An Efficient Method for the Recovery and Separation of Surfactin from Fermentation Broth by Extraction-Back Extraction

Surfactin has potential applications in the pharmaceutical, food and other industries, while the separation of surfactin is still a challenge for commercialization. A surfactin separation method consisted of three steps was introduced, i.e the acid precipitate of fermentation broth was added to methanol at a solid: liquid ratio of 1:10–15, the alcoholic extract was obtained through filtration. An extraction system was established by adding the alcohol extract to hexane, ethyl acetate, and water, with the same volume to that of the alcohol extract, the pH of the extraction was adjusted to 2.0, and the organic phase was obtained after extraction. Finally, the aqueous phase of the extraction system was mixed with the organic phase, and the pH was adjusted to 7.0–8.0. The aqueous phase was freeze-dried to obtain surfactin with a content of 69.51%. The method is feasible for industrial application in the separation of surfactin during extraction.