两歧双歧杆菌耐氧耐酸耐胆盐优良菌株的选育

Screening of oxygen,acid and bile salt tolerant Bifidobacterium bifidum strains

通过反复驯化的培养方法将两歧双歧杆菌驯化成耐氧耐酸耐胆盐的优良菌株。实验结果表明,在牛乳培养基中耐氧驯化后的双歧杆菌的增殖比例为41000%,而原始菌的增殖比例仅为8233%,且前者的凝乳时间为后者的2/3;经过耐酸驯化的菌株在低pH值条件下的产酸性能也大为提高,且耐酸性明显优于未经驯化的菌株;胆盐驯化的菌株经胆盐浓度为0.5%的培养后也有较高的活菌数,其对胆盐的忍耐力明显增强。

The Bifidobacterium bifidum were domesticated with the traditional cultivation method. In the oxygen-tolerant domestication, we increased the oxygen pressure to domensticate the Bifidobacterium bifidum. And in the acid-tolerant domestication, Bifidobacterium bifidum were domesticated by lowering the pH of the liquid medium. The results show that the capability of the domesticated Bifidobacterium bifidum is superior to the original strains. In the milk medium, the growth rate for the domesticated strains is 41000%, and that for the original strains is only 8233%. The production of the acid is more than the original strains, and the milk-coagulating time has been shortened to 2/3. In the bile salt-tolerant domestication, while the bile salts concentration is 0.5%, the concentration of the domesticated one can also reach to as high as 1×106 cfu/ml.