StrainsGALG20 and MG1655endArecA were superior to DH5 since high contents of pDNA were obtained in alkaline lysates and the final product fulfilled the requirements recommended bythe Food and Drug Administration (FDA) (CBER/FDA, 2007). The plasmids obtained from each specific strain were also used to transfect cultured CHO cells. No difference was observed between the samples regarding transfection efficiency (data not shown).