title: Structural characterization of lipopeptides from Brevibacillus brevis HOB1.
abstract: Brevibacillus brevis HOB1 was isolated from the formation water of an oil field and found to produce lipopeptides. The separation of lipopeptides was successfully achieved by reversed-phase high-performance liquid chromatography (HPLC) leading to nine separated peaks. The chemical structures of these lipopeptides were studied by means of electrospray ionization mass spectrometry (ESI-MS), gas chromatography-mass spectrometry (GC/MS), HPLC and electrospray ionization tandem mass spectrometry (ESI-MS/MS). As the results, all the lipopeptides had peptide parts with the same amino acid composition of Asp, Glu, Val, and Leu in the molar ratio 1:1:1:4, while the lipid part was composed of C(13)-C(15) beta-hydroxy fatty acids. As the sequence of fraction 1 was determined to be N-Glu-Leu-Leu-Val-Asp-Leu-Leu-C, the same as surfactin, they were proposed to be surfactin isoforms. Fraction 4 (C(15) surfactin) exhibited a good surface activity of 26.8 mN/m with CMC of 9 x 10(-6 )M. Surfactin is a powerful biosurfactant possessing biological activities. As far as we know, Br. brevis is a new surfactin-producing species.
authors.affiliation: State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Wang
authors.forename: Namir I A
authors.initials: NI
authors.lastname: Haddad
authors.forename: Shi-Zhong
authors.initials: SZ
authors.lastname: Yang
authors.forename: Bo-Zhong
authors.initials: BZ
authors.lastname: Mu
mesh_terms: D000595:Amino Acid Sequence; D056449:Bacillales / Q000737:chemistry*; D055666:Lipopeptides / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D013500:Surface Tension; D053719:Tandem Mass Spectrometry
chemical_list: D055666:Lipopeptides