Purification and Partial Characterization of a Novel Bacteriocin Synthesized by Lactobacillus paracasei HD1-7 Isolated from Chinese Sauerkraut Juice

Bacteriocins have antimicrobial activities against food-spoiling bacteria and food-borne pathogens. Paracin 1.7, a bacteriocin synthesized by Lactobacillus paracasei HD1-7 isolated from Chinese sauerkraut juice, was studied. Following partial purification with ammonium sulfate precipitation, CM Sepharose Fast Flow, and Sephadex G-10 chromatography, the molecular weight of Paracin 1.7 was about 10 kDa based on Tricine-SDS-PAGE results. A 2.87 fold purified bacteriocin was produced, reaching a final yield of 39.93% and the specific activity of 1.56 × 10(3) AU/mg. The N-terminal amino acid sequence of Paracin 1.7 was VSNTFFA, and the LC/LTQ results revealed that the N-terminal amino acid sequence was similar to that of ABC-type oligopeptide transport system protein and N-acetylmuramoyl-L-alanine amidase. Paracin 1.7 was sensitive to protease K, had antimicrobial activities at a broad pH range (3.0-8.0), and was heat resistant (121 °C for 20 min). Paracin 1.7 from Lactobacillus paracasei HD1-7 is a novel bacteriocin that has potential applications in food preservation.