Coal Depolymerising Activity and Haloperoxidase Activity of Mn Peroxidase from Fomes durissimus MTCC-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 µM and 32 µM, 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 µM(-1)s(-1) and 0.44 µM(-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.