Study on Mixed Culture of Enterococcus faecium and Bacillus subtilis

Abstract:

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 pH，liquid volume and nitrogen source had significant effects on the viable counts of the strains. The optimal culture conditions were as follows：initial medium pH 6.5，50 mL liquid medium in 500 mL 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 6.99×1010 CFU/mL，with 4.58×1010 CFU/mL of Enterococcus faecium and 2.41×1010 CFU/mL of Bacillus subtilis，which was five times higher than that of before optimization.