BIOSORPTION AND METAL TOLERANCE POTENTIAL OF FILAMENTOUS FUNGI ISOLATED FROM METAL POLLUTED ECOSYSTEM

Microorganisms play a significant role in bioremediation of heavy metal contaminated soil and water ecosystem. Heavy metal analysis of soil receiving continuous (>50 years) application of municipal sewage showed two- to ten -fold accumulation of certain heavy metals. In the present study metal-resistant fungi were isolated from municipal sewage contaminated soil viz., Aspergillus niger, Phanerochaete chrysosporium and Trichoderma viride. The laboratory study was conducted to determine the Minimum Inhibitory Concentrations (MICs) of Ni and Cr for isolated fungal cultures. The MICs ranged from 75 to 100 mg L -1 for Cr, followed by Ni (50 to 100 mg L -1), depending on the isolate. These isolates were tested for their metal biosorption potential for Cr and Ni in vitro condition. Biosorption experiments were conducted with initial metal concentrations of 25, 50, 75 and 100 mg L-1 with a contact time of 48 h and wet fungal biomass (6 mm diameter) at 25oC. Maximum biosorption of Cr and Ni ions was found at 100 mg L-1. Among the fungi P. chrysosporium accumulated 64.25 per cent of Cr and 57 per cent of Ni than other fungi. The purpose of this study is to explore the possibilities of these fungal biomasses for heavy metal remediation.