Untargeted metabolomics and PacBio analysis on bioactive components and microbial community in co-fermentation of black soldier fly larva

Abstract

Fermentation can enhance nutritional value and safety of insect protein, this study utilized probiotic Bacillus subtilis (B. subtilis) and complex enzyme containing chitinase and protease to ferment the paste of Black Soldier Fly larva (BSFL), decomposing anti-nutritional factor chitin and protein in paste while inhibiting the proliferation of harmful microorganisms. The result indicated a 40 % degradation of chitin after fermentation, accompanied by an increase in the variety and quantity of amino acids and peptides, functional substances such as raffinose and cucurbitacin significantly increased, while the levels of antibiotics such as erythromycin and ofloxacin had decreased; after fermentation, there is a significant difference in the microbial distribution between bacteria, co-fermentation and CK, the indigenous microbiota of BSF and pathogenic bacteria such as Klebsiella pneumoniae and Clostridiaceae bacteria were significantly inhibited, anaerobic bacteria, including Anaerosalibacter, Caldicoprobacter and Tissierella, exhibit a marked increase; significant changes are detected in the carbon sources, amino acids, and key enzymes related to other metabolic pathways of B. subtilis during the fermentation process. Overall, we have developed a method for fermenting BSFL paste, aiming at enhance its probiotic properties, nutritional value, and safety. This study provided groundwork for utilizing fermented insects as a novel protein source for food and fodder.