Bioremediation of wastewater containing mercury using three newly isolated bacterial strains

To successfully clean and recycle heavy metal-contaminated wastewater, we developed a fast, simple, low-cost, and efficient bioremediation method to eliminate mercury (Hg) pollution. We isolated three bacterial strains with strong Hg tolerance and reduction capacities from the polluted waters of the Yellow River. These bacterial strains mainly reduced Hg2+ by the mer operon. The bacterial strains had the best treatment effect on Hg-contaminated wastewater when mixed in equal proportions. Under the optimum growth conditions of the bacterial strains, it would take about 60 L of the three strains in the same proportion in a cultured solution to treat 1 ton of wastewater containing 10 mg/L Hg2+. After 48 h of treatment, the concentration of Hg2+ in the wastewater could reach the national standard (Hg2+ <0.05 mg/L). The bacterial strains also exhibited tolerance and transformational abilities for Pb2+, Cr6+, As5+, and Cd2+, indicating that these bacteria could be utilized in more complex heavy metal-polluted environments. This work revealed a new method for the bioremediation of heavy metal-polluted wastewater. (C) 2021 Elsevier Ltd. All rights reserved.