Screening of a Bacillus subtilis strain producing multiple types of cyclic lipopeptides and evaluation of their surface-tension-lowering activities

Abstract

Sixty Bacillus subtilis strains were investigated for their ability to produce cyclic lipopeptides (CLPs). Among them, B. subtilis NBRC 109107 produced at least three types of CLPs by high-performance liquid chromatography (HPLC) analysis, and these CLPs were thought to be surfactin, iturin A, and fengycin by polymerase chain reaction amplification of respective CLP synthetase-encoding genes. However, after HPLC fractionation and purification, structural analysis of the CLPs revealed that these were surfactin homologues, iturin A, and unknown CLPs, whose surface-tension-lowering activities were 29.4, 56.7, and 48.6 mN/m, respectively. By contrast, fengycin was not detected.