Identification and characterization of cadmium resistant fungus isolated from contaminated site and its potential for bioremediation

Abstract This study investigates the tolerance potential of different species of indigenous fungi that have been isolated from different contaminated sites. The highly resistant organism was optimized under different processed conditions. 11 fungal isolates (F1-F11) have been isolated from samples contaminated with Cd in potato agar plates amended with various concentration ranging from 100-500ppm of Cd(II). The fungi which were found resistant to Cd(II) in primary screening were subjected to secondary screening. Among these strains, isolate F2 was found to be the most tolerant against the Cd(II) at higher concentration with removal percentage of 74.76 ± 0.24 and uptake of 5.02 ± 1.21mg/g. The strain (FS2) was identified as Aspergillus fumigatus based on internal transcribed spacer DNA region (ITS). Among the two isotherm tested, correlation coefficients (R2) of Cd(II) by A. fumigatus were found to be greater for Langmuir isotherm than Freundlich isotherm. Treated and untreated biosorbent were characterized by FTIR spectral analysis and SEM micrograph to study the nature of the biosorbent both prior to and after the removal of Cd(II) ions. It is envisaged that this metal tolerance trait exhibited by this fungal strain may indicate its potentials as successful mediator for bio-remediative clean-up of heavy metal polluted environments.