Studies On High-density Cultivation And Freeze-drying Process Of Bifidaobacteria Adolescentis

Bifldobacterium is a kind of important inhabitant bacteria in intestinal tracts of human. It has a lot of biological function such as preventing and curing intestine infection, modulation of the immunological response and antitumour. It has direct beneficial effects on intestinal health. Bifidobacterium is widely used on foods and microecological medicines. However, Bifldobacterium is a kind of strict anaerobic bacteria and needs rigorous culture condition. It is hard to get high viable count during fermentation which restricts the exploiture and application of Bifidobacteria production. At this research, high density cells was got via fed-batch cultivation and the freeze-drying technologic condition was screened out. The main contents and concludes were as follows:1 Higher living cells amount was got via Bifidobacteria adolescentis fed-batch high density culture.On the base of studying Bifidobacteria adolescentis batch culture, fermentation broth pH value was modulated by adding lye and glucose was added into fermentation broth in order to eliminate the restrain of carbon source scarcity which prolonged logarithmic phase and increased max viable count. Cell concentration came to the maximum and Bifidobactetia adolescentis high-density culture came true. Logarithmic phase of high-density culture prolonged 8 hours from 6 to 14. Max viable count increased from 3.9×10~8cfu/mL to 4.6×10~9cfu/mL, more than 10.8 times.2 The technologic condition of Bifidobacteria adolescentis fermenter high-density culture was ascertained.The technologic condition of Bifidobacteria fermenter high-density culture was ascertained on the base of studying fermenter batch culture and bottle fed-batch high-density culture. The Technologic condition was as follow. Medium in 10 liter fermenter after sterilization was 8 liter. The original pH value was 7.0. Nitrogen was used to keep the fermenter pressure and pressure value was 0.1 MPa. The inoculum size was 5% and cultural temperature was 37°C. Churnning rate was 80r/min. Lye was added into fermenter when pH value dropped to 5.76 after 6 hours' cultivation. The pH value was kept at 6. Glucose was added into fermenter when reducing glucose concentration drop to 4g/L after 10 hours' cultivation. The glucose concentration was kept at 4-6g/L. 6-20 hours was Bifidobacteria's logarithmic phase. Stopping cultivation at the end of logarithmic phase when the OD...