Characterization and decolorization ability of a laccase from Panus rudis

A laccase from Panus rudis was produced constitutively in defined shaken liquid culture without induction. The purified enzyme of 58 kDa contained 8% carbohydrate and had an isoelectric point of 3.5. The optimal pH of the enzyme is 3.5 and the optimal temperature is 60 °C with ABTS as the substrate. The Km of ABTS is 0.10 mM. The first 20 residues at the amino terminus were determined and the cDNA sequence encoding the enzyme was isolated by RT-PCR. The highest identity of the predicted amino acid sequence is 67% with the sequence of laccase from Lentinula edodes. The enzyme had excellent ability to decolorize anthraquinone dye (Acid Green 27) without any redox mediators, as well as azo and indigo dyes (Acid Violet 7 and Indigo Carmine) mediated by ABTS. Compared with other laccases in dyes decolorization, a very small amount of PrL could lead to effective dyes decolorization.