Synthesis of enhanced biosurfactant by Bacillus subtilis MTCC 2423 at 45 degrees C by foam fractionation

Production of a lipopeptide surfactant in a 6.5-L batch fermentor was carri ed out using Bacillus subtilis MTCC 2423 at 45 degreesC. A good yield was o btained from sucrose (2%) substrate fermentation by continuous removal of t he product by foam fractionation. The biosurfactant was recovered from coll apsed foam by acid precipitation. The biosurfactant yield (4.5 g/L was abou t 4.5 times higher than the yield (ca. 1 g/L obtained by shake-flask fermen tation. Surface activity of the collapsed foam was very high, and total sur face activity was observed in the collapsed foam. The structural characteri zation of this biosurfactant produced at 45 degreesC by the strain used in this study was recently reported. The biosurfactant was analyzed by thin-la yer chromatography, infrared, H-1 nuclear magnetic resonance, and mass spec troscopy and was found to be identical to surfactin, a lipopeptide surfacta nt.