Fungal biosorption of the heavy metals chromium(VI) and nickel from industrial effluent-contaminated soil

Abstract

Heavy metals are ubiquitous contaminants that have accompanied man since the earliest ancient times, and unlike other environmental pollutants, they are chemical elements that man does not create or destroy. In the present study, the aim was to determine the biosorption potential of heavy metal-tolerant fungi that were isolated from compost soil samples contaminated by industrial effluents. The isolation was performed on potato dextrose agar (PDA) media supplemented with heavy metals. Chromium-Cr(VI) and nickel-Ni. The most dominant fungal species were found to be Penicillium spp. This fungus was screened for its ability to tolerate heavy metals by the plate diffusion and broth method and was highly tolerant to fungal species. The fungi were assessed for their ability to remove heavy metals from the culture media, and the culture conditions for the fungus were experimentally optimized. The isolated Penicillium species was found to show maximum growth at 35°C with media pH 6 for an incubation period of 168 hours. The isolate was able to tolerate 60-70 ppm concentrations of heavy metals under normal conditions. The ability of the isolate to take up metal was very effective, as after 96 hrs of incubation, it was capable of removing approximately 93.8% of Cr(VI) and 95.6% of Ni from the culture media, and complete uptake was observed after a 144 hr incubation period. The molecular characterization revealed the only isolate to be Penicillium rubens (Accession no. LC536286). The morphological characteristics of this fungus make it capable of biosorption of heavy metals, imparting its bioremediation potential and economic importance.