Revealing the role of selected microbial fermentated sericulture waste on the transcriptional profiling of the black soldier fly (Hermetia illucens) larvae

Sericulture waste is one of the highly producing wastes, which is causing great challenge to the industries and environment at global level. Black soldier fly larvae (BSFL) offer a promising solution for organic waste management by converting it into insect protein. In this study, we aimed to develop a selected microbial fermented method for the utilization of sericulture waste to feed BSFL and provide biological basic for the underlying mechanisms. Our results revealed that the larvae reared on different selected microbial fermented sericulture waste had positive effects on body weight, survival rate, substrate consumption rate, substrate conversion rate, and total biomass,. Microbiome analysis revealed that the larvae reared on sericulture waste fermented with most effective combination of microbial strains (B. subtilis, B. licheniformis and E. faecalis) (FSW) significantly altered the microbial community in the BSFL gut, with increased abundances of the commensal genera, such as Miniimonas, Enterococcus, Companilactobacillus, Bacteroides, Vagococcus, Bacillus, and Sedimentibacter, having positive roles in maintaining metabolic processes, triggering immune responses, and eliminating pathogens. In contrast, unfermented group (UFSW) had increased abundances of the genera (Providenicia, Klebsiella, Escherichia, Brucella, and Enterobacter) those are pathogenic and harmful for humans and other hosts. COG functional prediction analysis also showed that the gut microbiota of FSW group had high abundances of metabolic pathways, defense mechanism, and signal transduction mechanism. Transcriptome analysis revealed that highly abundant of the upregulated genes functionally associated with the pathways involved in metabolism, immune mechanisms, and signal transduction mechanisms in FSW group. These findings underscore the pivotal role of selected microbial fermentation using sericulture waste as feed in enhancing BSFL growth dynamics, altering gut microbial shifts, and transcriptional profiles beneficial for metabolic processes and immune responses, thus offering a sustainable solution for organic waste management.