产L-乳酸之乳杆菌的筛选

本研究通过平板划线法及乳酸发酵实验,从干酪及酸菜样品中分离筛选出二株具有较强产L-乳酸能力的乳杆菌。经糖发酵、生长温度、精氨酸发酵产氨、产硫化氢试验及细胞壁中二氨基庚二酸(DAP)成分分析,确认为干酪乳杆菌干酪亚种和干酪乳杆菌鼠李糖亚种。它们在葡萄糖85g/L,乳糖35g/L,酵母膏5g/L,蛋白胨10g/L,NaCl1.3g/L,K2HPO41.5g/L,MgSO4·7H2O0.33g/L,MnSO40.05g/L的培养基中,于37℃下培养48h,产L-乳酸的量分别达到56.50g/L和50.80g/L。

Screening of L-Lactic Acid Yielding Lactobacillus Strains

Two Lactobacillus strains which had higher L-lactic acid yielding have been isolated and purified from the mixed cheese samples and fermented vegetable, and were identified by API bacterial identification system as Lactobacillus casei subsp. case and Lactobacillus casei subsp. rhamnosus. After fermentation in the culture consisted of following composition (g/L): glucose 85, lactose 45, yeastrel 5, peptone 10, NaCl 1.3, K2HPO4 1.5, MgSO4·7H2O 0.33, MnSO4 0.05 at 37 ℃ for 48 h, the yield of L-lactic acid are 56.50 g/L and 50.80 g/L, respectively.