RESUMO
In the present work, a strain of the basidiomycete fungus Trametes polyzona was used to decolorize the Amaranth dye. The decolorization was carried out in an Airlift reactor with three flow regimes: 1, 2, and 3 vvm. The results showed that the decolorization was a function of the flow regime. The decolorization times for the regimes of 1, 2, and 3 vvm were 30, 25, and 19 days, respectively. The COD (Chemical Oxygen Demand) decreased from 1600 to 72 mg COD/L. The enzymatic activity kinetics of laccase (Lcc), lignin peroxidase (LiP), and manganese peroxidase (MnP) were determined. In all the treatments, the enzyme LiP was expressed during the first 6 days, at which point 80% decolorization was observed, whereas Lcc and MnP enzymes were produced from day 6 until the end of the decolorization process. The effluent generated showed no inhibitory effects on the growth of the algae Nannochloropsis salina. T. polyzona showed great versatility in the decolorization of synthetic effluents containing the Amaranth dye, and the fungus was able to use this dye as its only carbon source starting at the beginning of the process. LiP was the enzyme that contributed the most to the decolorization process, and on average, 95% decreases in color and the COD were observed.
RESUMO
A biodecolorization model that considers the simultaneous mechanism of biosorption and biodegradation of a synthetic dye by immobilized white-rot fungus Trametes subectypus B32 in a fixed bed bioreactor was developed. The model parameters (biokinetic, biosorption and macroscopic transport) were determined by independent experiments. The biodecolorization model was used to determine the effect of variables such as immobilized biomass content, volumetric flow of wastewater, dye feeding concentration and initial dye concentration. By means of the model was possible to predict in the steady state, the limits of immobilized T. subectypus to biodecolorize polluted influent, being the model predictions similar in extent to previous reports. A dimensionless module of biosorption-bioreaction (Ï=q(max)v(z)/r(max)L) was proposed to be used like criterion whenever one of the two mechanisms controls the biodecolorization. The model could be used for the designing and scaling up of fixed bed bioreactors with immobilized white-rot fungi for the biodecolorization process.