A bioemulsifier excreting bacterium of the species Peudomonas cepacia was isolated after a screening procedure using n-dodecane as carbon source. The partly purified bioemulsifier was preliminarily identified as a mixture of glycolipids. A decrease of the surface tension to 37 mN/m and a CMC of 5 mg/1 could be measured with the bioemulsifier GL-K12. Using sunflower oil as main carbon source, up to 7.1 g/1 bioemulsifier could be produced in oxygen and nitrogen limited fermentations on a scale of 300 1. The biodegradation of Aroclor 1242 in liquid cultures by a bacterial mixed population was enhanced by GL-K12 when added at biosurfactant concentrations of 0.2 g/l or more. The most positive effect was noted in the degradation of PCB congeners with 3 Cl atoms with an increase of up to 100%.