Isolation and Analysis of Lipopeptides and High Molecular Weight Biosurfactants


High molecular weight biosurfactants are produced from a number of different bacteria and comprise lipoproteins, proteins, polysaccharides, lipopolysaccharides or complexes containing several of these structural types, many of which have yet to be fully characterized. Lipopeptide biosurfactants are cyclic compounds and are most commonly isolated from Bacillus and Pseudomonas strains. A great deal of research has been carried out on these cyclic lipopeptides and their structures have been fully characterized. The ability to isolate, purify and characterize these structures is extremely important, providing detailed information with regard to different cultivation condition and biological activities. Similar methods can be used for both lipopeptides and biopolymers especially when attempting to determine their amino acid sequences. The experimental techniques used to isolate, purify and analyses these biosurfactant are widely varied from simple colorimetric assays giving an approximate indication of the type of compounds present to the more complex mass spectrometric techniques that provide information on molecular mass and structural features. Mass spectrometry provides essential information in the identification of these structures using sophisticated MS/MS experiments and software technologies. The use of Edman degradation can help confirm the results observed from de novo sequencing experiments, thus providing further confirmation of amino acid sequence of both lipopeptides and protein containing biopolymers. This paper details information on the most commonly reported techniques used to analyze these types of biosurfactants.