Coal Depolymerising Activity and Haloperoxidase Activity of Mn Peroxidase fromFomes durissimusMTCC-1173

Mn peroxidase has been purified to homogeneity from the culture filtrate of a new fungal strain Fomes durissimus MTCC-1173 using concentration by ultrafiltration and anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The molecular mass of the purified enzyme has been found to be 42.0 kDa using SDS-PAGE analysis. The K m values using MnSO 4 and H 2 O 2 as the variable substrates in 50 mM lactic acid-sodium lactate buffer pH 4.5 at 30 ° C were 59  μ M and 32  μ M, respectively. The catalytic rate constants using MnSO 4 and H 2 O 2 were 22.4 s −1 and 14.0 s −1 , respectively, giving the values of k cat / K m 0.38  μ M −1 s −1 and 0.44  μ M −1 s −1 , respectively. The pH and temperature optima of the Mn peroxidase were 4 and 26 ° C, respectively. The purified MnP depolymerises humic acid in presence of H 2 O 2 . The purified Mn peroxidase exhibits haloperoxidase activity at low pH.