Electroporation and expression of plasmid pBR322 in Klebsiella aerogenes NCTC 418 and plasmid pRK2501 in Pseudomonas putida CYM 318.

Klebsiella aerogenes NCTC 418 and Pseudomonas putida CYM 318 were transformed via high-voltage electroporation with plasmids pBR322 and pRK2501, respectively. The number of transformants obtained was dependent on the applied voltage, capacitance, and cell recovery procedure. For example, 7.87 x 10(4) transformants/micrograms DNA were obtained at 2500 V, 25 muF when K. aerogenes cells were electroporated with pBR322 DNA. A lower voltage (1500) and capacitance (3 muF) yielded 2.4 x 10(3) transformants/micrograms DNA. P. putida CYM 318 required a 24 h outgrowth period to assist in the recovery of transformants containing pRK2501. Electroporation may be a useful protocol to transform bacterial strains that are not easily transformed by traditional methods.