Twelve strains of filamentous fungi, most of them belonging to the Deuteromycetes class, were isolated from activated sludge adapted to the delignification effluent from a nitrocellulose industry and screened to be used in the treatment of the effluent. The screening experiment was carried out using the effluent without co-substrate, treated for 120 h and pH 5. Aspergillus 2BNL1, Aspergillus 1AAL1 and Lentinus edodes UEC 2019 showed the highest effluent color reduction rates between 83% and 95%. The white-rot fungus L. edodes UEC 2019 was used as the control for the decolorization. In addition to color reduction, total phenol was also reduced in 56% and 79% by Aspergillus 2BNL1 and L. edodes UEC 2019, respectively. A kinetic experiment showed that Aspergillus 2BNL1 and Aspergillus 1AAL1 reduced the effluent color in the range of 81-95% at the first 24 h while L. edodes required 72 h to achieve a similar result. UV/Visible spectra revealed that all fungi treatments were able to decrease the chromophore compounds present in the effluent, except Aspergillus 1AAL1 that increased the UV absorptions. The molar weight distribution analysis showed that the three fungi were able to change the pattern of the effluent chromatogram, probably by degradation of the high molecular weight compounds. (c) 2005 Elsevier Ltd. All rights reserved.