Isolation and Identification of Fungi from Heavy Metal Contaminated Soil and the Evaluation of Their Heavy Metal Tolerance Level

ABSTRACTHeavy metal contamination in soil poses significant environmental and health challenges, often resulting from industrial, agricultural, and mining activities. This study aimed to investigate the potential of fungi for bioremediation in heavy metal-polluted environments. Soil samples were collected from a contaminated site at the Chemistry Department dumpsite of Usmanu Danfodiyo University, Sokoto, Nigeria. Fungi were isolated using serial dilution and cultured on potato dextrose agar (PDA). Isolated fungi were identified based on macroscopic and microscopic characteristics, revealing three species: Aspergillus niger, Aspergillus fumigatus, and Fusarium tricinctum. The heavy metal tolerance potential of these isolates were evaluated by exposing them to zinc and copper at 50ppm and 100ppm concentrations respectively. Results indicated that Aspergillus fumigatus exhibited the highest tolerance to both metals, with tolerance indices exceeding 0.73, suggesting its adaptability to metal-rich environments. In contrast, Fusarium tricinctum demonstrated the lowest tolerance, particularly to copper, with indices as low as 0.28 at higher concentrations. This research highlights the potential of fungal species, especially Aspergillus fumigatus, for use in bioremediation strategies targeting heavy metal-polluted soils, thereby contributing to advancing sustainable solutions for environmental restoration and groundwork for future studies focusing on field applications and molecular mechanisms of metal tolerance in fungi.