<jats:title>Abstract</jats:title><jats:p>A new surfactin isomer (1) was isolated from a mangrove bacteria strain ‘<jats:italic>Bacillus</jats:italic> sp’. Its structure was identified, and full assignments of <jats:sup>1</jats:sup>H and <jats:sup>13</jats:sup>C NMR spectral data were achieved for the first time by a combination of mass spectrometry and 1D and 2D NMR experiments including DEPT, <jats:sup>1</jats:sup>H<jats:sup>1</jats:sup>H COSY, HSQC, HMBC, TOCSY, ROESY, and HSQC‐TOCSY. The NMR spectral data of eight known analogs (2–9) are also reported. Copyright © 2007 John Wiley & Sons, Ltd.