Characterization of laccase from native Dictyopanus pusillus

Lignolytic enzymes are a group of biocatalysts with potential applications in delignification and bioremediation. The enzymatic delignification process is a green chemistry alternative for the pretreatment of lignocellulosic material, providing a means for the efficient removal of lignin and the synthesis of biologically active compounds such as monolignols. Laccases (EC 1.10.3.2) are the most studied enzymes in delignification processes and Basidiomycete fungi are the main source. The aim of this study was to identify the gene sequence and protein structure of a protein band identified with a laccase activity from an enzymatic extract obtained by solid-state fermentation (SSF) of a native Dictyopanus pusillus. The enzymatic extract from D. pusillus was concentrated and purified by fast protein liquid chromatography (FPLC) using an anion exchanger. SDS-PAGE and native PAGE were used to determine the molecular weight and activity of the bands obtained. Tryptic digestion and Micro-HPLC-MS analyses were performed to identify peptides belonging to the protein band identified with laccase activity. From those peptides, degenerate primers were designed to amplify the coding gene sequence from native D. pusillus. The DNA sequence identified was used to elucidate the primary structure of the native laccase. These results confirm the expression of a new laccase in D. pusillus, further allowing overproduction of this enzyme in a heterologous system.