猪源屎肠球菌WEI-9的高密度培养

High density cultivation of Enterococcus faecium WEI-9 isolated from swine

目的对分离自健康仔猪肠道的屎肠球菌(Enterococcus faecium)WEI-9的高密度发酵培养基进行响应面优化,为菌株WEI-9的工业化生产奠定基础。方法首先采用单因素试验确定最适高密度发酵培养基的碳源和氮源,随后采用Plackett-Burman设计筛选出影响菌株WEI-9发酵活菌数的显著因素,利用最陡爬坡试验得出显著因素逼近最大活菌数产量的响应区域,最后应用Box-Behnken设计和响应面分析法确定显著影响因子的最佳浓度。结果优化后的最适高密度发酵培养基成分和配比为:乳清粉21.34 g/L,蛋白胨21.94 g/L,Na AC·3H2O 5 g/L,柠檬酸铵2 g/L,K2HPO4·3H2O 2 g/L,Mg SO4·7H2O 0.2 g/L,Mn SO4·H2O 0.05 g/L,吐温-80 1 g/L,发酵液最高活菌数达到1.6×109CFU/m L,是相同条件下MRS培养基中活菌数的1.98倍。结论本研究实现了猪源屎肠球菌(Enterococcus faecium)WEI-9的高密度培养。

Objective To optimize the medium for high cell density fermentation of Enterococcus faecium WEI-9 isolated from the intestinal tract of a healthy 60-day-old piglet,in order to lay a foundation for industrial production of high quality probiotics. Methods Firstly,uni-factor experiments were conducted to determine the optimum carbon sources and nitrogen sources. Secondly,Plackett-Burman design was applied to screen the significant factors which enhance the production of viable Enterococcus faecium WEI-9,and the Max-min hill climbing test was utilized to investigate the optimal region for operability. Finally,these significant factors were optimized with response surface Box-Behnken method. Results The optimal medium formulation was 21. 34 g / L of dried whey powder,21. 94 g / L of peptone,5 g / L of Na AC·3H2O,2 g / L of ammonium citrate,2 g / L of K2HPO4·3H2O,0. 2 g / L of Mg SO4·7H2O,0. 05 g / L of Mn SO4·H2O,and 1 g / L of Tween-80. The improved medium produced a viable cell count up to 1. 6 × 109 CFU / m L under flask cultivation conditions,1. 98 times of the count in MRS medium. Conclusion The high density cultivation of Enterococcus faecium WEI-9 has been achieved actually.