The decolorization of dye and textile effluent byTrametes hirsutawas studied in both induced and non-induced media. A removal of 70-100% of the color was achieved through adsorption and the action of laccases. Laccase activity was increased significantly with the addition of grapefruit peel (4000 U/mL) and effluent with grapefruit peel (16,000 U/mL) in comparison with the basal medium (50 U/mL). Analysis of the expression of laccase isoenzymeslac-Bandlac-Trevealed clear differences in the expression of these genes. The low levels of expression oflac-Bin all media suggest a basal or constitutive gene expression, whereaslac-Twas over-expressed in the media with effluent, and showed an up/down regulation depending on culture conditions and time. The results obtained suggest that thelac-Tgene ofT. hirsutais involved in the decolorization of dyes.