A Case Study of Fungal Geoactivities as Sustainable Approach for the Bioremediation of Synthetic Dyes and Metals from Wastewater

Efficient removal of synthetic dyes from wastewater is a challenging task. Chemical, physical, and biological approaches have been effective in eliminating dyes and reducing salt concentration in the wastewater. The study aimed to identify the most effective Aspergillus species for treating synthetic dyes and leachate samples in wastewater. Samples were collected from soil and leachate of the landfill, and isolation of fungi was achieved through dilution and cultivation on potato dextrose agar. According to morphological and microscopic characteristics, the isolated fungi were identified. Three types of synthetic dyes and a leachate sample were treated by five types of the isolated Aspergillus species for removing and reducing metals. UV spectrophotometer, scanning electron microscope, energy dispersive X-ray, and Fourier transform infrared spectroscopy were used for data analysis that were presented by statistical tools. Results revealed that Aspergillus terreus exhibited the highest decolorization efficiency, removing 98% of color from methyl orange, methyl violet, and rose bengal dyes after 14 days. While Aspergillus flavus demonstrated the best decolorization ability for leachate, achieving up to 94% color removal after 14 days. Energy dispersive X-ray analysis highlighted the binding of dye-related elements to fungal surfaces. Moreover, the interaction of Aspergillus species with landfill leachate reduced electrical conductivity and total dissolved solids significantly. Scanning electron microscopy images revealed mineral encrustations on fungal hyphae, suggesting metal immobilization and sequestration from the leachate. The findings offer insights into the mechanisms of fungal interaction with pollutants and provide valuable information for designing efficient water purification systems.