Enhancing Salmonella Inhibition in Black Soldier Fly Larvae (Hermetia illucens L.) Conversion by Bioaugmentation With...

Black soldier fly larvae (BSFL) can efficiently convert organic waste into biomass and reduce pathogenic bacteria in organic waste. The microbial composition of the substrate and the gut of BSFL is a pivotal factor in determining the efficacy of BSFL in pathogen elimination. However, there are insufficient data on the gut microbiology of BSFL in relation to pathogen inhibition. To address this gap, we investigated the dynamics of Salmonella during the conversion of chicken manure by BSFL and examined the role of intestinal bacterial communities and core bacteria in reducing Salmonella levels. The results indicate that BSFL treatment can reduce the amount of Salmonella in chicken manure, with the gut microbiome of the BSFL playing a crucial role in this reduction. Combining metagenomic analysis with culturomics methods, we isolated 158 strains from the larval gut, in which seven gut bacteria belonging to the genus Bacillus can promote BSFL to reduce Salmonella. In reinoculation and validation experiments, the combination of BSFL and Bacillus velezensis A2 enhanced the elimination of Salmonella from chicken manure and larvae. This study provides insight into how BSFL can reduce pathogenic bacteria in chicken manure and suggests that pairing BSFL with functional microorganisms can improve the biosafety of organic waste conversion by BSFL.