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Isolation and identification of lactic acid bacteria (Lactobacillus plantarum YS2) from yak yogurt and its probiotic properties

Yu Qian, Xingyao Long, Yanni Pan, Guijie Li, Xin Zhao

In this study, a lactic acid bacterium was isolated and identified from Yushu in China, and its probiotic properties were determined. After cultured in MRS medium, a bacterium was identified as lactic acid bacteria by staining and microscopic observation. And the lactic acid bacteria was further identified as Lactobacillus plantarum by physiological and biochemical tests. The lactic acid bacterium was also identified as Lactobacillus plantarum by 16sDNA determination, and the lactic acid bacteria was named Lactobacillus plantarum YS2 (LP-YS2). The acid resistant activity of LP-YS2 (68.05%) were higher than that of Lactobacillus bulgaricus (LB, 30.35%). LP-YS2 also showed the higher bile salt resistant activities (19.85%, 15.01% and 8.35%) than those of LB (3.08%, 1.87% and 1.44%) in 0.3%, 0.5% and 1.0% bile salt. The hydrophobicity results also showed that LP-YS2 (72.35%) had the higher hydrophobicity than LB (45.67%). LP-YS2 had the good values in food and bio pharmaceutical development.