Effect of copper ions on the ligninolytic enzyme complex and the antioxidant enzyme activity in the white-rot fungus Trametes trogii 4(6)

摘要

White-rot fungi of the Phylum Basidiomycota are quite promising in ligninolytic enzyme production and the optimization of their synthesis is of particular significance. The aim of this study was to investigate the effect of enhanced concentration of copper (Cu) ions (25-1000g/ml) on the activity of the ligninolytic enzyme complex (laccase, Lac; lignin peroxidase, LiP; Mn-peroxidase, MnP) in Trametes trogii 4(6), as well as the changes in the antioxidant cell response. All concentrations tested reduced significantly in growth and glucose consumption. Cu ions affected the ligninolytic enzyme activity in a dose dependent manner. Concentrations in the range of 25-100g/ml strongly stimulated Lac production (a 5-6-fold increase compared to the control). LiP activity was also induced by Cu, with the peak value being recorded following exposure to 50g/ml metal ions. In contrast, the addition of Cu ions had a positive effect on MnP activity at a concentration higher than 100g/ml. The maximum enzyme level was achieved at 1000g/ml. The results obtained on superoxide dismutase and catalase activities indicated that exposure of T. trogii 4(6) mycelia to Cu ions promoted oxidative stress. Both enzyme activities were co-ordinately produced with Lac and LiP but not co-ordinately with MnP.