Purification, characterisation and coal depolymerisation activity of lignin peroxidase from Lenzitus betulina MTCC-1183.

Lignin peroxidase from the culture filtrate of Lenzitus betulina MTCC-1183 has been purified to homogeneity using concentration by ultrafiltration and anion exchange chromatography on DEAE cellulose. The molecular weight of the purified lignin peroxidase using SDS-PAGE analysis was 43 kDa. Specific activity of the enzyme was 29.58 IU/mg. The K(m) values for veratryl alcohol and H2O2 for the purified enzyme were 54 microM and 81 microM, respectively. The k(cat) value of the purified enzyme was 2.3 s(-1) using 3,4-dimethoxybenzyl alcohol as the substrate. The optimal conditions for the lignin peroxidase assay were detected at pH 2.4 and 22 degrees C. Thermal stability of the purified enzyme has also been studied and its activation energy for deactivation was 287 kJ/mol. The purified lignin peroxidase depolymerised humic acid in presence of H2O2. Depolymerisation of coal by the L. betulina MTCC-1183 has been demonstrated using humic acid as a model of coal.