Bioremoval capacity of recalcitrant azo dye Congo red by soil fungus Aspergillus arcoverdensis SSSIHL-01

Industrialization and urbanization have enormously contributed to water pollution. About 10 - 15% of all dyes used in processes in textile and other allied industries, have impacted aquatic ecosystem by discharge of several toxic chemicals and organic pollutants. Biological approach has always been advantageous over chemical and physical treatment methods of dye polluted wastewaters owing to cost effectiveness, mineralization of toxic chemicals and transforming them into harmless products. Present study was conducted to investigate the ability of soil fungus Aspergillus arcoverdensis SSSIHL-01 in the bioremoval of a common azo dye Congo red (CR). At the initial CR dye concentration of 100 mg/L, 3 g of wet fungal mycelia at 30 degrees C could decolorize about 95% and 98.6% of CR in dye solution and simulated wastewater respectively. Optical light microscopy through bright field and epi-fluorescence imaging modalities revealed the presence of CR dye in the fungal biomass by biosorption. Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) analysis revealed the amorphous nature of the fungus and its affinity to CR dye. UV-Vis and HPLC studies showed that decolorization occurred by both biosorption and biodegradation. Decolorization by live cells (98.61%) and dead cells (94.36%) illustrated that major part of dye removal was through biosorption, however 4.25% was by enzymolysis in living cells. Enzyme assay revealed that SSSIHL-01 produced about 22.73 +/- 2.02 U/L lignin peroxidase enzyme, indicating its possible role in CR degradation. Overall findings showed that Aspergillus arcoverdensis SSSIHL-01 could be explored as a potential bio-remediating agent in dyestuff wastewater treatment. This is the first report on evaluating the performance of the fungus Aspergillus arcoverdensis SSSIHL-01 on CR dye removal.