Abstract: Bacteriocin-producing strain LS1 was isolated from Chinese sauerkraut juice and it was identified as Lactobacillus pentosus by 16S rRNA gene sequencing. The bacteriocin was separated from the fermentation supernatant of this strain by ammonium sulfate precipitation, desalted and purified by sequential column chromatography on Sephadex G-10, SP Sepharose Fast Flow, and Superdex 30 Increase. The specific activity of the purified bacteriocin was 1 238.1 AU/mg, which was 110.5 times higher than before the purification. The molecular mass of the bacteriocin was 1 123.8 Da and its N-terminal amino acid sequence was ACDFCFCGMK as determined by liquid chromatography-ion trap tandem mass spectrometry (LC-MS/MS). Pentocin LS1 showed a bacteriostatic activity against some Gram-negative and positive food spoilage bacteria. In addition, pentocin LS1 still retained 80.2% of its original antibacterial activity after being heated at 100 ℃ for 15 min, had strong activity in the range of pH 2.0-8.0, and was sensitive to proteolytic enzymes but insensitive to amylase, lipase catalase, and some chemical reagents. The results showed that pentocin LS1 can be potentially applied in food preservation.

Key words: Lactobacillus pentosus; purification; bacteriocin; characteristics