Optimization of inducing conditions on rHAP producing E.coli

Purpose To study the inducing factors influencing the expression of rHAP by recombinant Escherichia coli strain,using lactose as an inducer instead of IPTG.Methods The relationship between bacterial growth and density,the dosage of inducer IPTG and lactose,the induction time and the expression level of recombinant protein were investigated.Results The optimized inducing time was found to be that when the concentration of the culture reached A560 value 3.0.Induced by lactose at a concentration of 0.5 g/L the expression of rHAP was the same as that induced by IPTG.The time of the induction could affect the expression level of the target protein.Conclusion The optimized inducing conditions were obtained to express rHAP in E.coli.In the manufacture of such a recombinant protein,using lactose instead of IPTG can reduce the cost.It could lay a foundation for production on larger scale.