Spent mushroom substrates as feed for black soldier fly larvae: Opportunities and constraints

Abstract

The rising global demand for food and animal feed, driven by improved living standards, has intensified the search for sustainable alternatives. Among the emerging solutions, insects have gained significant attention as a viable source of food and feed. The first part of this dissertation explores the potential of insects in addressing global food and feed challenges. It provides an overview of edible insect species, relevant EU regulations, and the current state of insect production, including the key challenges faced by producers. The core of this dissertation centers on the black soldier fly (BSF, Hermetia illucens), a species renowned for its rapid biomass conversion and efficient feeding behavior. My research is presented in three publications: The review paper outlines critical factors influencing optimal BSF production, highlighting biological, environmental, and operational parameters that enhance efficiency and scalability. In the second paper, I investigate the use of spent mushroom substrate (a by-product of the mushroom industry) as an alternative feed for BSF larvae, partially replacing conventional chicken feed. The experiment evaluates the effects of varying larval densities and replacement ratios on larval growth and substrate conversion. Building upon the previous study, the third paper further optimizes larval density and substrate moisture levels. It also assesses how experimental outcomes vary across different laboratory scales, providing insights into the scalability and reproducibility of results. Together, these studies demonstrate the potential of using agricultural by-products, such as spent mushroom substrate, to sustainably rear BSF larvae, contributing to waste valorization and circular food systems.