Acid Tolerance of Lactobacillus brevis Isolated from Kimchi

We isolated wild lactic acid bacteria from kimchi and identified as Lactobacillus brevis by using API 50 CHL Kit, some morphological and physiological tests. In order to evaluate the acid tolerance of Lactobacillus brevis, its survivals rate, glycolysis assay, membrane permeability, and pH profiles of were also determined. When Lactobacillus brevis were incubated in Lactobacilli MRS broth adjusted to various levels of pH for 2 hours, the decreases in its population at pH 4.0 and 3.0 were about 2.61 log cycles/mL and 5.89 log cycles/mL, respectively, but there was no decrease at pH 6.0 and 5.0. Glycolysis by Lactobacillus brevis had optimal pH about 6.5 and glucose degradation was reduced by 50% at a pH of 5.2. release from Lactobacillus brevis cells in medium with pHs of 4.0 and 3.0 was 24.3 and 71.2% of totals, respectively. The of Lactobacillus brevis showed a maximal activity between pH values of approximately 6.5 to 7.0.