Influence of bacteriocin-producing Bacillus strains on quality characteristics of fermented soybean product with biogenic amine-forming lactic acid bacteria

This study evaluated the antibacterial activity of bacteriocin produced by Bacillus strains against biogenic amines (BA)-forming lactic acid bacteria (LAB), and the applicability of desirable strains as Bacillus starters for safety and quality improvement of fermented soybean products. The BA-forming ability of the tested LAB in amino acid decarboxylase broth was mostly strain specific rather that species specific. The bacteriocin produced by specific Bacillus strains: Bacillus sp. DB407, Bacillus licheniformis DB612, and Bacillus subtilis DB821 may play a contributory role in the inhibiting the growth of BA-forming strains. In fermented soybean products manufactured using different starter cultures, there was a significant reduction (p < 0.05) in the cell counts of LAB by application of a mixed culture containing B. subtilis DB821, which showed the highest antimicrobial activity. Specifically, B. subtilis DB821 was highly efficient in reducing accumulation of cadaverine, tryptamine, and tyramine produced by Enterococcus faecium D12 and Enterococcus faecalis D51 during soybean fermentation. In conclusion, the bacteriocin-producing Bacillus strains such as Bacillus sp. DB 407, B. licheniformis DB612, and B. subtilis DB821 can be used as a starter culture for the production of BA-controlled soybean products and for the enhancement of the quality and safety of fermented foods.

Automated summary

This study evaluated the antibacterial activity of bacteriocin produced by specific Bacillus strains against biogenic amines-forming lactic acid bacteria, and found that the strains could play a contributory role in inhibiting the growth of such bacteria. Using these Bacillus strains as starter cultures can enhance the safety and quality of fermented soybean products by effectively reducing the accumulation of biogenic amines.