响应面法优化大肠埃希菌生产PCV2 Cap蛋白的诱导条件
Optimization of Induction Conditions for Producing PCV2 Cap by Response Surface Methodology in Escherichia coli

为提高重组大肠埃希菌发酵生产PCV2 Cap蛋白的产量，优化宿主菌的表达条件。在单因素试验基础上，以接种量、诱导时间和诱导温度为自变量，目的蛋白产量为响应值，根据响应面法的Box-Behnken 中心组合设计原理，研究各自变量及其交互作用对PCV2 Cap蛋白产量的影响，利用Design-Expert软件和响应面分析相结合的方法对诱导条件进行优化。结果表明：发酵的最佳诱导条件为接种量φ=2.21%，诱导时间21.76 h，诱导温度 18.2 ℃。在该诱导条件下，摇瓶中获得最高蛋白产量为318.50 mg/L，发酵罐获得最高蛋白产量为1 200.00 mg/L。采用响应面分析方法能够有效地提高目的蛋白的表达量。
To improve the expression level of porcine circovirus type 2 (PCV2) Cap protein in recombinant E.coli,prokaryotic expression conditions were optimized. An optimized process using response surface methodology was conducted in this study on the basis of single factor screening experiments. Inoculation dose,induction time and induction temperature were served as independent variables,and the target protein production was served as the response value. Box-Behnken design method was used to study the effects of each independent variable and their interactions on target protein yield. Design-Expert software and response surface analysis were combined to optimize and confirm the best induction conditions. The results showed that the optimal induction conditions were determined as follows: inoculation dose φ=2.21%,induction time 21.76 h and induction temperature 18.2 ℃.Under the optimal induction condition,the highest target protein yield was achieved by 318.50 mg/L in shake flask and 1 200.00 mg/L in 3-liter fermenter respectively. In conclusion,RSA is an effective method to improve the expression of recombinant protein.