Screening and identification of lactic acid bacteria strains with high acid-producing from traditional fermented yak yogurt

¹ College of Food Science, Southwest University, 400715, Chongqing, China
² Chongqing Engineering Research Center of Regional Food, 400715, Chongqing, China
³ Chongqing Collaborative Innovation Center for Functional Food, Chongqing University of Education, 400067, Chongqing, China
⁴ Department of Biological and Chemical Engineering, Chongqing University of Education, 400067, Chongqing, China
⁵ Institute of Qinghai-Tibetan Plateau, Southwest University for Nationalities, 610041, Chengdu, China
⁶ College of Life Science and Technology, Southwest University for Nationalities, 610041, Chengdu, China

^a Corresponding author: birget@swu.edu.cn
^# Co-first author

Abstract

A total of 57 strains of lactic acid bacteria (LAB) were isolated and purified from traditional fermented Yak Yogurt in Hongyuan-Sichuan and Yangbajing-Tibet. The strains with high acid-produced were screened by soluble calcium circle and titratable acidity determination. The five strains, 7-1, 22-1, 28-1, 34-1 and 62-1, possessed the high acid-producing and the value of titratable acidity is 196.2, 191.1, 192.2, 194.8 and 200.2 T respectively. Based on 16S rDNA sequence analysis, 22-1 was identified as Lactococcus lactis subsp. lactis, 28-1 as Lactobacillus casei, 34-1 as Lactobacillus fermentium, 7-1 and 62-1 as Enterococcus durans. This study could provide the evidence for researching fermentation strains to improve yogurt quality.