TRANSFORMATION OF BACILLUS-SUBTILIS, ANTIFUNGAL-ANTIBIOTIC ITURIN PRODUCERS WITH ISOLATED ANTIBIOTIC-RESISTANCE PLASMIDS

In order to obtain appropriate vectors to transform several strains of Bacillus subtilis, antifungal iturin producers, plasmids have been isolated as covalently closed circular deoxyribonucleic acid from antibiotic-resistant bacteria inhabited in composts. Eight plasmids coding antibiotic resistance transformed both competent cells of a derivative of B. subtilis Marburg 168 and protoplasts of B. subtilis NB22, an antifungal-antibiotic iturin producer, in the presence of polyethylene glycol. However, transformation efficiency was not high enough as a cloning host-vector system. To improve transformation efficiency, KCl-treatment method and electroporation method were applied to four iturin producers, and electroporation method was most effective for transformation with newly-isolated plasmids with great efficiency.