scholarly journals Effect of Exogenous and Endogenous Sulfide on The Production and The Export of Methylmercury by Sulfate Reducing Bacteria

2021 ◽  
Author(s):  
Sophie Barrouilhet ◽  
Mathilde Monperrus ◽  
Emmanuel Tessier ◽  
Bahia Khalfaoui-Hassani ◽  
Remy Guyoneaud ◽  
...  
Keyword(s):  
Health Concern ◽  
Sulfide Concentration ◽  
Natural Environments ◽  
Strong Positive Correlation ◽  
Extracellular Medium ◽  
Sulfate Reducing ◽  
Global Pollutant ◽  
Reducing Bacteria ◽  
The Impact ◽  
Sulfur Containing

Abstract Mercury (Hg) is a global pollutant of environmental and health concern; its methylated form, methylmercury (MeHg) is a potent neurotoxin. Sulfur-containing molecules play a role in MeHg production by microorganisms. While sulfides are considered to limit Hg methylation, sulfate and cysteine were shown to favor this process. However, these two forms can be endogenously converted by microorganisms into sulfide. Here, we explore the effect of sulfide (produced by the cell or supplied exogenously) on Hg methylation. For this purpose, Pseudodesulfovibrio hydrargyri BerOc1 was cultivated in non-sulfidogenic conditions with addition of cysteine and sulfide as well as in sulfidogenic conditions. We report that Hg methylation depends on sulfide concentration in the culture rather than on the initial form of sulfur (cysteine, sulfide or sulfate) added, and was independent of hgcA expression. Interestingly, MeHg production was maximal at 0.1-0.5 mM of sulfides. Besides, a strong positive correlation between MeHg in the extracellular medium and the increase of sulfide concentrations was observed, suggesting a facilitated MeHg export with sulfide and/or higher desorption from the cell. We demonstrate that sulfides (exogenous or endogenous) play a key role in controlling mercury methylation, and should be considered when investigating the impact of Hg on natural environments.

scholarly journals Integrative analysis of <i>Geobacter</i> spp. and sulfate-reducing bacteria during uranium bioremediation

2012 ◽  
Vol 9 (3) ◽  
pp. 1033-1040 ◽  
Author(s):  
M. Barlett ◽  
K. Zhuang ◽  
R. Mahadevan ◽  
D. Lovley
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Field Trials ◽  
Second Phase ◽  
Sulfate Reducing ◽  
Organic Electron ◽  
Poor Understanding ◽  
Key Factor ◽  
Reducing Bacteria ◽  
The Impact

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

scholarly journals Growth of Anaerobic Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in a High-Pressure Membrane Capsule Bioreactor

2014 ◽  
Vol 81 (4) ◽  
pp. 1286-1296 ◽  
Author(s):  
Peer H. A. Timmers ◽  
Jarno Gieteling ◽  
H. C. Aura Widjaja-Greefkes ◽  
Caroline M. Plugge ◽  
Alfons J. M. Stams ◽  
...  
Keyword(s):  
High Pressure ◽  
Partial Pressure ◽  
Methane Oxidation ◽  
Ambient Pressure ◽  
Sulfate Reducing Bacteria ◽  
Sulfide Concentration ◽  
Methane Pressure ◽  
Sulfate Reducing ◽  
Oxidation Rates ◽  
Reducing Bacteria

ABSTRACTCommunities of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) grow slowly, which limits the ability to perform physiological studies. High methane partial pressure was previously successfully applied to stimulate growth, but it is not clear how different ANME subtypes and associated SRB are affected by it. Here, we report on the growth of ANME-SRB in a membrane capsule bioreactor inoculated with Eckernförde Bay sediment that combines high-pressure incubation (10.1 MPa methane) and thorough mixing (100 rpm) with complete cell retention by a 0.2-μm-pore-size membrane. The results were compared to previously obtained data from an ambient-pressure (0.101 MPa methane) bioreactor inoculated with the same sediment. The rates of oxidation of labeled methane were not higher at 10.1 MPa, likely because measurements were done at ambient pressure. The subtype ANME-2a/b was abundant in both reactors, but subtype ANME-2c was enriched only at 10.1 MPa. SRB at 10.1 MPa mainly belonged to the SEEP-SRB2 and Eel-1 groups and theDesulfuromonadalesand not to the typically found SEEP-SRB1 group. The increase of ANME-2a/b occurred in parallel with the increase of SEEP-SRB2, which was previously found to be associated only with ANME-2c. Our results imply that the syntrophic association is flexible and that methane pressure and sulfide concentration influence the growth of different ANME-SRB consortia. We also studied the effect of elevated methane pressure on methane production and oxidation by a mixture of methanogenic and sulfate-reducing sludge. Here, methane oxidation rates decreased and were not coupled to sulfide production, indicating trace methane oxidation during net methanogenesis and not anaerobic methane oxidation, even at a high methane partial pressure.

