Flipsen_1996_Chem.Phys.Lipids_84_105

Interfacial events during lipid hydrolysis by cutinase are described as measured with the oil-drop tensiometer. A linear relation between enzyme concentration and initial decrease of oil-water interface tension (gamma o/w) due to lipolytic activity was observed. The amount of hydrolysis products showed a non-linear relation with gamma o/w. Hydrolysis is linear with time, even when the area occupied by the fatty acid molecules exceeds the drop surface by a factor 7000. At pH 9.0, fatty acids were found to partition mainly in the oil phase. Formation of calcium soaps and ionization increase the impact of fatty acids on gamma o/w without affecting enzyme activity. The presence of fatty acids at the interface, added prior to cutinase, delayed hydrolysis effects on gamma o/w. Fatty acids in the water phase almost completely abolished adsorption effects on gamma o/w, when the concentration was over the critical micellar concentration (cmc).