纳豆芽孢杆菌液体发酵条件的优化研究

Optimization of Liquid Fermentation of Bacillus natto

采用单因素试验和正交实验对筛选出的1株纳豆芽孢杆菌(Bacillus natto)的液体发酵培养基和发酵工艺条件进行了优化。确定了最佳的培养基配方为蔗糖2%、大豆蛋白胨1%、硫酸铵0.5%、Na2HPO40.1%、NaH2PO40.1%、CaCl20.02%、MgSO40.1%;最适发酵条件为发酵温度37℃,初始pH值7.0,最适接种量4%、装液量100mL/500mL、转速200r/min。进行了50L发酵罐放大培养,10h达到生长高峰期,最适放罐时间为12h左右,此时所获得的菌体数量约为6.0×1010cfu/mL。

The liquid fermentation medium and conditions of Bacillus natto were optimized by single factor experiments and orthogonal experiments. The opfmal medium is found using sucrose 2%, soya peptone 1%, （NH4）2SO4 0.5%, Na2I-IPO40.1%, NaH2PO40.1%, CaCI2 0.02%, and MgSO40.05%. The optimal fermentation conditions are as follows： temperature 37 ~C, initial pH7.0, inoculation amount 4%, liquid volume 100mL/500mL, and shaking speed 200r/min. In scale-up culture in 50 L fermenter, the highest growth rate is achieved at 10h. The optimum cultivating time is about 12h, with which the obtained bacterium amount was up to 6.0×10^10cfu/mL in fermentation liquid.