Characterization of a novel manganese peroxidase purified from solid state culture of Trametes versicolor IBL-04

A novel manganese peroxidase (MnP) produced by an indigenous white rot fungal strain Trametes versicolor IBL-04 in solid state medium of corncobs was purified and characterized. The fungus produced 964U/mL MnP in the presence of additional carbon (glucose) and nitrogen (yeast extract) supplements added at a C:N ratio of 25:1, 1mM Tween-80 (1mL), 1mM MnSO4 (1mL), and 1mM CuSO4 (1mL). The MnP was purified by ammonium sulfate fractionation (65% saturation) and dialysis, followed by Sephadex G-100 gel filtration chromatography. Purification procedures resulted in 2.4-fold purification with an overall yield and specific activity of 3.4% and 660 U/mg, respectively. The purified MnP was monomeric of molecular weight of 43 kDa, showing a single band on sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE). The enzyme was optimally active at pH 5 and 50oC and was stable for 1 h over a broad range of pH (4-7) and temperature (40-65oC). Kinetic constants KM and Vmax of purified MnP were 70 µM and 540 U/mL for MnSO4 substrate. The effect of possible activators and inhibitors of enzyme were also investigated, and it was observed that EDTA, Cystein, and Ag+ caused MnP inhibition and inactivation to different extents, whereas MnP was activated by 4 and 3 mM of Cu2+ and Fe2+, respectively. High thermo-stability, low KM and high Vmax features of this novel MnP isolated from culture filtrate of T. versicolor IBL-04 suggests its suitability for various industrial and biotechnological applications.