A New Method Of Quantitative Analysis On Bifidobacteria

As the most important probiotics in the human and warm-blood animals, bifidobacteria play a various role on the host in the health promotion. At present, market has been occupied by the mixture of microbial inoculum with bifidobacteria and lactic acid bacteria. However, a relatively accurate detection method is needed .This paper aimed to establish a new bifidobacteria quantitative analysis technique. At first a cultivated system for bifidobacteria is established. The results of cultivation demonstrated BBL agar medium and TPY liquid medium as the medium of bifidobacteria bifidum have better effects on the cultivation of bifidobacteria bifidum.Then optimum conditions of determining Bifidobacteria genus-specific enzyme activity(F6PPK) were carried out. First, we modified the way to establish control reaction tube in F6PPK determination in the original literature (called Scardovi method). Then we optimized the cultivation time of Bifidobacteria bifidum, cell disruption method, substrate concentration, colorimetric wavelength, enzymic reaction temperature and time. The results showed that after cultivated for 18 h, the cells of Bifidobacteria could be harvested and be prepared for crude enzyme through sonication disruption, and to measure F6PPK activity, 4 % substrate concentration, 40℃and 30 min of reaction temperature and time, 500 nm wavelength were chosed, and the F6PPK activity data obtained under these conditions were proved to be more reliable.We harvested a series culture containing different number of bacteria due to different cultivation time. With anaerobic box method the number of bifidobacteria was measured and F6PPK activity was detected with optimized method. Then, the work curve reflecting the relationship of the number of Bifidobacterium bifidum to F6PPK activity and that of Bifidobacterium longum to F6PPK activity were established, respectively. Further more, the curves were verified using the market products. The results of the plate counting were consistent with that of by the work curves. In a word, this method is proved authenticity and reliability for the quantification of bifidobacteria in bifidobacteria mixture products .