Thus, the foam fractionation process was able to increase the product purity. The chromatogram of crude lipopeptides showed peaks with retention times similar to the standardsurfactin (98% pure) from Sigma-Aldrich at 11.02, 14.88, and16.36 min (Fig. 7c). Davis et al. [36] also applied foam fractionation technique to separate lipopeptide from culture medium of Bacillus subtilis ATCC 21332. They found that a mean surfactin enrichmentof 2.9 was reached in the cell-free process compared to 1.7 for thecell-containing system and the surfactin recovery for the cell-freeand cell-containing process were similar, 97 and 97%, respectively.