Black Soldier Fly Larvae for Organic Waste Valorization: Environmental Benefits, Contaminant Risks, and Circular Bioeconomy Readiness

The black soldier fly (Hermetia illucens, BSF) has emerged as a promising biological platform for converting organic waste into recoverable resources, including insect protein, lipids, frass fertilizer, biodiesel precursors, and biomaterials. Although previous reviews have described BSF larvae as efficient agents of waste reduction or alternative feed production, fewer have integrated larval–microbial bioconversion mechanisms with product quality, contaminant fate, environmental performance, economic feasibility, and regulatory readiness. This review addresses that gap by evaluating BSF-mediated waste management as a decision-oriented circular bioeconomy system. We synthesize evidence on how feedstock composition, larval physiology, gut-associated microbiota, environmental conditions, and substrate pretreatments influence bioconversion efficiency and downstream product value. We further examine how these biological and operational variables interact with greenhouse gas mitigation, frass fertilizer performance, biodiesel and chitosan production, techno-economic constraints, and safety concerns related to pathogens, heavy metals, microplastics, and per- and polyfluoroalkyl substances. By distinguishing well-supported applications, such as clean organic waste and manure valorization, from emerging or uncertain pathways, this review clarifies the current readiness of BSF technologies and identifies areas where claims remain insufficiently validated. The resulting synthesis provides a framework for linking ecological principles with applied engineering, risk assessment, and policy considerations, thereby advancing BSF systems from descriptive promise toward safe, scalable, and evidence-based implementation.