Inhibitory activity of Paenibacillus polymyxa SCE2 against human pathogenic micro-organisms

Paenibacillus polymyxa strain SCE2 was shown to inhibit the growth of diffe rent potential human pathogenic bacterial strains and fungi in vitro. To de termine the genetic characterization of this antimicrobial substance, strai n SCE2 was transformed with plasmid pTV32(Ts), a delivery vector for Tn917- lac. After transposition, four mutants were shown to have lost their capabi lity to inhibit Micrococcus sp. and Staphylococcus aureus RN450, but they c ontinued to inhibit the growth of Corynebacterium fimi NCTC7547 and Escheri chia coli HB101. Hybridization experiments using the DNA of the four mutant s digested with different endonucleases and pTV32(Ts) as a probe showed tha t the place of insertion of Tn917-lac in the chromosome was the same in mut ants 4 and 36 and in mutants 31 and 59, but different between these pairs. It is thought possible that more than one antimicrobial substance is being produced by strain SCE2.