Abstract:

The strain Br26 with antibacterial activity was screened from fermented garlic. Different proteases were selected
to determine whether the strain is bacteriocin-producing bacterium. Subsequently, the induction efficiency of bacteriocin
synthesis by the fermentation supernatant of Br26 alone and co-cultures with other lactic acid bacteria was determined. The
results showed the inhibitory activity of the fermentation supernatant of Br26 decreased after treatment with pepsin and
papain, respectively, suggesting that the antimicrobial substance is bacteriocin. The strain was identified as Weissella sp.
Br26 by 16S rDNA gene sequence homology analysis. The inhibitory activity disappeared when Br26 was cultured in 1/4
MRS at 42 ℃; however, it was significantly increased after adding fermentation supernatants at different growth phases,
indicating that bacteriocin biosynthesis can be self-induced. On the other hand, although there were no significant changes in
the pH values of fermentation supernatants, bacteriocin activity of Br26 was significantly increased after co-culturing with
Lactobacillus crispatus, Lactobacillus helveticus, Lactobacillus paracasei and Leuconostoc mesenteroides, indicating that
the synthesis of bacteriocin can also be induced by other lactic acid bacteria. In summary, bacteriocin synthesis of Weissella
sp. Br26 can be induced by itself and other lactic acid bacteria.

Key words: Weissella sp. Br26, bacteriocin, quorum sensing