Oxidation of polyaromatic hydrocarbons in systems containing water miscible organic solvents by the lignin peroxidase of Gleophyllum striatum MTCC-1117

Lignin peroxidase has been purified to homogeneity using a process of concentration by ultrafiltration and anion exchange chromatography on diethylaminoethyl (DEAE) cellulose from the liquid culture filtrate of the brown rot fungi Gleophyllum striatum MTCC-1117. The molecular mass of the purified enzyme is 43 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The K-m values for the enzyme using veratryl alcohol, hydrogen peroxide and n-propanol were 66 mu M, 82 mu M and 476 mu M, respectively. The pH and temperature optima of the enzyme were 2.8 and 25 degrees C, respectively. The enzyme is completely inhibited by 20% of the water miscible organic solvents acetone dioxane, diethylether, acetonitrile and dimethylformamide. The lignin peroxidase oxidizes polycyclic aromatic hydrocarbons pyrene, acenaphthene, anthracene, dibenothiophene and 9-methyl anthracene.