Optimization of refolding conditions of Serratia marcescens lipase from inclusion body by orthogonal test.

Objective To optimize the refolding conditions of Serratia marcescens lipase from inclusion body expressed by Escherichia coli.Methods An orthogonal test was designed in order to screen the key factors on lipase refolding,such as the ion strength,pH,temperature of refolding and the concentration of urea in the refolding buffer.Then,the further optimization was made on the key factors.Results After refolding for 12 h,the activity of lipase was up to 3 500 U/L under the optimum refolding conditions with 20 mmol/L Tris-HCl(pH 7.0),0.8 mol/L urea and 1 mmol/L Ca2+ in the refolding buffer at 30 ℃.Conclusion The ion strength and pH of refolding buffer can be the key factors for lipase refolding.The lipase refolding can be promoted with the presence of Ca2+.