Purification and characterization of a bacteriocin from Lactobacillus rhamnosus

Abstract

The bacteriocin-zrx01 produced by Lactobacillus rhamnosus zrx01 was purified, its basic biochemical characteristics and bacterial antibacterial sensitivity were studied. The bacteriocin-zrx01 was separated and purified using ethyl acetate, AKTA purifier™ 10 protein purifier with HiTrap™ Capto™ Q anion exchange chromatography and Superdex™ 75 10/300 GL gel chromatography. The purity of bacteriocin-zrx01 was analyzed using high performance liquid chromatography. The sensitivity to temperature, pH and enzymes of the purified bacteriocin-zrx01 was measured as the diameter of the antimicrobial ring. The results showed that the purified bacteriocin-zrx01 bacterial antibacterial activity was good, and the specific vitality was raised from the original fermentation broth at 625 to 5330 AU/mg. The bacteriocin-zrx01 had a higher stability at pH 3–9, and the antibacterial activity was the strongest at pH 4. When pH was 9, it still retained 86% of the antibacterial activity of the control group. Bacteriocin-zrx01 was cold-stable at −70 and −20 °C for 30 min. It still retained 57% antimicrobial activity compared with the control after being autoclaved at 121 °C for 30 min. Some enzymes, such as protease K, neutral protease, trypsin, thrombin, alkaline protease and papain, affected its antibacterial activity, but it was sensitive to pepsin, and the diameter of the antimicrobial ring decreased by 50% after 2 h of pepsin treatment. These results showed that the bacteriocin-zrx01 produced by Lactobacillus rhamnosus zrx01 might have a potential as a natural food preservative, although in vivo studies are needed.