Identification of fengycin homologues from Bacillus subtilis with ESI-MS/CID

Bacillus subtilis fmbJ (CGMCC no.0943) was used to produce lipopeptides antibiotics fengycin. The fengycin mixture was precipitated with 6 N HCl and extracted by methanol. Electrospray ionization mass spectrometry/collision-induced dissociation (ESI-MS/CID) were used to analyze the fengycin mixture. In the ESI-MS/CID spectra of fengycin molecular ions, production ions (m/z 1080, m/z 966, m/z 1108 and m/z 994) were always detected. Therefore, these production ions (m/z 1080, m/z 966, m/z 1108 and m/z 994) could be used as fingerprints to quickly detect fengycin A and fengycin B. By the method of ESI-MS/CID, six homologues of fengycin A with C14 to 19 and four homologues of fengycin B with C14 to 17 were characterized. The method will be useful for rapidly determining whether a strain produces fengycin homologues.