Characterization of the Psychrotrophic Lactic Acid Bacterium subsp. LS4 Isolated from Kimchi Based on Comparative Analyses of Its Genomic and Phenotypic Properties.

With the aim of developing a new food starter culture, twenty-three psychrotrophic lactic acid bacteria (LAB) were isolated from 16 kimchi samples. One strain, subsp. LS4, which had typical psychrotrophic characteristics, was selected, and its phenotypic and genomic properties as a starter culture were investigated. The complete genome of LS4 consisted of one circular chromosome (1,988,425 bp) and two plasmids (19,308 bp and 11,283 bp), with a guanine-cytosine content of 36.8%. LS4 could grow at 5 °C but not at 37 °C, and maximum cell growth was obtained at 15~25 °C. LS4 did not show any harmful characteristics such as hemolysis, undesirable enzyme activities, biogenic amine production, or antibiotic resistance. LS4 was investigated for its suitability for technological processes (pH, temperature and NaCl treatment). LS4 exhibited strong antimicrobial activity caused by the production of organic acids and bacteriocin, and it produced an exopolysaccharide composed of glucose with a molecular weight of 3.7 × 10 Da. Furthermore, LS4 improved the organoleptic qualities of kimchi juice. Our results indicate that LS4 could be used as a functional starter culture for food (vegetable or fruit) fermentation at low temperatures.