Volatilization of Mercury under Acidic Conditions from Mercury-polluted Soil by a Mercury-resistant Acidithiobacillus ferrooxidans SUG 2-2

Mercury Pollution and Bioremediation—A Case Study on Biosorption by a Mercury-Resistant Marine Bacterium

“…Microbial volatilization mechanisms without the involvement of mer operon-encoded mercuric reductase enzyme have been discovered (Takeuchi and Sugio, 2006;Wiatrowski et al, 2006;Al Mailem et al, 2011). The most remarkable has been the discovery of a constitutive mechanism for volatilization of mercury in dissimilatory metal-reducing bacteria (e.g., Shewanella oneidensis MR-1, Geobacter sulfurreducens PCA, and Geobacter metallireducens GS-15), which is not linked to reduction by the MerA and is dependent on iron (Wiatrowski et al, 2006).…”

Volatilization of Mercury by an Iron Oxidation Enzyme System in a Highly Mercury-resistantAcidithiobacillus ferrooxidansStrain MON-1

“…10) Strain SUG 2-2 has an ability to volatilize metal mercury from mercury-polluted wastewater and soil under acidic conditions in the presence of ferrous iron. [28][29][30] We recently showed that A. ferrooxidans SUG 2-2 has not only NADPH-dependent mercury reductase activity but also Fe 2＋ -dependent mercury reductase activity in the cells 10) and cytochrome c oxidase puriˆed from strain SUG 2-2 volatilizes mercury in the presence of Fe 2＋ . 28) In this study, a highly mercury-resistant strain, A. ferrooxidans MON-1 was isolated from a culture of a moderately mercury-resistant strain, A. ferrooxidans SUG 2-2, by successive cultivation and isolation of the latter strain in a Fe 2＋ medium with increased amounts of Hg 2＋ from 6 mM to 20 mM.…”

Biodegradation: Involved Microorganisms and Genetically Engineered Microorganisms

“…For example, Mercury, Hg(II) can be biomethylated by a number of different bacterial species Alcaligenes faecalis, Bacillus pumilus, Bacillus sp., P. aeruginosa and Brevibacterium iodinium to gaseous methyl mercury [46]. In addition to redox conversions and methylation reactions, acidophilic iron bacteria like Acidithiobacillus ferrooxidans [47] and sulfur oxidizing bacteria [48] are able to leach high concentrations of As, Cd, Cu, Co and Zn from contaminated soils. On the other hand metals can be precipitated as insoluble sulfides indirectly by the metabolic activity of sulphate reducing bacteria [48].…”