产脂肪酶粘质沙雷氏菌发酵产酶条件的优化

目的：通过对产脂肪酶粘质沙雷氏菌发酵条件的优化,使其酶活力得到大幅度提高。方法：用响应面法对产脂肪酶粘质沙雷氏菌的发酵产酶培养条件进行了优化。首先通过逐因子实验考察了该菌株产酶所需的最适碳源和氮源,在此基础上通过Plackett-burman法设计实验,考察了几种因素对产酶影响的大小,然后用最陡爬坡实验逼近以上几种因子的最大响应区域后,采用Box-Behnken设计25组实验,并利用Design-Expert对实验结果进行二次回归分析。结果：对产酶具有显著效应的4个因素为：蛋白胨、CaCl2、吐温、大豆油。实验优化到最佳的产酶条件为：糊精1%,蛋白胨0.7%、CaCl20.3%、吐温-80 1.68%、大豆油1.81%、K2HPO40.05%、MgSO40.05%、FeSO40.1%。结论：优化后发酵液上清的脂肪酶活力可达97.52U/ml,比优化前提高了10倍。

Optimization of Fermentation Conditions for Producing Lipase by Serratia marcescens

Objective: Fermentation Conditions for producing lipase by Serratia marcescens were optimized in order that the lipase activity was increased substantially.Method: Lipase production condition of Serratia marcescens was fleetly optimized by Response Surface Methodology(RSM).Firstly,The optimum carbon and nitrogen for Serratia marcescens were obtained through seriatim-factorial experiment on this basis,a Plackett-Burman design was used to evaluate the effect of different factor on the lipase production.Result:Four factors had prominent effect on lipase production were picked out,which were peptone,CaCl_2,Tween 80 and soybean oil.And then steepest ascent procedures were employed to define optimal response region for these four factors.Finally,Box-Behnken was utilized to design 25 groups of experiments.Quadratic regression design was employed to analyze the results of experiments by Design-expert software.Conclusion:The optimal culture medium was composed of 0.69% tryptone,0.3% CaCl_2,tween 80 1.87%,soybean oil 1%,K_2HPO_4,1%,MgSO_4 0.05%,FeSO_4 0.1%,the yield of enzyme activity achieved 97.52U/ml,the yield of lipase is increased by 10 times than pre-optimization.