Sunday, May 4, 2008
2-33

Volatilization of mercury in coal via the mercury reductase operon in Acidithiobacillus ferrooxidans, ATCC 53993

Abhijeet P. Borole, Biosciences Division, Oak Ridge National Laboratory, 1-Bethel Valley Road, Bldg 1520, Rm 217, Oak Ridge, TN 37831

The mercury reductase genes in the organism Acidithiobacillus ferrooxidans, strain ATCC 53993, were identified using the genome sequence completed in 2006. The strain was found to be capable of reduction of Hg+2 to elemental mercury and tolerant to high concentrations of Hg+2. The mercury reductase operon was constructed by identifying homologous genes involved in known mercury transport and conversion pathways. The abilty of the strain to volatilize mercury was applied to removal of mercury from coal using a single step biological process. The process included dissolution of pyritic minerals from the coal, release of mercuric species from the coal into the aqueous phase, volatilization of the Hg+2 to elemental mercury, followed by its removal from the coal slurry by air sparging.