RESUMO
A three-level Box-Behnken factorial design with three factors and the Response Surface Methodology were used to optimise the colour removal of the reactive textile dye, Colour Index (C.I.) reactive red 180, by commercial laccase. A mathematical model was developed to study the effect of temperature, pH, enzyme concentration and their interactions on the decolourisation. Enzyme concentration and pH as well as their interaction were the principal factors that affected the decolourisation. The dye degradation was independent of temperature. The model estimated that the highest decolourisation (> 92%) was obtained for 27 degrees C, pH 7.5 and 85 U l(-1). This predicted value was experimentally validated, obtaining dye colour removal (540 nm) of 93 +/- 1.5%.
Assuntos
Corantes/metabolismo , Lacase/metabolismo , Indústria Têxtil , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Corantes/química , Corantes/isolamento & purificação , Relação Dose-Resposta a Droga , Ativação Enzimática , Análise Fatorial , Concentração de Íons de Hidrogênio , Lacase/química , Matemática , Modelos Químicos , Valor Preditivo dos Testes , Temperatura , Poluentes Químicos da Água/químicaRESUMO
Experimental design and response surface methodologies were applied to optimize laccase production by Trametes versicolor in a bioreactor. The effects of three factors, initial glucose concentration (0 and 9 g/L), agitation (100 and 180 rpm), and pH (3.0 and 5.0), were evaluated to identify the significant effects and its interactions in the laccase production. The pH of the medium was found to be the most important factor, followed by initial glucose concentration and the interaction of both factors. Agitation did not seem to play an important role in laccase production, nor did the interaction agitation x medium pH and agitation x initial glucose concentration. Response surface analysis showed that an initial glucose concentration of 11 g/L and pH controlled at 5.2 were the optimal conditions for laccase production by T. versicolor. Under these conditions, the predicted value for laccase activity was >10,000 U/L, which is in good agreement with the laccase activity obtained experimentally (11,403 U/L). In addition, a mathematical model for the bioprocess was developed. It is shown that it provides a good description of the experimental profile observed, and that it is capable of predicting biomass growth based on secondary process variables.
Assuntos
Algoritmos , Basidiomycota/enzimologia , Basidiomycota/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Lacase/biossíntese , Modelos Biológicos , Proliferação de Células , Simulação por Computador , Modelos Estatísticos , Controle de QualidadeRESUMO
The white rot fungus Trametes versicolor was applied to the decolourisation of three synthetic textile dyes in the presence and absence of glucose. Different initial dye concentrations were tested and approximately 97% decolourisation was achieved. It was found that fungal metabolism induced by the glucose as well as the pH play an important role in the decolourisation process. This treatment was also applied to a real wastewater from a textile industry-dyeing sector leading to 92% decolourisation.
