Opportunities for Organics Valorisation in a Circular Economy: Substrate Sensitivity of Black Soldier Fly (Diptera: Stratiomyidae) Larvae Production

Abstract

Black Soldier Fly Larvae (Hermetia illucens, BSFL) are promising tools for organic waste valorisation in the circular economy, capable of upcycling a wide variety of organic materials into sustainable bio-based products. However, the quality and process performance of BSFL production are highly dependent on the substrate used. This poses challenges for the use of waste-based substrates, which are often heterogenous, poorly defined, and inconsistently available. This thesis aids in addressing this problem by investigating the influence of substrate properties on BSFL production. It combines a comprehensive literature review, controlled growth trials, and mixed-integer linear programming to provide a holistic understanding of the influence of substrate properties on BSFL quality and process performance. The research explores various substrate properties, including carbohydrate and fibre profiles, protein and carbohydrate contents, and contamination with perfluorooctanoic acid (PFOA). Experimental studies reveal that substrate carbohydrate profiles significantly influence BSFL growth, nutritional composition and substrate conversion efficiency. The concentration and source of fibre components are also demonstrated to influence BSFL growth, nutritional composition and fibre digestibility. Regarding substrate contamination, larvae survival and growth show resilience to PFOA exposure, a contaminant found in agricultural residues and water sources. The developed mixed-integer linear programming model, demonstrated through a case study of New South Wales, Australia, highlights the implications of substrate sensitivity for the logistics of large-scale BSFL production. This research enhances our understanding of how substrate properties influence BSFL quality and production performance. Such understanding is valuable for the formulation of waste-based substrates, enabling BSFL production to align with the principles of the circular economy.