scholarly journals Aspects of Bioavailability of Mercury for Methylation in Pure Cultures of Desulfobulbus propionicus (1pr3)

2001 ◽  
Vol 67 (1) ◽  
pp. 51-58 ◽  
Author(s):  
J. M. Benoit ◽  
C. C. Gilmour ◽  
R. P. Mason
Keyword(s):  
Time Course ◽  
Sulfide Concentration ◽  
Desulfobulbus Propionicus ◽  
Methylation Rate ◽  
Sulfate Reducing ◽  
Phase Culture ◽  
Pure Cultures ◽  
Culture Growth ◽  
Reducing Bacteria ◽  
The Relationship

ABSTRACT We have previously hypothesized that sulfide inhibits Hg methylation by decreasing its bioavailability to sulfate-reducing bacteria (SRB), the important methylators of Hg in natural sediments. With a view to designing a bioassay to test this hypothesis, we investigated a number of aspects of Hg methylation by the SRBDesulfobulbus propionicus, including (i) the relationship between cell density and methylmercury (MeHg) production, (ii) the time course of Hg methylation relative to growth stage, (iii) changes in the bioavailability of an added inorganic Hg (HgI) spike over time, and (iv) the dependence of methylation on the concentration of dissolved HgI present in the culture. We then tested the effect of sulfide on MeHg production by this microorganism. These experiments demonstrated that under conditions of equal bioavailability, per-cell MeHg production was constant through log-phase culture growth. However, the methylation rate of a new Hg spike dramatically decreased after the first 5 h. This result was seen whether methylation rate was expressed as a fraction of the total added Hg or the filtered HgI concentration, which suggests that Hg bioavailability decreased through both changes in Hg complexation and formation of solid phases. At low sulfide concentration, MeHg production was linearly related to the concentration of filtered HgI. The methylation of filtered HgI decreased about fourfold as sulfide concentration was increased from 10−6 to 10−3 M. This decline is consistent with a decrease in the bioavailability of HgI, possibly due to a decline in the dissolved neutral complex, HgS0.

scholarly journals Damming Induced Natural Attenuation of Hydrothermal Waters by Runoff Freshwater Dilution and Sediment Biogeochemical Transformations (Sochagota Lake, Colombia)

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3445
Author(s):  
Gabriel Ricardo Cifuentes ◽  
Rosario Jiménez-Espinosa ◽  
Claudia Patricia Quevedo ◽  
Juan Jiménez-Millán
Keyword(s):  
Natural Attenuation ◽  
Volcanic Area ◽  
Iron Sulfides ◽  
Sulfate Reducing ◽  
High Concentrations ◽  
Biogeochemical Transformations ◽  
Reducing Bacteria ◽  
The Impact ◽  
Basin Area ◽  
Mixed Water

The volcanic area of the Paipa system (Boyacá, Colombia) contains a magmatic heat source and deep fractures that help the flow of hot and highly mineralized waters, which are further combined with cold superficial inputs. This mixed water recharges the Salitre River and downstream feeding Sochagota Lake. The incoming water can contribute to substantial increases in hydrothermal SO42−-Na water in the water of the Salitre River basin area, raising the salinity. An additional hydrogeochemical process occurs in the mix with cold Fe-rich water from alluvial and surficial aquifers. This salinized Fe-rich water feeds the Sochagota Lake, although the impact of freshwaters from rain on the hydrochemistry of the Sochagota Lake is significant. A series of hydrogeochemical, biogeochemical, and mineralogical processes occur inside the lake. The aim of this work was to study the influence of damming in the Sochagota Lake, which acts as a natural attenuation of contaminants such as high concentrations of metals and salty elements coming from the Salitre River. Damming in the Sochagota Lake is considered to be an effective strategy for attenuating highly mineralized waters. The concentrations of dissolved elements were attenuated significantly. Dilution by rainfall runoff and precipitation of iron sulfides mediated by sulfate-reducing bacteria in deposits rich in organic material were the main processes involved in the attenuation of concentrations of SO42−, Fe, As Cu, and Co in the lake water. Furthermore, the K-consuming illitization processes occurring in the sediments could favor the decrease in K and Al.

scholarly journals Integrative analysis of the interactions between <i>Geobacter</i> spp. and sulfate-reducing bacteria during uranium bioremediation

2011 ◽  
Vol 8 (6) ◽  
pp. 11337-11357 ◽  
Author(s):  
M. Barlett ◽  
K. Zhuang ◽  
R. Mahadevan ◽  
D. R. Lovley
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Field Trials ◽  
Second Phase ◽  
Sulfate Reducing ◽  
Organic Electron ◽  
Poor Understanding ◽  
Key Factor ◽  
Reducing Bacteria ◽  
The Impact

