scholarly journals Energy metabolism and uranium (VI) reduction by Desulfovibrio

2005 ◽  
Author(s):  
◽  
Rayford B. Payne
Keyword(s):  
Energy Source ◽  
Energy Metabolism ◽  
Organic Compounds ◽  
Hydrogen Gas ◽  
Contaminated Groundwater ◽  
Human Beings ◽  
Cytochrome C3 ◽  
Uranium Reduction ◽  
Sulfate Reducing ◽  
Reducing Bacteria

Sulfate reducing bacteria (SRB) of the genus Desulfovibrio can breathe uranium in a manner similar to the way in which we (human beings) breathe oxygen. In respiration, we transfer electrons from food to oxygen, producing water, SRB transfer electrons of uranium (VI) to uranium (IV). (This transfer of electrons is also called reduction.) The reduction of U(VI) to U(IV) alters the solubility state of the uranium from a soluble to an insoluble, and therefore less biologically available, form. Because SRB are commonly found in uranium contaminated groundwater and soil, it is theoretically possible that we could use them to bioremediate uranium contaminated environments. However, before we attempt to use SRB to bioremediate uranium contaminated environments, we must first understand the SRB genes and enzymes involved in the process of uranium reduction. We have determined that the enzyme cytochrome c3 can act as a U(VI) reductase by Desulfovibrio when hydrogen gas is the energy source; however, alternate pathways utilizing organic compounds for U(VI) reduction exist. In addition, we have observed that Desulfovibrio that have been previously exposed to uranium (such as those bacteria that would be found in a uranium contaminated environment) are impaired in utilizing some organic compounds, but not hydrogen gas, as an energy source for uranium (VI) reduction. This suggests that in order for us to use SRB to treat uranium contaminated environments, it would be more efficient to add hydrogen gas, not organic compounds, as an energy source for the SRB.

scholarly journals Proteogenomic Insights into the Physiology of Marine, Sulfate-Reducing, Filamentous Desulfonema limicola and Desulfonema magnum

2021 ◽  
Vol 31 (1) ◽  
pp. 36-56
Author(s):  
Vanessa Schnaars ◽  
Lars Wöhlbrand ◽  
Sabine Scheve ◽  
Christina Hinrichs ◽  
Richard Reinhardt ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Gene Clusters ◽  
Transport Systems ◽  
Natural Habitats ◽  
Sulfate Reducing ◽  
Type Iv ◽  
Aromatic Compound Degradation ◽  
High Degree ◽  
Reducing Bacteria ◽  
Gliding Movement

The genus Desulfonema belongs to the deltaproteobacterial family Desulfobacteraceae and comprises marine, sulfate-reducing bacteria that form filaments and move by gliding. This study reports on the complete, manually annotated genomes of Dn. limicola 5ac10T (6.91 Mbp; 6,207 CDS) and Dn. magnum 4be13T (8.03 Mbp; 9,970 CDS), integrated with substrate-specific proteome profiles (8 vs. 11). The richness in mobile genetic elements is shared with other Desulfobacteraceae members, corroborating horizontal gene transfer as major driver in shaping the genomes of this family. The catabolic networks of Dn. limicola and Dn. magnum have the following general characteristics: 98 versus 145 genes assigned (having genomic shares of 1.7 vs. 2.2%), 92.5 versus 89.7% proteomic coverage, and scattered gene clusters for substrate degradation and energy metabolism. The Dn. magnum typifying capacity for aromatic compound degradation (e.g., p-cresol, 3-phenylpropionate) requires 48 genes organized in operon-like structures (87.7% proteomic coverage; no homologs in Dn. limicola). The protein complements for aliphatic compound degradation, central pathways, and energy metabolism are highly similar between both genomes and were identified to a large extent (69–96%). The differential protein profiles revealed a high degree of substrate-specificity for peripheral reaction sequences (forming central intermediates), agreeing with the high number of sensory/regulatory proteins predicted for both strains. By contrast, central pathways and modules of the energy metabolism were constitutively formed under the tested substrate conditions. In accord with their natural habitats that are subject to fluctuating changes of physicochemical parameters, both Desulfonema strains are well equipped to cope with various stress conditions. Next to superoxide dismutase and catalase also desulfoferredoxin and rubredoxin oxidoreductase are formed to counter exposure to molecular oxygen. A variety of proteases and chaperones were detected that function in maintaining cellular homeostasis upon heat or cold shock. Furthermore, glycine betaine/proline betaine transport systems can respond to hyperosmotic stress. Gliding movement probably relies on twitching motility via type-IV pili or adventurous motility. Taken together, this proteogenomic study demonstrates the adaptability of Dn. limicola and Dn. magnum to its dynamic habitats by means of flexible catabolism and extensive stress response capacities.

