Biowaste treatment using black soldier fly larvae: Effect of substrate macronutrients on process performance

Black soldier fly larvae (BSFL) process is emerging as a promising alternative for the treatment of biowaste. Process performance (such as survival rate - SR and waste reduction efficiency - RE) depends on several factors (e.g. nutritional quality of the substrate) which need to be controlled. The nutritional quality of the substrate can be related to the overall concentration and relative abundance of dominant macronutrients, such as proteins (P), non-fibre carbohydrates (NFC), and lipids (L). Assessing how these substrate quality parameters influence the process performance is fundamental to determining the suitability of a given substrate to be treated by using BSFL and to optimise the process performance. The aim of this study was to gather, integrate, and elaborate published literature to present a comprehensive understanding of how the nutritional substrate quality, impact the process performance in terms of RE and SR. A systematic literature review was conducted by using the PRISMA methodology. The results were graphically elaborated to obtain a simple tool useful for a rapid prediction of the individual substrate suitability to BSFL process and for the evaluation of optimal mixture of different substrates to achieve desired outcomes. A good nutritional quality of substrate (when SR>80% and RE>40%) can be generally identified based on the relative abundance of macronutrients (X-P, X-NFC, and X-L), when X-L < 0.6, X-P > 0.05, and when X-P > 0.5 if X-NFC>0.2. Additionally, when X-P ranges between 0.05 and 0.15 a good quality substrate occurs if X-NFC > X-L.