Heavy metal tolerance of filamentous fungal strains isolated from soil irrigated with industrial wastewater

Abstract

In the present study the tolerance level of different fungi (Aspergillus flavus, Aspergillus niger, Aspergillus versicolor, Scopulariopsis sp., Curvularia sp., Helminthosporium sp., Humicola grisea sp., Nannizzia sp., and Fusarium sp.) were investigated towards heavy metals which were isolated from contaminated peri-urban agricultural soils of Faisalabad. The concentration of heavy metals in soil is determined by using atomic absorption spectrophotometer. The degree of tolerance of fungi was measured by minimum inhibitory concentration in the presence of different concentrations of heavy metals (Cr and Pb) and compared to control sample. Tolerance analysis depicts that growth rate of fungal isolates decreased with increase in concentrations and few isolates are tolerant, some are moderately tolerant and some are sensitive towards metal concentrations of Cr and Pb. Most of the isolates were tolerant to metals. Among all tested fungal strains, few isolates of Aspergillus flavus and Aspergillus niger, Fusarium were tolerant to Cr and Pb. Thus these tolerant isolates can be used for the purpose of bioremediation in future.