Antibacterial Properties Of Propionin And Optimization Of Fermentation Process For High Producing Strain

In this paper, Propionibacterium freudenreichii CS01 was used as the parent strain, influencing factors of the antibacterial properties were studied and the medium and cultural conditions of Propionibacterium freudenreichii CS01 were optimized.Propionibacterium freudenreichii CS01 was inoculated into fermentation medium, incubated 9 days by submerged cultivation, the broth was centrifuged (4℃,8000 r/min,5 min), the supernatant was the metabolite of Propionibacterium freudenreichii CS01. Excluded the Interference of acidum, the Metabolin of Propionibacterium freudenreichii CS01 was determined to be protein or peptide by ammonium sulfate precipitation and enzymic hydrolysis, named propionin; The antimicrobial characteristic against Staphyloccocus aureus were studied, the optimal conditions were:the concentration of indieator strain 107 cfu/mL, the loading quantity in oxford plate 200μL, agar concentration 1 g/L, culture temperature 37℃, culture time 12 h, and the inhibitory activity can be improved by pre-diffusion and afterextension at 4℃. Under the optimal condition, the diameter of inhibition zone was 19.8mm.The medium and cultural conditions of Propionibacterium freudenreichii CS01 have been optimized by shake flask (100mL).The original medium and cultural conditio:glucose 20 g/L, YE 10 g/L, KH2PO41 g/L, MgSO40.2 g/L, Tween801g/L, inoculum size 4%, initial pH 7.0, culture temperature 30℃, submerged fermentation time 9d.The optimal medium for Propionibacterium freudenreichii CS01 which was determined by single factor experiment:glucose was the optimal carbon source, YE was the optimal nitrogen source, tween 80 was the growth factor, the inoculum size was 5%, pH was 6.5, cultural Temp was 30℃; cultural Time was 9 d. Then three statistically significant parameters including glucose, tween80, pH were identified by Plackett-Burman design. The optimal levels of three variables were defined by central composite design and Response surface method (RSM):glucose 23.2 g/L, tween801 g/L, pH 7.0. The last optimal medium composition was glucose 23.2 g/L, YE 10 g/L, KH2PO41 g/L, MgSO40.2 g/L, Tween801 g/L, pH7.0. The optimal fermentation condition of Propionibacterium CS01 was:culture temperature 30℃, initial pH 7.0, inoculum age 70 h, inoculum size 5%, submerged fermentation time 9d. The diameter of inhibition zone was 24.76 mm. The course of fermentation was studied under the optimal condition and medium. The results were: 0-3 d, thallus was upgraded fastly, sugar was resumed with the growth of biomas, pH was descented rapidly; 3-9 d, thallus was on stationary phase, sugar was descented rapidly, pH was equability, propionin was accumulated, and the yield of propionin achieved the axlmum when the ninth-day.