Characterization of multiple bacteriocin-producing Lactiplantibacillus plantarum PUK6 isolated from misozuke-tofu

Abstract

Multiple bacteriocin-producing Lactiplantibacillus plantarum PUK6 was isolated from misozuke-tofu, tofu pickled in miso, a traditional fermented food that has a production history of more than 800 years in the Kuma district of Kumamoto Prefecture, Japan. The PUK6 strain could grow at below 7.5% NaCl and produced both D- and L-lactic acids. In addition, it exhibited potential probiotic properties, including resistance to gastric acid and a cholesterol-lowering effect. Bacteriocins produced by the PUK6 strain were purified from the culture supernatant by ammonium sulfate precipitation, dialysis, Sep-Pak Plus tC18, and reversed-phase high performance liquid chromatography (RP-HPLC). Three peaks with high antimicrobial activity were obtained by RP-HPLC. Based on amino acid sequencing and genetic analysis by PCR, they were considered to be plantaricins A, EF, and NC8, or similar substances.