Amperometric detection of lignin-degrading peroxidase activities from Phanerochaetechrysosporium

An amperometric enzyme sensor for rapid and simultaneous detection of the lignin-degrading peroxidase activities secreted by Phanerochaete chrysosporium was developed, using H2O2, hydroquinone and veratryl alcohol as substrates. In the amperometric measurement, samples of culture filtrate with different lignin-degrading peroxidase activities measured by spectrophotometry were placed into electrochemical cells. The slope of the current increase (Δcurrent/Δtime) upon the addition of H2O2 into the culture filtrate solution containing hydroquinone was used as the index for total activity of lignin peroxidase and manganese peroxidase. Then a specific detection of lignin peroxidase was achieved by the addition of veratryl alcohol, which led to current decrease due to the redox competition between veratryl alcohol and hydroquinone. A good linear correlation was found between the electrochemical response and lignin peroxidase activity, manganese peroxidase activity in the range of 8.14-29.79 U l−1 and 0.085-1.37 U l−1, respectively. A regression model was established describing the relationship. The amperometric sensor described here is more rapid, sensitive and precise than conventional spectrophotometric assays, free from interference of turbidity and UV-vis-light-absorbing substances. In this paper, it was also applied in the detection of lignin-degrading peroxidases in compost bioremediation using P. chrysosporium, showing considerable advantages.