Lignin-degrading enzymes secreted by white rot fungi play an important role in the degradation of lignin and persistent organic pollutants (POPs).In this study,effect of environmental C/N ratio on the activities of lignin-degrading enzymes,lignin peroxide (LiP) and manganese peroxidase (MnP),produced by Phanerochaete chrysosporium,a white rot fungus,was investigated.Glucose was used as C source,and ammonium tartrate of different concentrations was used as N source to provide different C/N ratios.Relationships between LiP and MnP activities and environmental C/N ratio were explored.The results showed that the higher the N source concentration,the faster the mycelium pellets aged.The faster the mycelium dry weight increased,the higher the LiP and MnP activities.A high C/N ratio was a necessary condition for the secretion of LiP or MnP.In addition,mycelium dry weight essentially affected enzyme activities.In the 122 C/N ratio and 50 C/N ratio treatments,mycelium dry weight essentially affected MnP activity and both LiP and MnP activities,respectively.