Abstract：The extensive exploitation and usage of lead resources have caused serious environmental pollution problems currently. Bioremediation of Pb2+ contaminated water and soil environments using microbes is regarded as a promising technology due to the advantages of its cost-effective, easy operation and environmental-friendly properties. In order to understand Pb2+ biosorption characterization of microbes, an indigenous lead-resistant bacterium-Arthrobacter sp. 12-1(GenBank No. KM362724) was isolated from lead-zinc mine tailing dam, and the process and mechanism of Pb2+ biosorption by Arthrobacter sp. 12-1 were furtherly investigated in this study. Study on the growth of Arthrobacter sp. 12-1 in LB medium containing different concentration of Pb2+ suggested that the highest Pb2+ tolerant concentration of Arthrobacter sp. 12-1 was 800 mg/L. In water solution, 105 mg/L of Pb2+ could be reduced to 2.17 mg/L by Arthrobacter sp. 12-1 within 24 h with biosorption rate of 97.93%. Microscopic investigation (atomic force microscopy and scanning electronic microscopy) combined with energy dispersive X-ray spectroscopy analysis showed that lead containing mineral was formed on the surface of cell after Pb2+ sorption by Arthrobacter sp. 12-1. Further fourier transform infrared (FT-IR) analysis revealed that carboxyl, amide and phosphate groups of Arthrobacter sp. 12-1 might be involved in Pb2+ biosorption process. The results demonstrated that the Arthrobacter sp. 12-1 isolated from lead-zinc mine tailing dam had strong ability of Pb2+ resistance and biosorption, indicating an attractive prospect of practical applications in bioremediation Pb2+ contaminated water and soil environments. The present work provides much fundamental information for help in constructing feasible strategies for Pb2+ bioremediation in the environment.
