DECOLORIZATION OF DIFFERENT DYES BY FILAMENTOUS FUNGI ISOLATED FROM TEXTILE EFFLUENT

There is an increase of the environmental contamination caused by a large amount of dyes discharged in the liquid effluents by textile industry. Textile effluent consists of a high organic load, chemicals, suspended and dissolved solids, heavy metals, and an strong coloration due to dyes use during dyeing processes. Bioremediation methods are efficient for an wide variety of toxic compounds, present lower costs in the application and generate products that do not damage the environment. There is an wide field of research on the enzyme performance from the fungal ligninolytic system in bioremediation processes. Several filamentous fungi are able to mineralize pollutant compounds through ligninolytic enzymes production, which are also responsible for the decolorization and degradation of many different dyes. Thus, the aim of the present study was to investigate the ability of filamentous fungi isolated from a treatment plant of the textile industry in decolorize dyes used in textile industry. Sixty isolates were analyzed. Screening for dyes decolorization was performed by culturing fungal strains in PDA medium (4 g potato infusion; 20 g dextrose; 15 g agar; per liter) added 500 and 1000 ppm of RBBR (Remazol Brilliant Blue R) and Tingecor Black 31 – TP31 during 21 days at 28 ºC. Positive results were visualized on Petri dishes containing dyes by the formation of decolorization halo (colorless) around the colony. Eight isolates showed decolorization halo. The isolate ITF12 (not identified) was the best producer of colorless halo on plates with RBBR (500 ppm – 0.8 cm) and TP31 (500 ppm – 0.3 cm and 1000 ppm – 0.2 cm). Two isolates from genera Aspergillus (ITF22 and ITF30) showed decolorization halo on plates with RBBR (0.1 cm for both). The isolate ITF13 (Penicillium) showed decolorization halo on plates with TP31 (500 ppm – 0.5 cm and 1000 ppm – 0.3 cm). Four isolates (ITF 34 – Penicillium; ITF 39 – not identified; ITF 44 - not identified; and ITF 60 - not identified), showed colorless halo only on plates with TP31 (0.5 cm, 0.3 cm, 0.3 cm and 0.5 cm), respectively. Results from the present work showed that filamentous fungi isolated from textile effluent may be applied on bioremediation processes to perform dyes decolorization.