Cellular and genetic mechanism of bacterial mercury resistance and their role in biogeochemistry and bioremediation

Mercury (Hg) is a highly toxic element that occurs at low concentrations in nature. However, various anthropogenic and natural sources contribute around 5000 to 8000 metric tons of Hg per year, rapidly deteriorating the environmental conditions. Mercury-resistant bacteria that possess the mer operon...

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Bibliographic Details
Published in:Journal of hazardous materials 2022-02, Vol.423 (Pt A), p.126985-126985, Article 126985
Main Authors: Priyadarshanee, Monika, Chatterjee, Shreosi, Rath, Sonalin, Dash, Hirak R., Das, Surajit
Format: Article
Language:English
Subjects:
Bacteria - genetics
Biodegradation, Environmental
Bioremediation
mer operon
Mercury
Mercury biogeochemistry
Mercury-resistant bacteria
Operon
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Summary:Mercury (Hg) is a highly toxic element that occurs at low concentrations in nature. However, various anthropogenic and natural sources contribute around 5000 to 8000 metric tons of Hg per year, rapidly deteriorating the environmental conditions. Mercury-resistant bacteria that possess the mer operon system have the potential for Hg bioremediation through volatilization from the contaminated milieus. Thus, bacterial mer operon plays a crucial role in Hg biogeochemistry and bioremediation by converting both reactive inorganic and organic forms of Hg to relatively inert, volatile, and monoatomic forms. Both the broad-spectrum and narrow-spectrum bacteria harbor many genes of mer operon with their unique definitive functions. The presence of mer genes or proteins can regulate the fate of Hg in the biogeochemical cycle in the environment. The efficiency of Hg transformation depends upon the nature and diversity of mer genes present in mercury-resistant bacteria. Additionally, the bacterial cellular mechanism of Hg resistance involves reduced Hg uptake, extracellular sequestration, and bioaccumulation. The presence of unique physiological properties in a specific group of mercury-resistant bacteria enhances their bioremediation capabilities. Many advanced biotechnological tools also can improve the bioremediation efficiency of mercury-resistant bacteria to achieve Hg bioremediation. [Display omitted] •Hg is a global pollutant, which has adverse effects on human health.•Mercury-resistant bacteria harbour genes for Hg resistance and detoxification.•mer operon system is diversified in various bacteria.•Biogeochemical cycling of Hg depends upon its chemical speciation.•Transgenic bacteria and plants with mer determinants potentially remove Hg.
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2021.126985