Field-scale bioremediation of arsenic-contaminated groundwater using sulfate-reducing bacteria and biogenic pyrite

2018 ◽  
Vol 23 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Ming-Kuo Lee ◽  
James A. Saunders ◽  
Theodore Wilson ◽  
Eric Levitt ◽  
Shahrzad Saffari Ghandehari ◽  
...  
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Contaminated Groundwater ◽  
Field Scale ◽  
Sulfate Reducing ◽  
Reducing Bacteria

Identification of the genes for hydrogenase and cytochrome c3 in Desulfovibrio

1987 ◽  
Vol 33 (11) ◽  
pp. 1006-1010 ◽  
Author(s):  
Gerrit Voordouw ◽  
Helen M. Kent ◽  
John R. Postgate
Keyword(s):  
Cytochrome C ◽  
Sequence Divergence ◽  
Desulfovibrio Vulgaris ◽  
Gene Probe ◽  
Cytochrome C3 ◽  
Sulfate Reducing ◽  
Genes Encoding ◽  
Reducing Bacteria ◽  
Cryptic Plasmids ◽  
Amino Acid Sequence Divergence

Cloned genes encoding cytochrome c3 and hydrogenase from Desulfovibrio vulgaris Hildenborough have been used to probe the genomes of 15 other desulfovibrios. The D. vulgaris strains Wandle and Brockhurst Hill cannot be distinguished from the Hildenborough strain by Southern hybridization using either probe, indicating similar genomes. Desulfovibrio vulgaris Groningen is completely different and lacks homologous cytochrome c3 and hydrogenase genes. The genomes of D. vulgaris ssp. oxamicus Monticello and D. desulfuricans strains El Agheila Z, Berre sol, and Canet 41 contain genes encoding a homologous but not identical periplasmic hydrogenase and cytochrome c3. Weak hybridization was observed with the cytochrome c3 gene probe for genomes of seven other sulfate-reducing bacteria, which reflects the known amino acid sequence divergence of cytochrome c3 in Desulfovibrio. The hydrogenase gene probe shows weak hybridization to the DNA from two strains of D. salexigens only, while the gene may be absent from D. vulgaris Groningen, two strains of D. africanus, D. thermophilus, D. gigas, and D. desulfuricans strains Norway and Teddington R. In desulfovibrios carrying cryptic plasmids the cytochrome c3 and hydrogenase genes are apparently chromosomal.

A Review on Volatile Organic Compounds (VOCs) as Environmental Pollutants: Fate and Distribution

2018 ◽  
Vol 4 (02) ◽  
pp. 14-26 ◽  
Author(s):  
Puneeta Pandey ◽  
Radheshyam Yadav
Keyword(s):  
Health Effects ◽  
Organic Compounds ◽  
Health Risks ◽  
Environmental Pollutants ◽  
Contaminated Groundwater ◽  
Human Beings ◽  
Adverse Health Effects ◽  
Household Products ◽  
Volatile Organic ◽  
Concentration Levels

VOCs include a variety of organic chemicals emitted as gases from certain solids and liquids. The nature and extent of these health effects depend on the concentration levels of these VOCs and the duration of their exposure and pose adverse health effects to humans. Although VOCs are found in a variety of industrial, commercial and household products; it is their concentration in wells and groundwater that has gained attention in recent years. When VOCs are spilled or improperly disposed of, a portion of it after evaporation are soaked on the ground, which eventually reaches wells and groundwater. Drinking of inadequately treated VOCs contaminated groundwater is potentially harmful to human beings. Trichloroethylene and vinyl chloride are most toxic and carcinogenic among all VOCs. The present paper reviews the sources, health risks, transport and fate of these VOCs in groundwater. Besides, analytical methods for the detection of VOCs in groundwater and techniques for mitigation of VOCs from groundwater have also been discussed.

scholarly journals Thermophilic sulfate-reducing bacteria Moorela thermoacetica Nadia-3, isolated from “Nadiia” pit spoil heap of Chervonohrad mining region

2021 ◽  
Vol 15 (2) ◽  
pp. 35-46
Author(s):  
O. M. Сhayka ◽  
◽  
T. B. Peretyatko ◽  
A. A. Halushka ◽  
Keyword(s):  
Hydrogen Sulfide ◽  
Metal Ions ◽  
Organic Compounds ◽  
Elemental Sulfur ◽  
Sulfate Reducing Bacteria ◽  
Sulfate Reducing ◽  
Spoil Heap ◽  
Mining Region ◽  
Living Organisms ◽  
Reducing Bacteria

