响应面法优化大肠杆菌产海藻糖合酶发酵培养基

Optimization of fermentation conditions for trehalose synthase production by Escherichia coli using response surface method

以海藻糖合酶基因工程菌E.coli BL21(p ET15b-Tre S)为研究对象,以海藻糖合酶的酶活为考察指标,对海藻糖合酶基因工程菌E.coli BL21(p ET15b-Tre S)的培养基进行优化。首先运用单因素实验对大肠杆菌(E.Coli)产海藻糖合酶进行了优化,利用Plackett-Burman进行两因素两水平设计对影响其产酶因素进行评估并筛选出具显著效应的3种因素:葡萄糖、酵母浸粉和K2HPO4。用最陡爬坡实验逼近以上三种因素的最大响应面区域后,采用Box-Behnken进行三因素三水平的设计以及响应面分析,获得最佳产海藻糖合酶的培养基。结果表明,发酵大肠杆菌的最佳培养基配方为:葡萄糖7.2g/L,酵母浸粉6.6g/L,蛋白胨10g/L,(NH4)2SO45g/L,K2HPO415.7g/L,KH2PO44g/L,Mg SO4·7H2O1.6g/L,微量元素混合液0.5m L/L。在此条件下进行产酶重复实验5次,海藻糖合酶酶活为65U/mg,比优化前提高了91.2%。

The fermentation medium composition of Trehalose synthase gene engineering bacteria Ecoli BL21 (pETl5b-TreS)were optimized for bacteriocin production.The conversion rate of trehalose synthase was used as evaluation index.Firstly,the effects of the single factors on bacterioc in production from strain E.coli BL21 ( pET15b- TreS)were examined.To obtain the best producing trehalose synthase medium,three key factors influencing the trehalose synthase production: glucose,yeast extract powder and K2HPO4, were determined by Plackett- Burman design experiment.And then response surface methods were applied.Results showed that the best culture media component for the fermentation by E.cofi were. glucose 7.2g/L, yeast extract powder 6.6g/L, peptone 10g/L, ( NH4 ) 2 SO4 5 g/L, K2 HPQ 15.Tg/L, KH2 PQ 4g/L, MgSO4·7H20 1.6g/L, mixture of microelement 0.5 mL/L. Under this conditions the enzyme activity was 65U/mg,increased 91.2%.