scholarly journals Butyrate Conversion by Sulfate-Reducing and Methanogenic Communities from Anoxic Sediments of Aarhus Bay, Denmark

2020 ◽  
Vol 8 (4) ◽  
pp. 606
Author(s):  
Derya Ozuolmez ◽  
Elisha K. Moore ◽  
Ellen C. Hopmans ◽  
Jaap S. Sinninghe Damsté ◽  
Alfons J. M. Stams ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Marine Sediments ◽  
Relative Abundance ◽  
Archaeal Community ◽  
Community Analysis ◽  
Sulfate Concentration ◽  
Vertical Separation ◽  
Sulfate Reducers ◽  
Sulfate Reducing ◽  
Initial Zone

The conventional perception that the zone of sulfate reduction and methanogenesis are separated in high- and low-sulfate-containing marine sediments has recently been changed by studies demonstrating their co-occurrence in sediments. The presence of methanogens was linked to the presence of substrates that are not used by sulfate reducers. In the current study, we hypothesized that both groups can co-exist, consuming common substrates (H2 and/or acetate) in sediments. We enriched butyrate-degrading communities in sediment slurries originating from the sulfate, sulfate–methane transition, and methane zone of Aarhus Bay, Denmark. Sulfate was added at different concentrations (0, 3, 20 mM), and the slurries were incubated at 10 °C and 25 °C. During butyrate conversion, sulfate reduction and methanogenesis occurred simultaneously. The syntrophic butyrate degrader Syntrophomonas was enriched both in sulfate-amended and in sulfate-free slurries, indicating the occurrence of syntrophic conversions at both conditions. Archaeal community analysis revealed a dominance of Methanomicrobiaceae. The acetoclastic Methanosaetaceae reached high relative abundance in the absence of sulfate, while presence of acetoclastic Methanosarcinaceae was independent of the sulfate concentration, temperature, and the initial zone of the sediment. This study shows that there is no vertical separation of sulfate reducers, syntrophs, and methanogens in the sediment and that they all participate in the conversion of butyrate.

scholarly journals Propionate Converting Anaerobic Microbial Communities Enriched from Distinct Biogeochemical Zones of Aarhus Bay, Denmark under Sulfidogenic and Methanogenic Conditions

2020 ◽  
Vol 8 (3) ◽  
pp. 394 ◽  
Author(s):  
Derya Ozuolmez ◽  
Alfons J. M. Stams ◽  
Caroline M. Plugge
Keyword(s):  
Bacterial Community ◽  
Sulfate Reduction ◽  
Marine Sediments ◽  
Archaeal Community ◽  
Community Analysis ◽  
Different Temperatures ◽  
Propionate Degradation ◽  
Whole Sediment ◽  
The Relationship ◽  
Sediment Bacterial Community

The relationship between predominant physiological types of prokaryotes in marine sediments and propionate degradation through sulfate reduction, fermentation, and methanogenesis was studied in marine sediments. Propionate conversion was assessed in slurries containing sediment from three different biogeochemical zones of Aarhus Bay, Denmark. Sediment slurries were amended with 0, 3, or 20 mM sulfate and incubated at 25 °C and 10 °C for 514–571 days. Methanogenesis in the sulfate zone and sulfate reduction in the methane zone slurries was observed. Both processes occurred simultaneously in enrichments originating from samples along the whole sediment. Bacterial community analysis revealed the dominance of Desulfobacteraceae and Desulfobulbaceae members in sulfate-amended slurries incubated at 25°C and 10°C. Cryptanaerobacter belonging to the Peptococcaceae family dominated sulfate-free methanogenic slurries at 25°C, whereas bacteria related to Desulfobacteraceae were dominant at 10°C. Archaeal community analysis revealed the prevalence of different genera belonging to Methanomicrobiales in slurries incubated at different temperatures and amended with different sulfate concentrations. Methanosarcinaceae were only detected in the absence of sulfate. In summary, Aarhus Bay sediment zones contain sulfate reducers, syntrophs, and methanogens interacting with each other in the conversion of propionate. Our results indicate that in Aarhus Bay sediments, Cryptanaerobacter degraded propionate in syntrophic association with methanogens.

scholarly journals Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations

2017 ◽  
Author(s):  
Zainab Abdulrahman Beiruti ◽  
Srijak Bhatnagar ◽  
Halina E. Tegetmeyer ◽  
Jeanine S. Geelhoed ◽  
Marc Strous ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Marine Sediments ◽  
Dynamic Environment ◽  
Community Response ◽  
Microbial Populations ◽  
Strictly Anaerobic ◽  
Sulfate Reducers ◽  
Sulfate Reducing ◽  
Trophic Networks ◽  
Nitrate Reducers

