Biosorption of azo dyes by Aspergillus tamarii

The present study is an attempt to develop a suitable operational strategy for the biosorption of dyes, viz. Reactive Black (RB5), Reactive Violet (RV5) and Reactive Orange (R016) from synthetic solution by optimizing the initial pH, inoculum concentration, and initial dye concentration. A fungal strain capable of biosorption was isolated from local textile sludge. The isolate was characterized as Aspergillus tamarii through ribotyping. Studies on dye removal were carried out in batch culture. The batch studies, using growing cells of the fungus in sterile synthetic media containing dye, showed that the fungus was able to tolerate high dye concentration (upto 1000 ppm). The growth of the organism, and the removal of the three dyes by the organism were dependent on inoculum concentration (5-20%), dye concentration (100 ppm-1000 ppm), and pH (2.5 - 6.5). The maximum decolorization for R016 (93. 2%), RB5 (99. 9%) and RV5 (99.98%) was observed at pH 4.5 at inoculum concentrations of 20% for R016 and RB5, while only 5% for RV5. The surface morphology of the fungus before and after the dye sorption was established through scanning electron microscopy. Industry effluent was also treated to assess the reduction in chemical oxygen demand as well as dye concentration. The decolorization was found to be 40% without any amendment, and the reduction in COD was upto 23 ppm. This strain, therefore, has the potential to be used as the primary strain in treating the wastewaters.