Identification and characterization of two peroxidases from Lichtheimia corymbifera

Abstract The fungus Lichtheimia corymbifera w as isolated on mineral salt medium (MSM) supplemented with direct green azo dye as a sole carbon source and identified by sequencing the ITS1-ITS4 gene region. This fungus showed lignin peroxidase activity when grown in liquid MSM supplemented with methyl red azo dye as a sole carbon source. The lignin peroxidase was isolated by ammonium sulfate precipitation, and purified by DEAE-SephadexA50 column chromatography and gradient SDS-PAGE separation. The enzyme bands on gels were identified by reaction with pyrogallol and hydrogen peroxide, picked, and hydrolyzed by tryps in followed by amino acids sequencing by LC/MS/MS. Two different peroxidases were identified by homology to entries in the PEAKS database and Uni Prot repository. The first (accession number A0A068RV79) was comprised of 360 AA residues with MW 40.16KD. The second (accession number A0A068S1N8) was comprised of 271 AA with a MW 30.91KD. A kinetic study of the most abundant peroxidase (MW 30.91 KD) showed a maximum enzyme activity (V max ) (10.23 mg/ml/20 s) and the lowest K m value (0.33 μM hydrogen peroxide) at 0.8 μM of hydrogen peroxide and 32 μM of pyrogallol. The kinetics of this enzyme was reported for the first time in this work; furthermore, no previous articles reported the ability of L. corymbifera to degrade the azo dyes.