SCREENING FOR THE PRESENCE OF BIOSYNTHETIC GENES FOR ANTIMICROBIAL LIPOPEPTIDES IN NATURAL ISOLATES OF BACILLUS SP.

A collection of 205 natural isolates of Bacillus was tested for the presence of genes for biosynthesis of antimicrobial lipopeptides, iturin, surfactin, fengycin and bacillomycin D. For the detection of iturin producers by PCR screening, we used forward ITUP1-F and reverse ITUP2-R primers which are capable of detecting a 2-kb region that includes the intergenic sequence between the ituA and ituB genes. A 675-bp fragment from the gene sfp from B. subtilis encoding 4'-phosphopantetheinyl transferase involved in the biosynthesis of surfactin was targeted for amplification by using primers P17 and P18. Other two pairs of primers were BACC1F and BACC1R for bacillomycin D and FEND1F and FEND1R for potential fengycin producers, respectively. The results of the screening showed that the majority of tested strains had more than one biosynthetic operon, since 81% possessed the genes for bacillomycin D production, 54% for surfactin, 38% for iturin and 25% for fengycin production.