Characterization of three Pb-resistant fungi and their potential Pb 2þ ions adsorption capacities

Abstract

Bioremediation is preferred in heavy metal remediation, and the high-performance microbe is of prime importance. In the present research, three Pb-resistant microbes were isolated and growth characteristics and adsorption capacities were evaluated. The results showed that R. oryzae SD-1, T. asperellum SD-5, and M. irregularis SD-8 can grow well under 100 mg L 1 Pb 2þ ions stress. There is a higher minimum inhibitory concentration (MIC) of Pb but lower MICs of Cd and Zn in T. asperellum SD-5. However, there were similar MICs of Cu among the three microbes. R. oryzae SD-1 exhibited a higher adsorption capacity and removal rate relative to the other two microbes under various Pb 2þ ion levels. The Langmuir equation was fitted for the adsorption capacity of T. asperellum SD-5 and M. irregularis SD-8, and their maximum adsorption capacities were approximately 456.62 mg g 1 and 93.62 mg g 1 . Moreover, the Elovich equation and the double constant equation can describe the adsorption process of Pb 2þ ions in Pb-resistant microbes well. The strongest adsorption capacity under lower Pb 2þ ion level was observed in M. irregularis SD-8, while the strongest adsorption capacities under higher Pb 2þ ion levels were seen in R. oryzae SD-1 and T. asperellum SD-5. Therefore, three novel Pb-resistant microbes may be used as efficient, easily cultivated materials for Pb-contaminated soil remediation.