新疆传统酸奶中产胞外多糖乳酸菌的筛选与鉴定

试验选择6种新疆地区不同传统酸奶,通过平板涂布、划线分离、革兰染色、接触酶试验和凝乳试验鉴定后得到4株乳酸菌,分别命名为L1、L2、L3、L4。通过PCR鉴定16S rDNA序列,证明L1、L2株为干酪乳杆菌（Lactobacillus casei）,L3、L4株为植物乳杆菌（Lactobacillus plantarum）;4株乳酸菌L1、L2、L3、L4的产胞外多糖含量分别为176、248、205、294 mg/L;L4株产胞外多糖量最高,L1株产量最低。研究丰富了产胞外多糖乳酸菌发酵剂的种类。

Screening and Identification of Exopolysaccharides Producing Lactic Acid Bacteria from Traditional Xinjiang Yoghurt

Four strains of lactic acid bacteria, designated as L1, L2, L3 and L4 respectively, were isolated and preliminarily identified from six types of traditional Xinjiang yoghurt by Gram′s staining, contact enzyme test and rennet test. The 16S rDNA sequence analysis results demonstrated that the strains of L1 and L2 were Lactobacillus casei, and the strains of L3 and L4 were Lactobacillus plantarum; the content of exopolysaccharides produced by the lactic acid bacteria strains of L1, L2, L3 and L4 was 176 mg/L, 248 mg/L, 205 mg/L and 294 mg/L respectively, indicating that the highest and lowest exopolysaccharides was obtained in the strains of L4 and L1, respectively. Our study enriched the available types of exopolysaccharides producing fermentation starter of lactic acid bacteria.