Introduction: Metal contamination represents a significant risk to ecosystems; it is therefore necessary to reduce the bioavailability, mobility and toxicity of these elements.
Objective: To isolate a filamentous fungus with the ability to tolerate metals.
Materials and methods: The fungus was isolated from soil with mining activity. The tolerance index and the minimum inhibitory concentration (MIC) of the fungus were determined at 1, 5, 10, 15 and 20 mM of the Cd, Hg, Pb, Ag, Cu, Zn and Cr metal salts.
Results and discussion: The isolated fungus was Aspergillus niger. It had average tolerance indices of 0.89, 1.03, 1.05, 0.94, 0.88, 0.87 and 1.27 at 1 mM of the Cd, Hg, Pb, Ag, Cu, Zn and Cr salts, respectively, after seven days of growth at 28 °C. The MIC of A. niger was found in a range of 5 to 10 mM of the Hg, Cu and Ag salts, and 15 to 20 mM of the Cd salt. The Pb, Zn and Cr salts did not inhibit the growth of the fungus with the highest concentration evaluated; that is, the MIC is greater than 20 mM.
Conclusión: Aspergillus niger has potential for the bioremediation of contaminants since it showed high tolerance to the metal salts.