Decolourization of Poly R-478 and Poly S-119 by Chrysosporium lignorum was indicative of lignin peroxidase and manganese peroxidase activity when the fungus was cultured under static conditions or immobilized in a 2 litre bioreactor. Immobilization resulted in an ability to produce both enzymes over a longer period of time, with a maximum MnP activity of 75 U/ug(-1) on day 37 in immobilized cultures compared to day 15 in statically grown cultures.