The purpose with the proposed project is to provide a better understanding of structural changes in interfacial lipid layers due action of lipolytic enzymes. In this study we will use the recently developed spin-freeze-thaw technique to form stable, uniform triolein films with thicknesses of ~2 micrometers by spin coating the oil onto hydrophobically modified silicon substrates. By using inactive and active lipase (Thermomyces Lanuginosa Lipase, TLL) we will be able to discriminate between the adsorption of the enzyme and the consequences of the TLL action on the triolein layer. Objectives are1. To determine the location and activity of TLL at the oil-water interface ¿ by using wild type and inactive mutant of TLL.2. To measure the structural changes of the oil-water interface, i.e. formation of lipid liquid crystalline phases in the interfacial layer due to lipolysis versus time