Physicochemical structure of chitin in the developing stages of black soldier fly

Abstract

Black soldier fly can convert organic wastes into their own functional biological macromolecules i.e. chitin that has great potential for biotechnological, biomedical and cosmetic application. The variation in the physiochemical structure of chitin was proved for several insects during metamorphosis stages whereas, it remains unknown for black soldier fly (BSF), a recognized resource insect for industrial production and organic waste management. The current work noted results on how the chitin matrix can undergo physicochemical changes during the developmental phases (larvae, prepupa, puparium, and adults) of BSF. Chitin content was determined around 3.6%, 3.1%, 14.1% and 2.9%, respectively. Fourier transform infrared spectroscopy, thermogravimetric analysis and x-ray diffraction analysis showed that chitin from BSF different stages was all α-chitin with similar thermal stability. The chitin crystalline index increased gradually with development from larvae to adult, 33.09%, 35.14%, 68.44% and 87.92%, respectively. Moreover, it was observed by scan electron microscopy that surface morphology characteristics of chitin vary significantly in developmental phases. These results confirmed that Hermetia illucens is promising for converting organic wastes into valuable biopolymers i.e. chitin and its physiochemical properties in various developmental stages help to determine the related biomedical, biotechnological, cosmetic and functional food utilization potential.