Purification and partial characterization of a novel bacteriocin produced by bacteriocinogenic Lactobacillus fermentum BZ532 isolated from Chinese fermented cereal beverage (Bozai)

Abstract

In current study, a novel bacteriocin LF-BZ532 was produced by Lactobacillus fermentum BZ532 that was isolated from Chinese fermented cereal drink (locally called bozai) and identified by 16s rDNA sequencing. The bacteriocin LF-BZ532 was purified by ammonium sulfate precipitation, SP-Sepharose cation exchange chromatography and AKTA purifier RP-HPLC, in succession. Then purified product was subjected to MALDI-TOF MS and designated its molecular mass was 1105.563 Da. Bacteriocin LF-BZ532 was found to have broad antimicrobial spectrum against both Gram-positive and Gram-negative bacteria, including anti-listerial and anti-pseudomonas activity. It was significantly thermostable with 88.19% and 56.98% residual activity at 100 and 121ᴼC (30, 20 min) respectively. Moreover, it was considerably stable at a range of pH (2–8) but all the activity was eliminated against proteolytic (Proteinase K, pepsin and trypsin) enzymes, suggested its peptide nature. Based on above premise, it is proposed that purified LF-BZ532 and its producing strain Lactobacillus fermentum BZ532 significantly proved as potent candidates to be use as a bio-preservative in food industry.