Methylmercury uptake and degradation by methanotrophs

Xia Lu, Wenyu Gu, Linduo Zhao, Muhammad Farhan Ul Haque, Alan A. DiSpirito, Jeremy D. Semrau, Baohua Gu

Research output: Contribution to journalArticle

Abstract

Methylmercury (CH3Hg+) is a potent neurotoxin produced by certain anaerobic microorganisms in natural environments. Although numerous studies have characterized the basis of mercury (Hg) methylation, no studies have examined CH3Hg+ degradation by methanotrophs, despite their ubiquitous presence in the environment. We report that some methanotrophs, such as Methylosinus trichosporium OB3b, can take up and degrade CH3Hg+ rapidly, whereas others, such as Methylococcus capsulatus Bath, can take up but not degrade CH3Hg+. Demethylation by M. trichosporium OB3b increases with increasing CH3Hg+ concentrations but was abolished in mutants deficient in the synthesis of methanobactin, ametal-binding compound used by some methanotrophs, such as M. trichosporium OB3b. Furthermore, addition of methanol (>5 mM) as a competing one-carbon (C1) substrate inhibits demethylation, suggesting that CH3Hg+ degradation bymethanotrophs may involve an initial bonding of CH3Hg+ by methanobactin followed by cleavage of the C-Hg bond in CH3Hg+ by themethanol dehydrogenase. This new demethylation pathway bymethanotrophs indicates possible broader involvement of C1-metabolizing aerobes in the degradation and cycling of toxic CH3Hg+ in the environment.

Original languageEnglish (US)
Article numbere1700041
JournalScience Advances
Volume3
Issue number5
DOIs
StatePublished - May 2017
Externally publishedYes

ASJC Scopus subject areas

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    Lu, X., Gu, W., Zhao, L., Ul Haque, M. F., DiSpirito, A. A., Semrau, J. D., & Gu, B. (2017). Methylmercury uptake and degradation by methanotrophs. Science Advances, 3(5), [e1700041]. https://doi.org/10.1126/sciadv.1700041