The factors influencing the activities of extracellular ligninolytic enzymes synthesized by white rot fungus, Phanerochaete chrysosporium, were investigated by batch culture experiments. The LiP activity was maximal under the nitrogen-sufficient condition, compared with the activities under both conditions of the nitrogen-limited and nitrogen-excess. The manganese-dependent peroxidase (MnP) activity was highest under nitrogen-limited condition. Veratryl alcohol was found to be the most important substrate enhancing lignin peroxidase (LiP) activity in carbon-limited medium. The decolorization of azo dye (Reactive Red 22) by P. chrysosporium in the presence of both LiP and MnP under carbon-limited condition was greater than that in the presence of MnP under nitrogen-limited condition. Two chlorinated substances (2,6-DCP and MCPA) were degraded under conditions of nitrogen-limitation and notrogen-sufficiency, The azo dyes were also decolorized by the crude extracellular ligninolytic enzymes from P. chrysosporium. Copyright (C) 1996 IAWQ.