Thiol-facilitated cell export and desorption of methylmercury by anaerobic bacteria
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lanzhou Univ. (China)
Neurotoxic methylmercury (MeHg), formed by anaerobic bacteria, is shown to be rapidly excreted from the cell, but the mechanism of this process is unclear. Using both Geobacter sulfurreducens PCA and Desulfovibrio desulfuricans ND132 strains, we investigated the factors affecting export and distribution of MeHg in mercury methylation and MeHg sorption-desorption assays. Thiols, such as cysteine, were found to greatly facilitate desorption and export of MeHg, particularly by PCA cells. However, in cysteine-free assays (4 h) >90% of the synthesized MeHg was associated with PCA, among which ~73% was sorbed on the cell surface and 19% remained inside the cells. In comparison, a majority of the MeHg (70%) was exported by ND132, leaving ~20% of the MeHg sorbed on the surface and 10% inside the cells. When MeHg was added directly to the cell suspensions, ND132 adsorbed much lower MeHg but took up more MeHg inside cells than PCA did. These results demonstrate that MeHg export is bacteria strain-specific, time dependent, and is influenced by thiols, implicating important roles of ligand complexation in facilitating MeHg production and mobilization in the environment.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1214516
- Journal Information:
- Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 9 Vol. 2; ISSN 0013-936X
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Enhanced Production of Bioethanol by Fermentation of Autohydrolyzed and C4mimOAc-Treated Sugarcane Bagasse Employing Various Yeast Strains