Use of microorganism for decolorization of textile dyes

Synthetic dyes are released into the environment in industrial effluents from textiles and dyestuff industries. The discharge of those colored wastewater into rivers and lakes leads to reduction of sunlight penetration in natural water bodies which in turn decreases both photosynthetic activity and dissolved oxygen concentration. Some dyes and wastewaters are also toxic and genotoxic. Moreover, textile dyes are also resistant to microbial degradation. White rot fungi can degrade wide variety of structually diverse pollutants. In this study, we tested the decolorizing activity of white rot fungi. The effects of various conditions such as initial pH, dye concentrations, amount of pellet, temperture and agitation on decolorizing activity of Funalia trogii were investigated. These except initial pH were all found to be important for dye decolorizing activity of F. trogii. The longevity of the decolorization activity of F. trogii pellets was also investigated in repeated batch mode. At low dye concentrations such as 13-132 mg/1, the decolorization performance of the pellets remained high and stable for 5 days. High decolorization efficiency of nearly 96 % was obtained within the first 3 days of repeated batch operation for the dye concentration of 264 mg/1. However, decolorization efficiency decreased at the end of 5 days of operation. Variations in the amount of pellet increased the decolorization % and stability of pellets. The decolorization of the dye involved adsorption of the dye compound by fungal pellets at initial stage, followed by the biodegradation through microbial metabolism. MnSÛ4, NH4CI, glucose and cheese whey were added into test media for incerasing efficiency and longevity of decolorization activity of F. trogii. When glucose and cheese whey were used, high and stable decolorization efficiency was obtained within the 10 days of repeated batch operation (initial dye concentration was 264 mg/1). The decolorizing abilities of white rot fungi other than F. trogii were also tested. KEYWORDS: Textile dye, dye, white rot fungi, Funalia trogii, decolorizatioi İ iii