新疆紫花苜蓿根瘤菌XGL026发酵条件的响应面法优化筛选

在摇瓶培养条件下对分离获得的抗逆、高效新疆紫花苜蓿中华根瘤菌（Sinorhizobium sp.） XGL026菌株的发酵条件进行优化。依据单因素试验结果，采用Plackett-Burman设计对菌体生长的影响因素进行效应评价，筛选出麦芽糖浓度、酵母膏浓度及初始pH是显著影响菌株生长的主要因子。响应面法优化获得根瘤菌XGL026的最佳培养基为：麦芽糖27.20 g·L^-1，酵母膏10.54 g·L^-1，K₂HPO₄0.8 g·L^-1，MgSO₄·7H₂O 0.2 g·L^-1，NaCl 0.1 g·L^-1，初始pH 6.98。在转速150 r·min^-1， 28℃条件下摇瓶培养24 h，活菌数可达3.47×10¹² cfu·mL^-1。通过3次重复的发酵试验验证，与预测值相对误差为1.17%，表明模型拟合效果良好。

Optimization of Shake Flask-fermentation Conditions of Alfalfa Rhizobium XGL026 From Xinjiang Using Response Surface Method

Optimization of fermentation conditions of a stress resistant and nodulation efficient Xinjiang Alfalfa Rhizobium strain XGL026 was performed under a shake-flask culture condition. Based on the results of single factor test, we evaluated the main factors which affected XGL026 growth. The results showed that Maltose concentration, yeast concentration and initial pH were important factors that affected growth of XGL026. The optimum medium formulas of XGL026 by Response Surface method was:Maltose 27.20 g·L^-1,Yeast 10.54 g·L^-1,K₂HPO₄0.8 g·L^-1,MgSO₄·7H₂O 0.2 g·L^-1, NaCl 0.1 g·L^-1 and initial pH 6.98. When XGL026 was cultured in the medium in a flask,shaked for 24 h under the conditions of speed 150 rpm, 28℃, the number of viable cells could reach 3.47×10¹² cfu·mL^-1. Through 3 times repeated test, the predicted relative error was 1.17%, which showed that the model fitting effect is good.