Bioconversion to bioresources: Pollutant detoxification mechanisms and circular bioeconomy prospects in black soldier fly larvae composting

The rapid growth of organic waste streams, often contaminated with heavy metals, persistent organic pollutants, and microplastics (MPs), poses significant challenges for waste management and environmental safety. Black soldier fly larvae (BSFL; Hermetia illucens L.) bioconversion is gaining recognition as an innovative approach for waste valorization. Yet, there are still notable gaps in understanding how pollutants are detoxified within BSFL systems and how these processes fit into circular bioeconomy goals. This review explores these mechanisms by describing the fate of pollutants during BSFL composting, emphasizing how detoxification happens through: (i) larval bioaccumulation and enzymatic breakdown, (ii) changes in the gut microbiome, and (iii) interactions with microbial communities in compost. The review analyzes how these pathways influence the immobilization of heavy metals, the breakdown of organic pollutants, and the fragmentation of MPs, thereby affecting the safety of frass. Crucially, these detoxification processes were connected to the valorization of larval biomass (proteins and lipids) and processed frass (as soil amendments), demonstrating a pathway to implement a circular bioeconomy that reduces reliance on landfills and lowers greenhouse gas emissions. Although BSFL bioconversion offers many environmental advantages, challenges such as process scalability, incomplete understanding of contaminant fate, and changing regulations must be addressed. Future research should focus on meta-analyses to evaluate effect sizes and determine key factors influencing results. By clarifying these mechanisms and the potential for valorization, this review advocates for the safe, scalable adoption of BSFL technology as a vital part of sustainable waste management aligned with the global Sustainable Development Goals. • BSFL reduced heavy metals, pesticides, and microplastics during composting. • Composting with BSFL reduces waste volume by half and cuts greenhouse gas emissions. • BSFL frass combined with compost acts as a nutrient-rich and safe organic fertilizer. • Review outlines pollutant removal mechanisms in the BSFL bioconversion process. • Key gaps and future directions in BSFL composting are systematically reviewed.