Patterns of biogenic amine during broad bean paste fermentation: microbial diversity and functionality via Bacillus bioaugmentation

Broad bean paste is a high nitrogen and high salt traditional Chinese condiment, which triggers biosynthesis of nitrogen hazards like biogenic amines (BAs). Mechanisms of association and applied research of functional safety and community assembly within multiple-microbial fermentation are currently lacking. Here, bioaugmentation was performed based on the profiles of BAs accumulation and microbial succession to evaluate the functional variation within broad bean paste fermentation.Putrescine, spermine, and spermidine were the main BAs during traditional broad bean paste fermentation. Staphylococcus, Streptococcus, Lactococcus, Lactobacillus, Leuconostoc, and Bacillus were the predominant bacteria, whereas Aspergillus and Zygosaccharomyces dominated in fungal species, and community structure shifted upon salt exposure. PICRUSt software uncovered that Bacillus contributed significantly (>1%) to the amine oxidase gene family. Bacillus amyloliquefaciens 1-G6 and Bacillus licheniformis 2-B3 were screened to perform the bioaugmentation of broad bean paste, which achieved a 29% and 16% BA decrease respectively. Interaction network analysis showed that Cronobacter and Lactobacillus were significantly negatively correlated with Bacillus (ρ = -0.829 and ρ = -0.714, respectively, P < 0.05) in the B. amyloliquefaciens 1-G6 group, and Staphylococcus and Buttiauxella were inhibited by Bacillus (ρ = -0.657 and ρ = -0.543, respectively, P < 0.05) in the B. licheniformis 2-B3 group.The synergism of amine oxidase activity and microbial interactions led to the decline of BAs. Thus, this study improves our understanding of the underlying mechanisms of microbial succession and functional variation to further facilitate the optimization of the fermented food industry.