Dual gradient macroporous resin column chromatography for concurrent separation and purification of three families of marine bacterial lipopeptides from cell free broth

•Sorption characteristics of lipopeptides were studied on various macroporous resins.•Factors affecting the static and dynamic adsorption were optimized.•A dual pH-solvent gradient elution strategy was developed.•Established a method for concurrent recovery and purification of lipopeptides.

A simple and efficient dual-gradient elution strategy for the separation and purification of marine bacterial lipopeptides was developed in macroporous resin column chromatography. Preliminary batch adsorption studies conducted on four different resins revealed that a non-polar resin, HP-20, exhibited the highest adsorption capacity. The optimal conditions yielding maximum adsorption of lipopeptides on to this resin were as follows: temperature = 40 °C, resin dosage = 10 g L−1 and initial lipopeptide concentration = 3 g L−1. While employing a simple stepwise solvent gradient elution under optimal conditions, three lipopeptide families, namely, iturin, fengycin and surfactin could be separated with poor resolution. However, the resolution was significantly improved after implementing a family specific dual-gradient elution strategy, wherein, both the solvent composition and pH of the mobile phase were simultaneously varied. Using this approach, lipopeptides were effectively resolved and purities up to 68.3% (iturin), 77.6% (fengycin) and 91.6% (surfactin) were achieved. To the best of our knowledge, this is the first report on the macroporous adsorption resin (MAR) chromatography employing family specific dual-gradient elution strategy for simultaneous recovery and purification of lipopeptides directly from cell free culture broth.

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