Surfactin Isoforms from Bacillus subtilis HSO121: Separation and Characterization
Natural surfactin is a mixture of cyclic lipopeptides built from variants of a heptapeptide and a ß-hydroxy fatty acid. A biosurfactant-producing strain, Bacillus Sabtilis HSO121, was isolated from the production water of an oil field. The strain was able to produce eight surfactin isoforms which have been isolated by acid-precipitation followed by extraction into methanol. A novel procedure for the purification of surfactin was achieved. It consists of a solid-phase extraction on C18 gel followed by reversed-phase high performance liquid chromatography using Prep. HiQ sil C18W, column. The surfactin isoforms were eluted by linear acetonitrile gradient from 80-100%%. The peaks were analyzed by TLC on silica gel, and after acid hydrolysis their amino acid compositions were determined by HPLC analysis. Eight isoforms of surfactin had nearly the same amino acid composition and appeared a single spot in TLC. According to the Rf values with the amino acid composition, these peaks belong to the surfactin group of lipopeptides. Infrared analysis of the purified samples also revealed a pattern similar to that of surfactin. This is a very effective method for isolating and fractionating lipopeptides, of the same or different nature.
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Document Type: Research Article
Publication date: 01 March 2008
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- Protein & Peptide Letters publishes short papers in all important aspects of protein and peptide research, including structural studies, recombinant expression, function, synthesis, enzymology, immunology, molecular modeling, drug design etc. Manuscripts must have a significant element of novelty, timeliness and urgency that merit rapid publication. Reports of crystallisation, and preliminary structure determinations of biologically important proteins are acceptable. Purely theoretical papers are also acceptable provided they provide new insight into the principles of protein/peptide structure and function.