pupas stage of life. Optimal extraction conditions were identified yielding >25% of chitin. These findings demonstrate BSF’s strong potential as a sustainable feedstock for allergen-free chitin production.