响应面法优化粪肠球菌包被发酵培养基

本研究旨在优化粪肠球菌包被发酵培养基,以获得高密度包被粪肠球菌。以包被培养活菌含量为检测指标,采用Plackett-Burman(PB)试验分析培养基中对粪肠球菌发酵影响最重要的主要因素,结合响应面法(RSM)对主要因素进行了优化,并研究了最优条件下包被培养的粪肠球菌冻干粉的稳定性。结果表明,最优包被发酵培养基配方为:葡萄糖4.93%、蛋白胨 1%、牛肉膏 0.8%、酵母粉 0.6%、柠檬酸铵 0.3%、K₂HPO₄·7H₂O 0.2%、MgSO₄·7H₂O 0.06%、MnSO₄·H₂O 0.045%、NaAc·3H₂O 0.6%、吐温80 0.1%、海藻酸钠 1.87%、纳米碳酸钙 3.65%。在此条件下,粪肠球菌包被活菌数达6.83×10⁹ CFU/mL,与预测值误差仅4.12%。贮存稳定性试验表明,制备成的冻干粉在37 ℃条件下贮存90 d后仍保留80%以上的存活率,说明包被培养粪肠球菌冻干粉具有较高的稳定性。

Optimization of Encapsulated Fermentation Medium for Enterococcus faecalis by Response Surface Method

The aim of this study was to obtain high-density encapsulated Enterococcus faecalis by optimization of encapsulated fermentation medium.In this study,the viable encapsulated bacteria concentration was used as the evaluation index,Plackett-Burman(PB)test was used to analyze the main factors of encapsulated fermentation medium. Then,response surface method(RSM)was used to optimize the main factors. The stability of freeze-dried powder of Enterococcus faecalis cultured under the optimal conditions was studied. Results showed that,the optimal fermentation medium was designed as follows:Glucose 4.93%,peptone 1%,beef extract 0.8%,yeast 0.6%,ammonium citrate 0.3%,K₂HPO₄·7H₂O 0.2%,MgSO₄·7H₂O 0.06%,MnSO₄·H₂O 0.045%,NaAc·3H₂O 0.6%,Tween 80 0.1%,sodium alginate 1.87%,and nanometer calcium carbonate 3.65%.Under these conditions,the viable encapsulated Enterococcus faecalis reached 6.83×109 CFU/mL,with an error of only 4.12% compared with the predicted value. Storage stability test showed that the prepared freeze-dried powder still retained more than 80% survival rate after 90 d storage at 37 ℃,indicating that the freeze-dried powder of encapsulated cultured Enterococcus faecalis had high stability.