Lipases are secreted into the culture medium by many bacteria and fungi. They catalyse not only the hydrolysis but also the synthesis of long-chain acylglycerols. Important uses in biotechnology include their addition to detergents, the manufacture of food ingredients, pitch control in the pulp and paper industry, and biocatalysis of stereoselective transformations. This makes them the most widely used class of enzymes in organic chemistry. Immobilization in hydrophobic sol-gel matrices and in vitro evolution are promising novel approaches to increasing the stability or enantioselectivity, respectively, of lipases.