Cloning of a Laccase Gene from a Novel Basidiomycete <Emphasis Type="Italic">Trametes</Emphasis> sp. 420 and Its Heterologous Expression in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

The laccase gene lacD, cloned from a novel laccase-producing basidiomycete Trametes sp. 420, contained 2,052 base pairs (bp) interrupted by 8 introns. lacD displayed a relatively high homology with laccase genes from other white rot fungi, whereas the homology between lacD and laccase genes from plants, insects, or bacteria was less than 25%. A 498–amino acid peptide encoded by the lacD cDNA was heterologously expressed in the Pichia pastoris strain GS115, resulting in the highest yield of laccase (8.3 × 10⁴ U/l) as determined with ABTS (2,2′-azinobis 3-ethylbenzothia-zoline-6-sulfonic acid]) as the substrate. Additionally, the enzyme activity of recombinant laccase on decolorization of some industrial dyes was assessed.