[Stereum hirsutum (Wild) Pers. action in dye degradation].

Stereum hirsutum, a white rot fungus, has a good growth in solid state fermentation. This was carried on with wheat bran, soy bran and a mixture of both. Mycelia grown on soy bran showed the highest decolorization activity on Ponceau 2R (xylidine), indigo carmine and malachite green. Optimal relationship between decolorization and detoxification of malachite green was 30 g of fresh weight (mycelia plus substrate) in 500 ml malachite green solution, 42 U/l of laccase was measured in this solution. Decolorization was carried on without the addition either of nutrients or mediators. Conditions for maximal decolorization did not agree with those for maximal ligninolytic enzyme production, but effectiveness of laccase activity on decolorization was evidenced by electrophoretic analysis, that allowed laccase identification and its decolorization activity in gels stained with indigo carmine and malachite green, with ABTS as mediator. Detoxification was assayed using the sensible fungus Phanerochaete chrysosporium.