Chitosan isolated from black soldier flies Hermetia illucens: Structure and enzymatic hydrolysis

This study aims to elucidate the biochemical properties of chitosan isolated and purified from larvae of black soldier flies Hermetia illucens to discover and utilize new eco-friendly chitin material. The productivity of chitin obtained from the larvae of black soldier flies H. illucens was found to be approximately 5.00 ± 0.002%. These chitins were converted to chitosan by chemical treatment with a yield of about 93 ± 0.16%, and a deacetylation degree of 85.71 ± 0.24% was confirmed. The average molecular weight of the purified chitosan designated to Hi-Cs was estimated to be approximately 680-kDa by high-performance gel permeation chromatography (HPGPC). The primary chemical structure of the Hi-Cs and its hydrolysates designated to active molecule chitosan (AMC) was identified by Fourier-transform infrared spectroscopy (FT-IR), 1H Nuclear magnetic resonance (1H NMR), and Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry analyses, respectively. The significant antioxidant activity of AMC was confirmed through the ABTS radical removal activity analysis. To the best of our knowledge, this is the first report on the structural analysis and antioxidant activity of chitosan isolated and purified from larvae of black soldier flies H. illucens.