Direct electroporation as an alternative technique in transforming recombinant DNAs into lactobacillus lactis

A new technique in transforming recombinant DNAs bearing cop genes was established. Using this technique, an overnight ligation mixture was transformed directly into the competent cells of L. lactis without transforming into E. coli first. Transformants were selected based on blue colonies appearance and the ability to grow on chloramphenicol-containing M17G supplemented with X-Gluc and nisin as inducer. Transformation efficiencies of 1.52 x 103 CFU/Rg and 7.5 x 10' CFU/lig were obtained following electroporation with resistance of 400 and 200 ohm respectively. Recombinant plasmids were obtained from the transformants and plasmids bigger than plasmid vector pNZ8010 were selected as suspected bearing the cop genes. The presence of the inserted cop genes could be seen as 1.9 kb bands on 1% agarose gel as the products of PCR with specific primers. Keywords: direct electroporation � transformation efficiencie