屎肠球菌和枯草芽孢杆菌混合培养条件的优化

Study on Mixed Culture of Enterococcus faecium and Bacillus subtilis

以屎肠球菌和枯草芽孢杆菌为研究对象,以MRS培养基为基础培养基,采用单因素试验、Box-Behnken实验设计对屎肠球菌和枯草芽孢杆菌的混合培养进行优化。结果表明:初始p H、装液量和氮源对活菌数影响显著。最优条件为:初始p H 6.5、装液量50/500 m L、氮源用量35 g/L、接种比1∶12、转速180 r/min,在此条件下活菌数达到6.99×1010 CFU/m L,比优化前提高了5倍,屎肠球菌菌株和枯草芽孢杆菌菌株的活菌数分别达到4.58×1010 CFU/m L和2.41×1010CFU/m L。

In order to investigate the effect of Enterococcus faecium and Bacillus subtilis mixed culture on their biomass,MRS medium,single factor experiment,Box-Behnken Design were adopted to optimize the mixed culture. Results showed that medium initial p H,liquid volume and nitrogen source had significant effects on the viable counts of the strains. The optimal culture conditions were as follows：initial medium p H 6.5,50 m L liquid medium in 500 m L flask with 180 rpm in shake,35 g/L of nitrogen source,the inoculation of Enterococcus faecium and Bacillus subtilis at a ratio of 1 ∶12. Under this conditions,the total viable counts reached to 6.99 ×1010CFU/m L,with 4.58 ×1010CFU/m L of Enterococcus faecium and 2.41 ×1010CFU/m L of Bacillus subtilis,which was five times higher than that of before optimization.