2.5 Screening of the mutant library
Transformants were selected on LB plates containing Zeo and colonies were then transferred to LB plates containing 50 mg/L chlorpyrifos using sterile toothpick. Strain BPC1was used as control. After incubation at 37 ℃ for 12 h, the MPH activity of each colony was determined by the size of transparent halos. Mutants with larger halo were selected for further verification.
2.6 MPH purification and chlorpyrifos-hydrolyzing