The marine isolate Bacillus subtilis KMM 457, which produces bacillomycin D and two peptides with n-C-14 and iso-C-15 β-amino acids, was previously reported. In continuation of investigating components of the butanol extract from this strain's culture liquid, we isolated a compound (fraction 1) that inhibits growth of the yeast-like fungus Candida albicans but is inactive relative to gram-positive and gram-negative bacteria. Fraction 1 was obtained as a white powder (15 mg from 50 L culture liquid) via repeated adsorption chromatography over silica gel with gradient elution. Characterization using IR, UV, amino-acid analysis, MALDI MS, and NMR (PMR, 13C NMR, HMBC) revealed: solubility in polar solvents (alcohol, pyridine) but not nonpolar ones (hexane, CHCl3, benzene); IR absorption bands for peptide bond (1678, 1662, 1640, 1542, 1510 cm-1) and ester (1250 cm-1); UV absorption at 280-285 nm (characteristic of tyrosine); amino-acid composition identical to bacillomycin D (Asp:Tyr:Glu:Pro:Thr:Ser in ratio 2:1:1:1:1:1) plus an aliphatic β-amino acid; MALDI MS peaks at 1044 and 1058 Da (homologous peptides with different β-amino acids, with the 1058 Da peptide (C15-β-amino acid) dominant); NMR signals for a methoxy group (3.5 ppm in PMR, 51.2 ppm in 13C NMR) that coupled with the carbonyl of an acid (HMBC), indicating glutamic acid in fraction 1 exists as the methyl ester. Thus, fraction 1 is the methyl ester of bacillomycin D and represents a new member of iturin antibiotics, which are synthesized by different B. subtilis strains as combinations of homologs at the β-amino acid with a specific set, number, sequence, and configuration of amino acids in the peptide ring.