Bacillus spp. produce a variety of membrane-active lipopeptides that are of pharmaceutical and agricultural interest, and include surfactins, fengycins and iturins (Bonmatin et al., 2003). These compounds occur as related isoforms that differ in some amino acid substitutions and length of the fatty Sirolimus acid side chains. Surfactins and iturins are composed of a heptapeptide linked to a β-hydroxyfatty acid, whereas fengycin is a lipodecapeptide (Fig. 1). These

compounds have powerful antibacterial properties, which are a consequence of altering membrane integrity (Peypoux et al., 1999). Pozol is a nonalcoholic beverage from south-east Mexico, made from lime-treated kernals of corn, which are ground, wrapped in banana leaves and allowed Trichostatin A to ferment. The microbiology of Pozol has been studied, mainly focusing on the lactic acid bacteria involved in the fermentation (Escalante et al., 2001; Diaz-Ruiz et al., 2003). In addition to being consumed as food, the early Mayans used it as a treatment for intestinal complaints, diarrhoea and skin infections. Ray et al. (2000) isolated a bacterial

strain from Pozol, which has antibacterial and antifungal activities, and probably contributes to its curative properties. The isolate’s physiological and biochemical characteristics indicated that it belongs to the Bacillus genus, and 16S rRNA gene sequencing revealed that it is most closely related to Bacillus subtilis 6633. Further investigation of the strain’s antibiotic properties revealed that it produces the antifungal lipopeptide iturin A, and the antibacterial

compounds bacilysin and chlorotetaine (Phister et al., 2004). Recently, Moran et al. (2009) reported that fluorinated iturin A is produced when Bacillus sp. CS93 is incubated in the presence of fluorotyrosine. In this paper, we describe the detection of other lipopeptides in the culture supernatants of Bacillus sp. CS93 and the corresponding biosynthetic genes. Bacillus sp. CS93 (NRRL β-21974) was obtained from the Microbial Genomics and Bioprocessing Research Unit, National Center for Agricultural Cyclin-dependent kinase 3 Utilization Research, Peoria, IL. Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae were obtained from the culture collection of the School of Biomolecular and Biomedical Science, University College Dublin. The bacteria were maintained on tryptone soya agar (TSA) slopes at 4 °C; S. cerevisiae was maintained on yeast universal medium. Escherichia coli XL1-Blue and E. coli DH5α were obtained from Stratagene (La Jolla, CA), and were maintained as glycerol stocks (40% v/v) at −80 °C. Bacillus sp. CS93 was inoculated from an agar slope (TSA) into 50 mL Fred Waksman basic 77 supplemented with l-proline (1% w/v) and sodium nitrate (1% w/v) in 250-mL Erlenmeyer flasks and incubated at 30 or 37 °C and shaking at 200 r.p.m.