For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum , appeared to have coupled acetate oxidation to sulfate reduction. We described a novel representative of the widespread uncultured phylum Candidatus Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name Ca. “Sabulitectum silens” and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the metabolic network of fermentative and sulfate-reducing microbial populations, their niches, and adaptations to a dynamic environment.

scholarly journals Pseudodesulfovibrio cashew sp. Nov., a Novel Deep-Sea Sulfate-Reducing Bacterium, Linking Heavy Metal Resistance and Sulfur Cycle

2021 ◽  
Vol 9 (2) ◽  
pp. 429
Author(s):  
Rikuan Zheng ◽  
Shimei Wu ◽  
Chaomin Sun
Keyword(s):  
Heavy Metal ◽  
Sulfate Reduction ◽  
Marine Sediments ◽  
Deep Sea ◽  
Sulfur Cycle ◽  
Metal Sulfides ◽  
Phenotypic Traits ◽  
Dissimilatory Sulfate Reduction ◽  
Metabolic Potential ◽  
Sulfate Reducing

Sulfur cycling is primarily driven by sulfate reduction mediated by sulfate-reducing bacteria (SRB) in marine sediments. The dissimilatory sulfate reduction drives the production of enormous quantities of reduced sulfide and thereby the formation of highly insoluble metal sulfides in marine sediments. Here, a novel sulfate-reducing bacterium designated Pseudodesulfovibrio cashew SRB007 was isolated and purified from the deep-sea cold seep and proposed to represent a novel species in the genus of Pseudodesulfovibrio. A detailed description of the phenotypic traits, phylogenetic status and central metabolisms of strain SRB007 allowed the reconstruction of the metabolic potential and lifestyle of a novel member of deep-sea SRB. Notably, P. cashew SRB007 showed a strong ability to resist and remove different heavy metal ions including Co2+, Ni2+, Cd2+ and Hg2+. The dissimilatory sulfate reduction was demonstrated to contribute to the prominent removal capability of P. cashew SRB007 against different heavy metals via the formation of insoluble metal sulfides.

scholarly journals Diversity of Sulfur Isotope Fractionations by Sulfate-Reducing Prokaryotes

2001 ◽  
Vol 67 (2) ◽  
pp. 888-894 ◽  
Author(s):  
Jan Detmers ◽  
Volker Brüchert ◽  
Kirsten S. Habicht ◽  
Jan Kuever
Keyword(s):  
Sulfate Reduction ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Reduction Rate ◽  
Sulfate Reduction Rate ◽  
Dissimilatory Sulfate Reduction ◽  
Systematic Effect ◽  
Sulfate Reducers ◽  
Sulfate Reducing ◽  
Sulfur Isotope Fractionation

ABSTRACT Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.0 to 42.0‰. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation. Sulfate reducers that oxidized the carbon source completely to CO2 showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect isotope fractionation. Previous models that explained fractionation only in terms of sulfate reduction rates appear to be oversimplified. The species-specific physiology of each sulfate reducer thus needs to be taken into account to understand the regulation of sulfur isotope fractionation during dissimilatory sulfate reduction.

scholarly journals Sulfur Isotope Enrichment during Maintenance Metabolism in the Thermophilic Sulfate-Reducing Bacterium Desulfotomaculum putei

2009 ◽  
Vol 75 (17) ◽  
pp. 5621-5630 ◽  
Author(s):  
Mark M. Davidson ◽  
M. E. Bisher ◽  
Lisa M. Pratt ◽  
Jon Fong ◽  
Gordon Southam ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Batch Culture ◽  
Marine Sediments ◽  
Maintenance Phase ◽  
Laboratory Culture ◽  
Specific Rate ◽  
Culture Vessel ◽  
Isotope Enrichment ◽  
Sulfate Reducing ◽  
Sulfate Reduction Rates

