响应面法优化乳酸乳球菌电转化效率研究

Optimization of Electroporation Efficiency of Lactococcus Lactis Using Response Surface Methodology

乳酸乳球菌NZ9000是乳酸菌食品级高效蛋白表达系统中使用最广泛的宿主菌株。为获得高效的电转化效率,首先采用单因素试验,对影响NZ9000电转化效率的各因素:生长阶段、甘氨酸浓度、质粒浓度、电场强度、复苏培养和复苏时间进行优化;然后利用响应面法对其中的关键因素进一步优化,确定最佳电转化条件为吸光值OD600 0.2,甘氨酸浓度8 g/L和电场强度12.5 kV/cm,电转化效率达到3.76×10~7 CFU/μg DNA,比优化前提高了250%。本研究通过优化乳酸乳球菌NZ9000感受态的制备方法,提高了电转化效率,为深入挖掘乳酸乳球菌感受态潜力奠定了基础。

Lactococcus lactis (L. Lactis) NZ9000 is one of the most widely used host for the food-grade efficient protein expression system. In order to obtain high electrotransformation efficiency of NZ9000, single factor experiment was carried out to optimize the factors effecting electrotransformation efficiency, such as cell growth, glycine content, plasmid content, electric field strength, resuscitation medium and recovery time. The above key factors were further optimized by using response surface methodology and the optimum values for optical density OD600, glycine content and electric field strength were 0.2, 8 g/L and 12.5 kV/cm, respectively. The electrotransformation efficiency (3.76× 10^7 CFU/μg DNA) was increased by the present of 250 compared to that in the initial conditions. The optimized preparation method of L. lactis NZ9000 improves the electrotransformation efficiency, which lays a foundation for exploring the competence potential of L. lactis.