Chemical viz biological method for the extraction of chitin and chitosan from adults of the black soldier fly (Hermetia illucens)

The black soldier fly -BSF- (Hermitia illucens) offers an environmentally responsible and sustainable substitute for chitin and chitosan, which are valuable polysaccharides with broad applications in pharmaceuticals, agriculture, and food technology. This study aims to compare chemical and biological techniques to isolate chitin and chitosan from adult flies, evaluating their antibacterial properties. In the chemical method, demineralization and deproteinization were achieved using HCl and NaOH, whereas the biological method employed protease-producing Streptomyces spp. for protein removal and Lactobacillus acidophilus for demineralization. Biological extraction produced higher yields of chitin (32%) and chitosan (26.6%) than chemical extraction (29% and 23%, respectively). Analysis using FTIR confirmed that distinctive functional groups were present and effective deproteinization, with biological samples retaining better structural integrity. XRD verified the existence of α-chitin in both techniques, exhibiting higher crystallinity in the chemical extracts, favoring industrial uses, and more native structures in the biological extracts, suitable for biomedical applications. SEM revealed fibrous and porous morphologies in chitin extracted by the biological method, while chitin extracted by the chemical method appeared denser. Biologically derived chitosan exhibited high antibacterial properties, particularly towards Staphylococcus aureus and Klebsiella pneumoniae. These findings highlight biological extraction as a sustainable strategy that improves yield, preserves bioactivity, and broadens the potential of BSF for advanced applications.