ABSTRACT Values of Δ34S ( \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({=}{\delta}^{34}S_{HS}{-}{\delta}^{34}S_{SO_{4}}\) \end{document} , where δ34SHS and \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\delta}^{34}S_{SO_{4}}\) \end{document} indicate the differences in the isotopic compositions of the HS− and SO4 2− in the eluent, respectively) for many modern marine sediments are in the range of −55 to −75‰, much greater than the −2 to −46‰ ε34S (kinetic isotope enrichment) values commonly observed for microbial sulfate reduction in laboratory batch culture and chemostat experiments. It has been proposed that at extremely low sulfate reduction rates under hypersulfidic conditions with a nonlimited supply of sulfate, isotopic enrichment in laboratory culture experiments should increase to the levels recorded in nature. We examined the effect of extremely low sulfate reduction rates and electron donor limitation on S isotope fractionation by culturing a thermophilic, sulfate-reducing bacterium, Desulfotomaculum putei, in a biomass-recycling culture vessel, or “retentostat.” The cell-specific rate of sulfate reduction and the specific growth rate decreased progressively from the exponential phase to the maintenance phase, yielding average maintenance coefficients of 10−16 to 10−18 mol of SO4 cell−1 h−1 toward the end of the experiments. Overall S mass and isotopic balance were conserved during the experiment. The differences in the δ34S values of the sulfate and sulfide eluting from the retentostat were significantly larger, attaining a maximum Δ34S of −20.9‰, than the −9.7‰ observed during the batch culture experiment, but differences did not attain the values observed in marine sediments.

Competition for H2 between sulfate reducers, methanogens and homoacetogens in a gas-lift reactor

2002 ◽  
Vol 45 (10) ◽  
pp. 75-80 ◽  
Author(s):  
J. Weijma ◽  
F. Gubbels ◽  
L.W. Hulshoff Pol ◽  
A.J.M. Stams ◽  
P. Lens ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Sulfate Reduction ◽  
Growth Kinetic ◽  
Settling Velocity ◽  
Sulfate Reducing Bacteria ◽  
Anaerobic Sludge ◽  
Sulfate Reducers ◽  
Sulfate Reducing ◽  
Reducing Bacteria ◽  
Gas Lift

Reported values for growth kinetic parameters show an order in competitivity of heterotrophic sulfate reducing bacteria>methanogens>homoacetogens for the substrate hydrogen. This order suggests that methanogens can succesfully compete with consortia of heterotrophic SRB and homoacetogens when H2/CO2 is present as sole substrate. However, we found in experiments using gas-lift reactors inoculated with anaerobic sludge and fed with H2/CO2 and sulfate, that heterotrophic sulfate reduction rapidly and completely outcompeted methanogenesis, whereas a low amount of acetate was formed. Thus, in disagreement with the above competitivity order, hydrogen is more readily consumed by homoacetogenesis than by methanogenesis, indicating that the competition is not kinetically determined. The superior settling velocity of sulfidogenic-acetogenic sludge compared to that of methanogenic sludge suggests that the former sludge is better retained, which can explain the predominance of sulfate reduction/homoacetogenesis over methanogenesis.

scholarly journals Clustered Genes Related to Sulfate Respiration in Uncultured Prokaryotes Support the Theory of Their Concomitant Horizontal Transfer

2005 ◽  
Vol 187 (20) ◽  
pp. 7126-7137 ◽  
Author(s):  
Marc Mussmann ◽  
Michael Richter ◽  
Thierry Lombardot ◽  
Anke Meyerdierks ◽  
Jan Kuever ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Marine Sediments ◽  
Horizontal Transfer ◽  
Successful Implementation ◽  
Dissimilatory Sulfate Reduction ◽  
Prosthetic Group ◽  
Sulfate Reducing ◽  
Dissimilatory Sulfite Reductase ◽  
Sulfur Intermediates ◽  
Horizontal Transfers

ABSTRACT The dissimilatory reduction of sulfate is an ancient metabolic process central to today's biogeochemical cycling of sulfur and carbon in marine sediments. Until now its polyphyletic distribution was most parsimoniously explained by multiple horizontal transfers of single genes rather than by a not-yet-identified “metabolic island.” Here we provide evidence that the horizontal transfer of a gene cluster may indeed be responsible for the patchy distribution of sulfate-reducing prokaryotes (SRP) in the phylogenetic tree. We isolated three DNA fragments (32 to 41 kb) from uncultured, closely related SRP from DNA directly extracted from two distinct marine sediments. Fosmid ws39f7, and partially also fosmids ws7f8 and hr42c9, harbored a core set of essential genes for the dissimilatory reduction of sulfate, including enzymes for the reduction of sulfur intermediates and synthesis of the prosthetic group of the dissimilatory sulfite reductase. Genome comparisons suggest that encoded membrane proteins universally present among SRP are critical for electron transfer to cytoplasmic enzymes. In addition, novel, conserved hypothetical proteins that are likely involved in dissimilatory sulfate reduction were identified. Based on comparative genomics and previously published experimental evidence, a more comprehensive model of dissimilatory sulfate reduction is presented. The observed clustering of genes involved in dissimilatory sulfate reduction has not been previously found. These findings strongly support the hypothesis that genes responsible for dissimilatory sulfate reduction were concomitantly transferred in a single event among prokaryotes. The acquisition of an optimized gene set would enormously facilitate a successful implementation of a novel pathway.

