响应面法对漆斑菌液体发酵产胆红素氧化酶条件的优化

Optimizing Conditions of Producing Bilirubin Oxidase by Myrothecium sp. IMER1Using Response Surface Methodology

对漆斑菌(Myrothecium sp.IMER1)菌株液体发酵产胆红素氧化酶的条件进行了优化。采用单因素试验筛选出最适碳源为葡萄糖,氮源为硝酸铵,p H为7,温度为28℃和最有效促进产酶的金属离子为Cu2+。在此基础上,利用Plackett-Burman设计对影响产酶因素的效应进行评价,筛选出具有显著影响的3个因素葡萄糖、p H和温度。用最陡爬坡路径逼近最大产酶区域后,利用响应面中心组合设计对显著因素进行优化,得出p H、温度和葡萄糖分别为5.7、28℃、8 g/L时,优化后液体发酵液中胆红素氧化酶活力提高到0.627 U/m L,比未优化前的酶活力0.214 U/m L提高了近2倍,结果表明单因素与响应面结合法可优化菌株IMER1液体发酵产胆红素氧化酶的条件。

The fermentation conditions of producing bilirubin oxidase （BOX） by Myrothecium sp. IMER1 were optimized. The optimal carbon source glucose, nitrogen source NH4NO3, pH 7, 28 ℃ and metal ion Cu^2＋ were screened with single factorial experiments. Plackett-Burman design was used to evaluate the effects of six factors related to BOX production. Three statistically significant factors including glucose, pH and temperature were selected. The path of steepest ascent was used to approach the optimal region of BOX production subsequently. The optimal combined concentration for maximum enzyme activity was further optimized by response surface methodology and determined as follows： 5.7,28 ℃, 8 g/L. The maximum enzyme activity was 0.627 U/mL. The optimization of culture conditions of IMER1 led to about 2 fold increase in BOX enzyme activity compared with initial result 0.214 U/mL, indicating that single factor in combination with response surface methodology was an effective method for optimizing BOX enzyme activity conditions by Myrothecium sp. IMER1.