Characterization Of Probiotic Properties And Optimization Of Solid-state Fermentation Process For High-yield Spore Production Of Bacillus Subtilis CCAM 080032

A series of security issues such as drug resistance,residual toxicity caused by antibiotics abuse have attracted more and more attention. To find a safe substitute is imperative. As an alternative of the antibiotics, Bacillus preparations can not only inhibit the growth of pathogenic bacteria and improve animal production performance, but also be tolerant to adverse environment. So Bacillus preparations have broad application prospects.Bacillus subtilis CCAM 080032 used in this study was found to be tolerant to adverse environment and achieve high level enzyme production we can evaluate its potential as a probiotic. Then optimal solid-state fermentation medium and conditions for high-yield spore production of Bacillus subtilis CCAM 080032 were ascertained. The results in detail were as follows:1. B. subtilis can still live and reproduce in hyperisotonic condition with 14% NaCl; further research indicated that the strain possessed tolerance to the artificial gastric juice, artificial intestinal juice and bile. At last, this stain possessed some heat resistance to some extent; the survival rate of germ would maintain 90% when it was treated below 80℃.2. The neutral protease activity,alkali protease activity,xylanase activity,cellulase activity of Bacillus subtilis CCAM 080032 solid-state fermentation production were 107.70 U/g,888.52 U/g,20.28 U/g,8.99 U/g. The existence of these three enzymes will help animals with digestion and absorption of nutrients, promote animal growth, reduce feed costs and improve breeding efficiency.3. The optimal medium was composed of rice straw powder 200 g and wheat bran 800 g supplemented with glucose 50 g, tryptone 20 g, NH4NO315 g, KH2PO4 10 g and H2O 1500 g; The optimal conditions:fermentation time 48 h, fermentation temperature 37℃, inoculum concentration 5%, inoculum age 17 h. Under these optimal solid-state fermentation medium and conditions, the maximum spore production was improved to 7.90×1010CFU/g. 4. Set the initial temperature of the fermentation process to 37℃, control the maximum temperature of the fermentation process lower than 45℃, best to keep 37℃, and churn the solid-state fermentation medium regularly, then a high spore production will be obtained. This conclusion is important for practical production of Bacillus subtilis CCAM 080032.5. The spore production could achieve 1.06×1010 CFU/g,1.85×1010 CFU/g,11.09×10 CFU/g respectively by application of a new fermentation equipment,Ventilating Fermentation bioreactor and shallow pan. Shallow pan fermentation has the absolute advantage for spore production, the new fermentation equipment needs to be improved.