Impact of a Microbial and Physical Predigestion of Food Waste on the Black Soldier Fly Hermetia illucens (Linnaeus, 1758) Larvae Growth and Nutritional Composition

The ability of the black soldier fly Hermetia illucens (L. 1758) to convert biowaste is well established, and research is increasingly focused on optimizing rearing conditions and improving the nutritional profile of larvae. Our study examined the impact of physical (thermal and grinding) and microbial predigestion of a diet on the development (growth and survival rate) and composition (lipids, fatty acids, ash, and proteins) of black soldier fly larvae. We compared the effects of different pretreatments on a single diet to evaluate the potential use of a digester in black soldier fly farming for agro-industrial purposes. This innovative method shows that grinding and digesting a mixture of unsold food and brewery waste (fruits, vegetables, bread, and brewer’s spent grain) using thermophilic microorganisms can produce white larvae weighing 278 mg in 12 days, with 30.66% crude protein while significantly reducing lipid content and saturated fatty acids. These new method and results present promising prospects for biowaste valorization and large-scale insect farming.