产天冬氨酸酶菌株大肠杆菌HY-05C发酵培养基及培养条件的优化

Culture medium and conditions optimization of L- aspartase- producing strains by Escherichia Coli HY-05C

为提高大肠杆菌HY-05C在L-天冬氨酸生产过程中的菌体浓度,进而提高单位体积培养液中L-天冬氨酸酶酶活,本文对该菌株的培养基和培养条件进行了优化。首先通过正交实验对大肠杆菌HY-05C培养基组成进行优化,确定了最佳培养基配方(g/L):富马酸铵10,玉米浆干粉8,酵母粉2,蛋白胨7,氯化钠5,磷酸二氢钾1,硫酸镁0.2。又进一步考察了对菌体浓度和酶活影响较大的因素初始p H和接种量,得到了最适p H=6.0,最佳接种量为1.0‰,在上述最佳培养基及培养条件下对大肠杆菌HY-05C的酶转化进程进行测定,优化后培养液的转化效率较初始提高150%,同时也验证了通过发酵条件优化提高单位体积的菌体浓度,提高L-天冬氨酸转化效率方法的可行性。

In order to improve the cell concentrations and L- aspartase activity durting the L- asparate production of Escherichia coli HY- 05 C,the culture medium and culture conditions were optimized. First of all,the orthogonal experiment was employed to optimize the medium compositions and the optimal fermentation medium was obtained（ g / L） ： ammonium fumarate 10,corn steep liquor powder 8,yeast powder 2,peptone 7,Na Cl 5,KH_2PO_41,Mg SO_4 0.2.Furthermore,the initial p H and inoculum size which had significant influence on bacteria concentration and enzyme activity were investigated,and the optimal p H and inoculum size were determined as 6.0 and 1‰,respectively.Finally,the enzymatic conversion process of E.coli HY-05 C was confirmed using the optimal medium and the culture conditions. Compared with the initial cultual conditons,its conversion efficiency was improved by150%. Also,it verified the feasibility that the increasing cell concentrations via the optimization of fermentation conditions could enhance the conversion efficiency of L- asparatase in E.coli HY-05 C.