Separation of lipopolysaccharides containing different fatty acid chains using hydrophobic interaction chromatography

Lipopolysaccharides, known as endotoxins, are major components in the outer membrane of most Gram-negative bacteria. Because of their amphipathic property, it is difficult to separate lipopolysaccharides. In this study, hydrophobic interaction chromatography was used for the separation of lipopolysaccharides containing different numbers of fatty acid chains. Three species of lipopolysaccharides were extracted from Escherichia coli W3110, MLK1067, and MKV15b, respectively. Their interactions with three types of hydrophobic matrixes Butyl-Sepharose, Phenyl-Sepharose and Octyl-Sepharose were investigated. Several organic solvents were used to elute the bound lipopolysaccharides from different matrixes. Butyl-Sepharose, propyl alcohol and 0.8 mol l−1 sodium acetate (pH 4.5) loading buffer were chosen for the best separation system, and lipopolysaccharides containing different fatty acid chains were separated. This system might be useful for removing the contaminated lipopolysaccharides from proteins produced by E. coli, or separating different species of lipopolysaccharides.