Insights on Lipid Biodegradation in Domestic Biodegradable Waste at a Full-scale Black Soldier Fly Larvae (Hermetia illucens L.) Bioconversion

Abstract The lipids in the domestic biodegradable waste (DBW) pose a challenge to resource regeneration, and few studies have examined the evolution of lipid profiles during the process of black soldier fly larvae (Hermetia illucens L., BSFL) bioconversion. This study aimed to explore the dynamic features of lipid fraction and their associated responses of microbial community succession in residue during a full-scale BSFL bioconversion. Data showed that the lipid content decreased by95%, while the seed germination index increased by 20% through the synergistic effects of BSFL and microbiota. The results of spectral and Gas chromatography-mass spectrometry showed that free fatty acids and medium-chain fatty acids were given first priority in degrading in larval and microbial coexistence systems, resulting in the relative accumulation of sterols. The lipid content (71.1%, P = 0.002) was the prime environmental factor that promoted the succession of the bacterial community. The diversity and structure of the bacterial community varied at different stages of the bioprocess, where BSFL induced Corynebacterium, Marinobacter, and Brevibacterium. EC: 4.2.1.17 (Enoyl-CoA hydratase) and EC: 1.1.1.35 (3-hydroxyacyl-CoA dehydrogenase) were the key lipid metabolic enzymes, promoting the degradation and transformation of materials and lipids. The synergistic effect of BSFL and microbiota promotes lipid metabolisms in DBW, which is conducive to the sustainable utilization of BSFL biotechnology to convert wastes into high-value resources.