Purification and Characterization of a Bacteriocin, BacBS2, Produced by Bacillus velezensis BS2 Isolated from Meongge Jeotgal

Bacillus velezensis BS2 was isolated from meongge (common sea squirt) jeotgal, a Korean fermented seafood, and produces a bacteriocin, BacBS2, which strongly inhibits Listeria monocytogenes and Bacillus cereus. BacBS2 was partially purified by Q-Sepharose column chromatography after ammonium sulfate precipitation of the culture supernatant, then further purified by Sephadex G-50 column chromatography. Partially purified BacBS2 was estimated to be 6.5 kDa in size by Tricine-SDS PAGE and activity detection by gel-overlay. Enzyme treatment and FT-IR spectrum of partially purified BacBS2 confirmed its proteinaceous nature. BacBS2 was fully stable at pH 4-9, and half of activity was retained at pH 1-3. Full activity was retained after exposure to 80 degrees C for 15 min, but half of the activity was retained upon exposure to 90 degrees C for 15 min or 100 degrees C for 10 min. BacBS2 inhibited L. monocytogenes by bactericidal mode of action. B. velezensis BS2 and its BacBS2 seem useful as biopreservatives for fermented foods such as jeotgal.