Liquid membrane extraction of bio-active amphiphilic substances: Recovery of surfactin

The interest of application of liquid membrane (pertraction) processes for recovery of biosurfactants from aqueous media was demonstrated. Transport of pure surfactin in three-liquid-phase system was studied. Surfactin was successfully extracted from slightly acid media (pH 5.65-6.05) applying batch pertraction in a rotating discs contactor and using n-heptane as liquid membrane. The process efficiency was found to be strongly affected by the feed solution acidity (83% at pH(F) 6.05 and 97% at pH(F) 5.65 after 4 h pertraction). An atypical pH effect was observed when the behaviour of surfactin extraction from aqueous media by non-polar solvents (n-heptane and n-octane) was studied. The obtained high extraction degrees from both acid and basic media and the clearly reduced degree of extraction from neutral media could be attributed to the different conformations of surfactin in these media. (C) 2008 Published by Elsevier B.V.