E. coli BW23473 electro-competent cell aliquots were taken out from -70ºC freezer, thawed on ice and were mixed with 1-2 lplasmid DNA. Mixture was pulsed with the Gene Pulser® electroporation apparatus (Bio-Rad),set at 1800 Volts, 25 μF and 200 Ω,in a chilled 0.1 cm electroporation cuvette. After electric pulse, 1 ml LB medium was immediately added to the cuvette and suspension was transferred to a 1.5 ml sterile microcentrifuge tube. Cells were incubatedat 37°C and 200 rpm for 1 h, centrifuged and were plated on LB-agar plates containing kanamycin (30 μg/ml). Transformants were colony purifiedon LB-kanamycin plates. Positive clones were verified by colony PCR and inoculated in LB-liquid medium containing kanamycin (30 μg/ml) for plasmid isolation

Transformation of E. coliBW23473 cells by electroporation