Reactive dye bioaccumulation by fungus Aspergillus niger isolated from the effluent of sugar fabric-contaminated soil

Abstract

The present study dealt with the decolorization of textile dye Reactive Black-5 by actively growing mycelium of Aspergillus niger MT-1 in molasses medium. It was found that the fungus, which was isolated from the effluent of sugar fabric-contaminated soil, was capable of decolorizing the Reactive Black-5 dye in a wide range of temperature, shaking speed and pH values. The experiments also revealed that highest dye decolorization efficiency was achieved with cheap carbon (molasses sucrose) and nitrogen (ammonium chloride) sources. Under the optimized culture conditions, the complete decolorization (100%) of 0.1 g/L dye was achieved in 60 hours. The dominant mechanism of dye removal by the fungus was found to be probably bioaccumulation. Fungal growth in small uniform pellet form was found to be better for dye bioacumulation. Molass as carbon source increased dye bioaccumulation by stimulating the mycelial growth in small uniform pellet form. The maximum bioaccumulation efficiency of fungus for dye was 91% (0.273 g bioaccumulated dye) at an initial dye concentration of 0.3 g/L in 100 hours. It was shown for the first time in the present study that the effluent of sugar fabric-contaminated soil was a good source of microorganisms, being capable of decolorizing snythetic textile dyes.