Decolorization of recalcitrant dyes by an indigenous strain of white rot fungus isolated from bark of dead tree, WR-1 identified as Ganoderma sp. was investigated. The fermentation medium was optimized using a combination of one factor at a time and orthogonal array method. Maximum decolorization (96%) of 100 ppm amaranth was achieved in 8 h with optimized medium containing 2% starch and 0.125% yeast extract. Rate of dye decolorization by the indigenous isolate Ganoderma sp. WR-1 was very high compared to the most widely used strains of Trametes versicolor and Phanerochaete chrysosporitum. The broad-spectrum decolorization efficiency of the isolate was assessed using chemically different dyes. The isolate was further evaluated for the decolorization of industrial effluent. Complete decolorization was achieved in 12 days. (c) 2006 Elsevier Ltd. All rights reserved.