Structural Characterization of Lipopeptide Methyl Esters Produced by Bacillus licheniformis HSN 221
✍ Scribed by Yiming Li; Shizhong Yang; Bozhong Mu
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 208 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1612-1872
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✦ Synopsis
Lipopeptides and their analogues are of increasing interest due to their amphiphilic structures and potential applications in various fields. Three purified lipopeptides analogues were obtained at the same time after two-step column-chromatographic purification from cell-free broth cultivated by Bacillus licheniformis HSN 221. Analysis by ESI-MS, GC/MS, HPLC, and Q-TOF MS/MS revealed their primary structures as anteiso-C 15 -and iso-C 15 -b-hydroxy fatty acid-Gln-Leu-Leu-Val-MeAsp-Leu-Ile, anteiso-C 15and iso-C 15 -b-hydroxy fatty acid-MeGlu-Leu-Leu-Val-Asp-Leu-Ile and iso-C 16 -b-hydroxy fatty acid-Glu-Leu-Leu-Val-MeAsp-Leu-Ile, respectively. The production of two surfactin monomethyl esters and one lichenysin monomethyl ester directly from microorganisms is helpful to understand the variants of metabolites.
Introduction. -Biosurfactants are amphiphilic compounds produced by microorganisms and consist of glycolipids, lipopeptides, polysaccharide -protein complexes, phospholipids, fatty acids, and neutral lipids . They have superior advantages in surface and biological activities, including high biodegradability and compatibility, low critical micelle concentration, low toxicity, and low irritability of human skin [2] [3]. Therefore, they have potential applications in food, cosmetic, medicine, and petroleum industry.
Among these biosurfactants, lipopeptides are of increasing interest for researchers. They consist of a hydrophobic fatty acid moiety and a hydrophilic peptide moiety, which is mostly made up of a cyclic peptide with several amino acids in special sequences. The fatty acid moiety includes n-, iso-, and anteiso-form fatty acids with 13 -15 C-atoms [4] [5]. Although surfactin, one of the lipopeptides, was separated in 1968 and characterized in 1969 [6] [7], there has been a revival of interest in the characterization of various lipopeptides only in recent years [8 -12]. It has been found that various isoforms of surfactin and lichenysin, which are attractive powerful lipopeptides, including [Val7]surfactin , lichenysin G, and its isoforms [14], and C 12lipopeptide , are produced by Bacillus genus. The free carboxy (COOH) groups in lipopeptides are closely related to their properties. Lichenysin with only one free COOH group has shown a significant surface activity compared to surfactin with two free COOH groups in its peptide moiety .
Lipopeptide methyl esters have exhibited potential antiviral activities . They can be produced by several chemical ways such as MeOH esterification of surfactin in the presence of base or acid [9] [18] [19]. Here, we report the separation of three