Introduction. Thermophilic sulfate-reducing bacteria attract attention of scientists as the potential agents of purification of wastewater polluted by sulfur and its compounds, heavy metal ions and organic compounds. These bacteria oxidize different organic substrates using metals with variable valency as electron acceptors and transform them into non-toxic or less toxic forms for living organisms. However, wastewater contains high concentrations of different toxic xenobiotics, particularly, metal ions that have negative influence on living organisms. For this reason, it is important to use resistant strains of microorganisms for the purification of wastewater. The aim of this work was to identify the thermophilic sulfur-reducing bacteria, isolated from “Nadiia” pit spoil heap of Chervonohrad mining region, and to study their properties. Materials and Methods. Thermophilic sulfur-reducing bacteria were isolated from the samples of rock of “Nadiia” pit heap at 50 cm depth. Bacteria were cultivated in TF medium under the anaerobic conditions in anaerostates. Cell biomass was measured turbidimetrically using the photoelectric colorimeter KFK-3 (λ = 340 nm, 3 mm cuvette). Hydrogen sulfide content was measured photoelectrocolorymetrically by the production of methylene blue. Organic acids content was measured by high performance liquid chromatography. Cr(VI), Fe(III), Мn(IV) and NO3– content was measured turbidimetrically. Results. Thermophilic sulfur-reducing bacteria were isolated from the rock of “Nadiia” pit heap of Chervonohrad mining region. They were identified as Moorela thermoacetica based on the morpho-physiological and biochemical properties and on the results of phylogenetic analysis. M. thermoacetica Nadia-3 grow in the synthetic TF medium, have the shape of elongated rods, are gram-positive, endospore-forming. They form light brown colonies. Optimal growth was observed at 50–55 °C, pH 6.5–7. The bacteria utilize glucose, starch, fructose, maltose, lactose, sodium lactate, arabinose, cellulose, maltose, glycerol, fumarate, and ethanol as carbon sources. The highest sulfidogenic activity of M. thermoacetica Nadia-3 was found in media with glycerol, lactose, and glucose. M. thermoacetica Nadia-3 reduce SO42-, S2O32-, Fe(III), NO3–, Cr(VI) compounds besides elemental sulfur. They accumulate biomass at K2Cr2O7 concentrations of 0.1–1 mM. Sulfur reduction is not the main way of energy accumulation. Conclusions. Thermophilic chromium-resistant sulfur-reducing bacteria M. thermoacetica Nadia-3, that produce hydrogen sulfide during the oxidation of different organic compounds, were isolated from the rock of “Nadiia” pit heap. They reduce Fe(III), Cr(VI), NO3–, SO42-, S2O32-, besides elemental sulfur.

scholarly journals Novel Asgard archaea phylum Hermodarchaeota degrade alkanes and aromatics via alkyl/benzyl-succinate synthase and benzoyl-CoA pathway

2020 ◽  
Author(s):  
Jia-Wei Zhang ◽  
Hong-Po Dong ◽  
Li-Jun Hou ◽  
Yang Liu ◽  
Ya-Fei Ou ◽  
...  
Keyword(s):  
16S Rrna ◽  
Carbon Cycling ◽  
Organic Compounds ◽  
Aromatic Compounds ◽  
Coenzyme A ◽  
Mangrove Sediments ◽  
Freshwater Sediments ◽  
Sulfate Reducing ◽  
Genes Encoding ◽  
Reducing Bacteria

AbstractAsgard superphylum is composed of a group of uncultivated archaea that are deemed the closest relatives of eukaryotes. These archaea are widely distributed in anaerobic environments and suggested to be important players in carbon cycling of sediments. Alkanes and aromatics are refractory organic compounds and abundant in sediments. However, little is known about degradation of these compounds by Asgard archaea to date. Here, we describe a previously unrecognized archaeal phylum, Hermodarchaeota, affiliated with the Asgard superphylum. The genomes of these archaea were recovered in metagenomes from mangrove sediments, and were found to encode alkyl/benzyl-succinate synthases and their activating enzymes that are similar to those found in alkanes-degrading sulfate-reducing bacteria. Hermodarchaeota also encode enzymes for alkyl-coenzyme A and benzoyl-coenzyme A oxidation, and the Wood–Ljungdahl pathway, as well as nitrate reductases. Furthermore, transcripts for these enzymes have been frequently detected in metatranscriptomes from mangrove sediments. This indicates that members of this phylum are able to anaerobically oxidize alkanes and aromatic compounds, coupling the reduction of nitrate. Genes encoding 16S rRNA and alkyl/benzyl-succinate synthases analogous to those in Hermodarchaeota were identified in a range of marine and freshwater sediments. These findings suggest that Asgard archaea capable of degrading alkanes and aromatics via formation of alkyl/benzyl-substituted succinates are ubiquitous in sediments.

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