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

Sulfate-reducing bacteria in leachate-polluted aquifers along the shore of the East China Sea

2009 ◽  
Vol 55 (7) ◽  
pp. 818-828 ◽  
Author(s):  
Xiu-Juan Wu ◽  
Jian-Liang Pan ◽  
Xiang-Long Liu ◽  
Jing Tan ◽  
Dao-Tang Li ◽  
...  
Keyword(s):  
East China Sea ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pcr Amplification ◽  
Sulfate Reducing Bacteria ◽  
East China ◽  
The East China Sea ◽  
China Sea ◽  
Sulfate Reducing ◽  
Reducing Bacteria ◽  
The Impact

The diversity of sulfate-reducing bacteria (SRB) in the aquifer underlying the Laogang Landfill along the shore of the East China Sea was investigated. The DNA extracted from 15 groundwater samples was subjected to PCR amplification of the dissimilatory sulfite reductase (dsr) gene. Full-length dsrAB amplicons (~1.9 kb) were then used to construct 4 clone libraries, while the dsrB amplicons (~350 bp) were used for denaturing gradient gel electrophoresis (DGGE) analysis. The clones in the 4 libraries covered all cultured SRB lineages, as well as a deeply branching clade not affiliated with any cultured SRB. In addition, nearly 80% of the 388 clones in the 4 libraries were similar to sequences of the Deltaproteobacteria, Desulfobacteriaceae, Desulfovibrionales, Syntrophaceae, and Desulfobulbaceae. Furthermore, a wide variety of marine SRB was detected, which indicated that seawater has infiltrated the aquifer. Indeed, the DGGE profiles revealed obvious variations in SRB diversity among the 15 samples, which clustered in accordance with the sulfate concentration of the samples ([SO42–]). Moreover, the sulfate concentrations and SRB diversity along the leachate plume did not show regular variation, which suggests the impact of both groundwater flow and seawater intrusion.

scholarly journals The Impact of Ecological Restoration on Biogeochemical Cycling and Mercury Mobilization in Anoxic Conditions on Former Mining Sites in French Guiana

2021 ◽  
Vol 9 (8) ◽  
pp. 1702
Author(s):  
Ewan Couic ◽  
Alicia Tribondeau ◽  
Vanessa Alphonse ◽  
Alexandre Livet ◽  
Michel Grimaldi ◽  
...  
Keyword(s):  
Ecological Restoration ◽  
French Guiana ◽  
Acacia Mangium ◽  
Anaerobic Conditions ◽  
Mining Sites ◽  
Iron Reducing Bacteria ◽  
Sulfate Reducing ◽  
Sulphide Production ◽  
Reducing Bacteria ◽  
The Impact

Successive years of gold mining in French Guiana has resulted in soil degradation and deforestation leading to the pollution and erosion of mining plots. Due to erosion and topography, gold panning sites are submitted to hydromorphy during rainfall and groundwater increases. This original study focused on characterizing the impact of hydromorphic anaerobic periods on bio-geochemical cycles. We sampled soil from five rehabilitated sites in French Guiana, including sites with herbaceous vegetation and sites restored with fabaceous plants, Clitoria racemosa (Cli) mon-oculture, Acacia mangium (Aca) monoculture, Clitoria racemosa and Acacia mangium (Mix) bi-culture. We conducted mesocosm experiments where soil samples were incubated in anaerobic conditions for 35 days. To evaluate the effect of anaerobic conditions on biogeochemical cycles, we measured the following parameters related to iron-reducing bacteria and sulfate-reducing bacteria metabolism throughout the experiment: CO2 release, carbon dissolution, sulphide production and sulphate mobilization. We also monitored the solubilization of iron oxyhydroxides, manganese oxides, aluminum oxides and mercury in the culture medium. Iron-reducing bacteria (IRB) and sulfate-reducing bacteria (SRB) are described as the major players in the dynamics of iron, sulfur and metal elements including mercury in tropical environments. The results revealed two trends in these rehabilitated sites. In the Aca and Mix sites, bacterial iron-reducing activity coupled with manganese solubilization was detected with no mercury solubilization. In herbaceous sites, a low anaerobic activity coupled with sulphide production and mercury solubilization were detected. These results are the first that report the presence and activity of iron- and sulfate-reductive communities at rehabilitated mining sites and their interactions with the dynamics of metallic elements and mercury. These results report, however, the positive impact of ecological restoration of mining sites in French Guiana by reducing IRB and SRB activities, the potential mobility of mercury and its risk of transfer and methylation.

Sign in / Sign up

Export Citation Format

Share Document