Physiological Characteristics and GABA Production of Lactobacillus plantarum K255 Isolated from Kimchi

Abstract

As a major inhibitory neurotransmitter of the central nervous system in animals, <TEX>${\gamma}$</TEX>-aminobutyric acid (GABA) has several physiological functions, such as anti-hypertensive, diuretic, tranquilizer and anti-stress effects in human. In order to determine strains with high GABA producing ability and glutamate decarboxylase (GAD) activity, 273 bacteria were isolated from various types of Kimchi. Strain K255 contained <TEX>$386.37{\mu}g/mL$</TEX> of GABA in MRS broth containing 1% MSG, <TEX>$600.63{\mu}g/mL$</TEX> of GABA in MRS broth containing 2% MSG and <TEX>$821.24{\mu}g/mL$</TEX> of GABA in MRS broth containing 3% MSG. It showed that K255 had the highest GABA production ability compared to other commercial lactic acid bacteria. K255 was identified as Lactobacillus plantarum based on its API carbohydrate fermentation pattern and 16S rDNA sequence. K255 was investigated for its physiological characteristics. The optimum growth temperature of K255 was <TEX>$37^{\circ}C$</TEX>and cultures took 13 h to reach the pH 4.4. K255 showed more sensitive to bacitracin in a comparison of fifteen different antibiotics, and showed most resistance to kanamycin and vancomycin. Moreover, it was comparatively tolerant to bile juice and acid and displayed resistance to Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, with rates of 30.8%, 29.7%, and 23.4% respectively. These results demonstrate that K255 could be an excellent strain for the production of functional products.