Optimization of Protective Agent Formulation for Soybean Rhizobium Strain HW-05 by Response Surface Methodology

摘要

[Objective] T his study aimed to investigate the protective effects of proteins,salts,sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method]Different types,combinations,ratios and concentrations of protective agents were designed. Under simulated conditions,the optimal protective agent formulation was screened for improving the survival rate and survival time of soybean rhizobium strain HW-05. The optimal combination of significant factors was determined by Box-Behnken central composite design. [Result] T hree significant factors affecting effective number of viable cells were screened,including peptone,xanthan gum and Na Cl. The final concentration of each compound was optimized: 0. 13% peptone,0. 011% xanthan gum,0. 30%Na Cl. [Conclusion] After addition of protective agent and preservation at room temperature for six months,effective number of viable cells of soybean rhizobium strain HW-05 reached 3.185 × 10~8 CFU / ml. The survival rate of HW-05 cells was improved by more than 25% compared with the control group(2.458×10~8 CFU / ml).