Among yeast species, Yarrowia lipolytica is one of the highest producers of extracellular proteins ( acid, neutral and alkaline proteases, ácid phosphatase, ribonucleases and lipases). Lipases ( triacylglycerol hydrolases) are important enzymes in fat metabolism, catalyzing the breakdown of triacilglycerols to free fatty acids and glycerol. Owing to the very low solubility of ther natural substrats, this hydrolysis is catalysed at the interfase beteween an insoluble substrat and the aqueous phase in which the enzyme is solubilized. This feature distinguishes them from esterases, which preferentially catalyze the hydrolisys of soluble esters in water.