Competition between methanogenesis and sulfidogenesis in anaerobic wastewater treatment

1998 ◽  
Vol 38 (8-9) ◽  
pp. 317-324 ◽  
Author(s):  
Gong-Ming Zhou ◽  
Herbert H. P. Fang
Keyword(s):  
Wastewater Treatment ◽  
Sulfate Reduction ◽  
Methane Production ◽  
Reduction Rate ◽  
Uasb Reactor ◽  
Sulfate Reduction Rate ◽  
Sulfate Concentration ◽  
Anaerobic Wastewater Treatment ◽  
Sulfate Reducing ◽  
Sulfate Removal

This study was conducted to investigate the methanogenic and sulfidogenic activities of biomass in a UASB reactor treating wastewater containing benzoate (680 mg l−1) and sulfate (increased from 1080 to 2680 mg l−1) at 37°C and 12 hours of hydraulic retention. Results showed that after 120 days of acclimation, sludge consistently removed 99.5% of benzoate regardless of increased sulfate concentrations. Sulfidogenesis gradually out-competed methanogenesis during the acclimation phase, as indicated by the increase of sulfate-reducing efficiency (up to 99%) accompanied by the decrease of methane production. Overall sulfate removal efficiency was limited after the reactor had reached its maximum sulfate reduction rate of 2.1 g S (l d−1). Further increasing sulfate concentration from 1080 mg l−1 to 2680 mg l−1 lowered the sulfate-reducing efficiency from 85% to 39%. Flow of available electrons toward sulfidogenesis increased with the decrease of benzoate concentration, and was only slightly affected by the sulfate concentration or the benzoate/SO42−-S ratio.

scholarly journals Sulfate-Reducing Bacteria Methylate Mercury at Variable Rates in Pure Culture and in Marine Sediments

2000 ◽  
Vol 66 (6) ◽  
pp. 2430-2437 ◽  
Author(s):  
Jeffrey K. King ◽  
Joel E. Kostka ◽  
Marc E. Frischer ◽  
F. Michael Saunders
Keyword(s):  
Sulfate Reduction ◽  
Marine Sediments ◽  
Marine Sediment ◽  
Pure Culture ◽  
Sulfate Reducing Bacteria ◽  
Mercury Methylation ◽  
Sulfate Reducing ◽  
The Family ◽  
Pure Cultures ◽  
Reducing Bacteria

ABSTRACT Differences in methylmercury (CH3Hg) production normalized to the sulfate reduction rate (SRR) in various species of sulfate-reducing bacteria (SRB) were quantified in pure cultures and in marine sediment slurries in order to determine if SRB strains which differ phylogenetically methylate mercury (Hg) at similar rates. Cultures representing five genera of the SRB (Desulfovibrio desulfuricans, Desulfobulbus propionicus,Desulfococcus multivorans, Desulfobacter sp. strain BG-8, and Desulfobacterium sp. strain BG-33) were grown in a strictly anoxic, minimal medium that received a dose of inorganic Hg 120 h after inoculation. The mercury methylation rates (MMR) normalized per cell were up to 3 orders of magnitude higher in pure cultures of members of SRB groups capable of acetate utilization (e.g., the family Desulfobacteriaceae) than in pure cultures of members of groups that are not able to use acetate (e.g., the family Desulfovibrionaceae). Little or no Hg methylation was observed in cultures of Desulfobacterium orDesulfovibrio strains in the absence of sulfate, indicating that Hg methylation was coupled to respiration in these strains. Mercury methylation, sulfate reduction, and the identities of sulfate-reducing bacteria in marine sediment slurries were also studied. Sulfate-reducing consortia were identified by using group-specific oligonucleotide probes that targeted the 16S rRNA molecule. Acetate-amended slurries, which were dominated by members of the Desulfobacterium and Desulfobacter groups, exhibited a pronounced ability to methylate Hg when the MMR were normalized to the SRR, while lactate-amended and control slurries had normalized MMR that were not statistically different. Collectively, the results of pure-culture and amended-sediment experiments suggest that members of the family Desulfobacteriaceae have a greater potential to methylate Hg than members of the familyDesulfovibrionaceae have when the MMR are normalized to the SRR. Hg methylation potential may be related to genetic composition and/or carbon metabolism in the SRB. Furthermore, we found that in marine sediments that are rich in organic matter and dissolved sulfide rapid CH3Hg accumulation is coupled to rapid sulfate reduction. The observations described above have broad implications for understanding the control of CH3Hg formation and for developing remediation strategies for Hg-contaminated sediments.

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