水牛乳中高产胞外多糖乳酸菌的筛选与鉴定

从生水牛乳中筛选出两株高产胞外多糖（EPS）的乳酸菌株LB2、LB7，经MRS肉汤培养基发酵后，菌液中的胞外多糖（EPS）产量分别达135 mg/L、148 mg/L，通过形态学、生理生化特征、API细菌鉴定系统、16S rRNA序列分析，鉴定出菌株LB2为植物乳杆菌（Lactobacillus plantarum），LB7为类肠膜魏斯氏菌（Weissella paramesenteroides）。将其应用到水牛乳酸奶的发酵中，结果表明，植物乳杆菌LB2和类肠膜魏斯氏菌LB7均可用来发酵水牛乳酸奶，且能有效增加酸奶的黏度和胞外多糖产量，其黏度和EPS产量分别为4 050 mPa·s和149 mg/L。

Screening and identification of lactic acid bacteria with high yield extracellular polysaccharides from buffalo milk

Two lactic acid bacteria strains LB2 and LB7 with high yield extracellular polysaccharides (EPS) were screened from raw buffalo milk.After fermentation in MRS medium, the EPS production in fermentation broth was up to 135 mg/L and 148 mg/L, respectively. Through strains morphological, physiological and biochemical characteristics identification, API bacteria identification system, 16S rRNA sequence analysis, the strain LB2 was identified as Lactobacillus plantarum, LB7 was identified as Weissella paramesenteroides. The strains were applied to the buffalo milk fermentation, the results showed that LB2 and LB7 were available to ferment milk yogurt, and can effectively increase the viscosity of yogurt and extracellular polysaccharide production. The viscosity and EPS yield of the yogurt was 4 050 mPa·s and 149 mg/L, respectively.