• Time (in days) necessary for the fungus to occupy the whole Petri dish;
• D: complete decolorization; P: partial decolorization; no: no decolorization; nd: not determined; HI: decolorization halo that did not occupy the entire diameter of the Petri dish. The time in days spent to decolorize the whole Petri dish is given in parentheses;
• Control: growth of the fungus in the absence of dye.

Decolorization of Drimaren Brilliant Blue dye (0.002 g l-1) by Trametes villosa CCB176 grown in the static condition (_) and under shaking at 130 rpm (_). Decolorization was calculated considering the color of the non-inoculated control to be 100%. The bars indicate the standard deviation between duplicate experiments.

Decolorization of Drimaren Brilliant Blue dye by Trametes villosa CCB176 grown in the presence of different initial concentrations of the dye.

Decolorization was calculated considering the color of the non-inoculated control to be 100%. The bars indicate the standard deviation between duplicate experiments. The nitrogen concentration in the culture medium influenced the growth of T. villosa and P. sanguineus, with a greater biomass being obtained in the condition of nitrogen sufficiency (Fig. 3). However, decolorization of Drimaren Brilliant Blue by these fungi did not depend on the initial nitrogen concentration, with 100% decolorization being obtained after 7 days of incubation irrespective of the initial nitrogen concentration.

Degradation of the dye was confirmed based on its absorption spectrum. Therefore, in contrast to P. chrysosporium, Trametes versicolor, Phlebia brevispora and Lentinula edodes (3,5,11), T. villosa and P. sanguineus belong to a group of fungi whose ligninolytic systems are not regulated by nitrogen concentration, as also observed for Pleurotus ostreatus and Ceriporiopsis subvermispora (11,14,21). The presence of synthetic effluent did not influence the growth of T. villosa, but stimulated glucose consumption by this fungus after seven days of culture (Fig. 4). Approximately 90% decolorization was obtained after 21 days, as also confirmed by the absorption spectrum. The higher glucose consumption by the fungus in the presence of synthetic effluent might be evidence of increased metabolism due to the detoxification mechanism.

The presence of the effluent stimulated the growth of P. sanguineus, with an approximately 0.5 g higher biomass compared to control. Since glucose consumption by this fungus was not influenced by the presence of the effluent, the higher biomass observed might indicate the utilization of the dyes as a carbon source for growth. During the first days of culture, P. sanguineus decolorized the effluent more rapidly than T. villosa, with approximately 80% decolorization being observed after 10 days (Fig. 4). In general, significant decolorization rates of synthetic mixtures of reactive dyes have been reported for basidiomycetes. P. chrysosporium completely decolorized a synthetic effluent