AVALIAÇÃO DO POTENCIAL DE DESCOLORAÇÃO E DE DETOXIFICAÇÃO DE CORANTES TÊXTEIS POR LACASE DE PLEUROTUS SAJOR-CAJU.

Wastewater is an environmental constraint for the development of the textile industry, since sometimes due to inappropriate management and/or ineffective treatment, it leads to contamination of biota. One of the main characteristics of textile wastes is the high amount of dye which, during the production process did not adhere to the fiber, thus appearing in the final waste. These wastes, when released into the aquatic environment reduce the availability of light, photosynthesis, as well as other environmental problems. Furthermore, these compounds are mostly toxic, even in small concentrations. Enzymes produced by Pleurotus sajor-caju are reported as efficient in color removal, dye degradation and detoxification of textile wastes. The objective of this study was to evaluate the ability of Pleurotus sajor-caju crude enzyme broth to remove color and reduce the toxicity of solutions containing Red 50 and Blue 56 dyes (100 mg L-1). For such, production of the enzyme broth was carried out in a bioreactor (working volume of 4 L), which was used directly on the dye solution, diluted in water (1:1) and diluted in ABTS (2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)) (1:1). Ecotoxicological tests were performed using the freshwater crustacean Daphnia magna. Higher efficiency in color removal by the crude enzymatic broth of P. sajor-caju diluted in ABTS solution was observed (removal rates equal to 1.3 and 1.9x10-2 mg U-1 h-1, for dyes Red 50 and Blue 56, respectively). The laccase enzyme was quantified in the enzyme broth (115 U L-1) and maintained its activity 100% throughout all assays. A statistically significant reduction in toxicity was observed for Blue 56 dye. Red 50 dye remained toxic even after the enzymatic treatment, suggesting the need for a longer reaction time for this dye. The P. sajorcaju crude enzyme broth proved to be effective and promising for use in textile wastewater treatment plants. [ABSTRACT FROM AUTHOR]