Research progress on the nutritional value and applications of black soldier fly larvae frass

Black soldier fly larvae (Hermetia illucens L., BSFL) are increasingly utilized in waste management and resource recovery due to their remarkable ability to rapidly degrade and convert organic waste into high-value by-products, particularly larvae frass. This frass is rich in various essential nutrients such as nitrogen, phosphorus, and potassium, as well as substantial amounts of organic matter and trace elements, thereby exhibiting significant potential as a sustainable fertilizer. Moreover, bioactive compounds present in the frass have been reported to enhance soil structure, stimulate soil microbial activity and promote plant growth. Recent researches have made substantial progress in characterizing the physicochemical properties of BSFL frass, identifying its bioactive components, application status as a soil amendment or supplement, and developing strategies to improve its biological stability. However, potential environmental concerns associated with the presence of antimicrobial peptides and emerging contaminants—such as microplastics, antibiotics and antibiotic resistance genes—remain insufficiently studied and warrant further investigation. Therefore, this review provides a comprehensive overview of the nutritional composition, current applications and recent technological advancements in the valorization of BSFL frass. It also critically examines the challenges and future directions in its recycling and resource utilization, with particular emphasis on potential environmental pollutants and their hazards. Suggestions are offered to guide future research and promote the sustainable development of BSFL frass-based applications.