Potential bacteria capable of remediating mercury contaminated soils

Abstract

Abstract Mercury content in ex-artisanal and small-scale gold mining areas in Cianjur District, Province of West Java, Indonesia was 7 to 36 mg L−1. It has exceeded the threshold value for industrial land. Bioremediation of mercury using mercury-resistant bacteria is attractive to remove mercury from the environment because it is more effective and less expensive. The objective of this study was to obtain potential bacteria capable of accumulating mercury to be used to remediate mercury contaminated soils in ex-gold mining areas. Potential bacteria isolates were characterized for their phenotypic and biochemical properties using the Biolog system. Thirty-two mercury-resistant bacteria were successfully isolated from the rhizosphere of Pityrogramma tartarea growing predominantly around tailings of ex-artisanal gold mining. After screening the presence of mercury, the three best isolates showing high resistances are Pseudomonas putida R2.13 and P. maculicola R4.27 that are capable to tolerate 180 mg L−1 mercury, and Enterobacter aerogenes R3.24 that is capable to survive at 170 mg L−1. Furthermore, the three bacteria also can fix atmospheric nitrogen and solubilize phosphate, but they cannot solubilize potassium. These indicate that P. maculicola R4.27, P. putida R2.13, and E. aerogenes R3.24 are potential as bioaccumulation agents on mercury-contaminated soils.