The Screening Of Acid-Resistant Bifidobacterium From Human Resouce And The Evaluation Of The Capacity

Bifidobacterium is a probiotic with a variety of benefits to the host. Probitic products have also been studied and applied much more widely. The probiotics must be alive when they get to the intestinal tract otherwise they can not be effective for our health. However, the Bifidobacterium is very sensitive to the acid environment. So it is very important to screen better acid-resistant strains from human beings for the production of the probiotics. Now the way to increase the acid-resistance of the stains is to expose them to the sublethal acid stress for a short time, but it is not useful to the Bifidobacterium .So we have to try out to find a new method to increase the strain's acid-resistance.We exposed the Bifidobacterium to the lethal acid environment for a long time and screened 22 Bifidobacterium. We evaluated their capacity of acid-resistant by researching the survival rate after exposing them to adverse environment and selected the best two strains. After going down to the 20th generations, we evaluated their acid-resistance again and made sure that their capacity of aid-resistant could be passed down from generation to generation. Then we evaluated other capacity of the strains including heat-resistance, oxidation resistance, bile salts resistance and the survival rate in the gastrointestinal environment. After all these evaluations, we selected Bifidobacterium longum SQS7-31 as a potential stain which could be applied in the production.