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![Phylogenetic analysis of representatives of the genus Desulfosporosinus based on concatenated amino acid sequences of 32 ribosomal proteins. The evolutionary history was inferred by using the Maximum Likelihood method based on the JTT matrix-based model [7]. The tree with the highest log likelihood (−27,426.3925) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The analysis involved 12 amino acid sequences. All positions containing gaps and missing data were eliminated. There were a total of 4259 positions in the final dataset. Evolutionary analyses were conducted in MEGA7 [12].](publication/311972865/figure/fig1/AS:451419112251392@1484638111336/Phylogenetic-analysis-of-representatives-of-the-genus-Desulfosporosinus-based-on.png)
Phylogenetic analysis of representatives of the genus Desulfosporosinus based on concatenated amino acid sequences of 32 ribosomal proteins. The evolutionary history was inferred by using the Maximum Likelihood method based on the JTT matrix-based model [7]. The tree with the highest log likelihood (−27,426.3925) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The analysis involved 12 amino acid sequences. All positions containing gaps and missing data were eliminated. There were a total of 4259 positions in the final dataset. Evolutionary analyses were conducted in MEGA7 [12].
Source publication
Here, we report on the draft genome of a copper-resistant and acidophilic Desulfosporosinus sp. BG, isolated from the tailings of a molybdenum-tungsten mine in Transbaikal area. The draft genome has a size of 4.52Mb and encodes transporters of heavy metals. The phylogenetic analysis based on concatenated ribosomal proteins revealed that strain BG c...
Citations
... An acidophilic Desulfosporosinus sp. BG from a tungsten mine waste in Bom-Gorkhon in Transbaikalia tolerated the presence of copper up to a concentration of 78 mM [5,14]. Various metal transporters and sequestration by polyphosphates were revealed as possible mechanisms to survive high copper concentrations in Desulfosporosinus sp. ...
A novel, spore-forming, acidophilic and metal-resistant sulfate-reducing bacterium, strain OL T , was isolated from a microbial mat in a tailing dam at a gold ore mining site. Cells were slightly curved immotile rods, 0.5 µm in diameter and 2.0–3.0 µm long. Cells were stained Gram-negative, despite the Gram-positive cell structure revealed by electron microscopy of ultrathin layers. OL T grew at pH 4.0–7.0 with an optimum at 5.5. OL T utilised H 2 , lactate, pyruvate, malate, formate, propionate, ethanol, glycerol, glucose, fructose, sucrose, peptone and tryptone as electron donors for sulfate reduction. Sulfate, sulfite, thiosulfate, nitrate and fumarate were used as electron acceptors in the presence of lactate. Elemental sulfur, iron (III), and arsenate did not serve as electron acceptors. The major cellular fatty acids were C 16:1 ω7 c (39.0 %) and C 16 : 0 (12.1 %). The draft genome of OL T was 5.29 Mb in size and contained 4909 protein-coding genes. The 16S rRNA gene sequence placed OL T within the phylum Firmicutes , class Clostridia , family Peptococcaceae , genus Desulfosporosinus. Desulfosporosinus nitroreducens 59.4B T was the closest relative with 97.6 % sequence similarity. On the basis of phenotypic and phylogenetic characteristics, strain OL T represents a novel species within the genus Desulfosporosinus , for which we propose the name Desulfosporosinus metallidurans sp. nov. with the type strain OL T (=DSM 104464 T =VKM В−3021 T ).
... Numerous natural and mining-impacted acidic sites of Eastern Transbaikalia, Russia, are located in the area of headwaters of the river Amur, more than 1,000 km eastwards of the lake Baikal, and represent a generous source of distinctive extreme environments. This area remains microbiologically under sampled with only a small number of recent studies available that were mostly dedicated to the diversity of sulfate-reducing bacteria (Karnachuk et al., , 2016Kadnikov et al., 2016 and others). The present work is focused on the elucidation of diversity of microbial inhabitants in three different types of acidic settings in this area. ...
... Desulfosporosinus (the family Peptococcaceae) representatives are known to populate acidic settings, those include few acidophilic sulfate-reducers isolated so far in pure cultures: D. acidiphilus from a mining site at Chessy-Les-Mines, France (Alazard et al., 2010), D. acididurans from White River sediment in Montserrat (Sánchez-Andrea et al., 2015) and Desulfosporosinus sp. strain BG from oxidized mining wastes in Northern Transbaikalia (Karnachuk et al., , 2016. The latter was reported to tolerate high concentrations of copper and produce crystalline copper sulfides . ...
Acid mine drainage (AMD) systems are globally widespread and are an important source of metal pollution in riverine and coastal systems. Microbial AMD communities have been extensively studied for their ability to thrive under extremely acidic conditions and for their immense contribution to the dissolution of metal ores. However, little is known on microbial inhabitants of AMD systems subjected to extremely contrasting continental seasonal temperature patterns as opposed to maritime climate zones, experiencing much weaker annual temperature variations. Here, we investigated three types of AMD sites in Eastern Transbaikalia (Russia). In this region, all surface water bodies undergo a deep and long (up to 6 months) freezing, with seasonal temperatures varying between −33 and +24°C, which starkly contrasts the common well-studied AMD environments. We sampled acidic pit lake (Sherlovaya Gora site) located in the area of a polymetallic deposit, acidic drainage water from Bugdaya gold-molybdenum-tungsten deposit and Ulan-Bulak natural acidic spring. These systems showed the abundance of bacteria-derived reads mostly affiliated with Actinobacteria, Acidobacteria, Alpha- and Gammaproteobacteria, chloroplasts, Chloroflexi, Bacteroidetes, and Firmicutes. Furthermore, candidate taxa “Ca. Saccharibacteria” (previously known as TM7), “Ca. Parcubacteria” (OD1) and WPS-2 were represented in substantial quantities (10–20%). Heterotrophy and iron redox cycling can be considered as central processes of carbon and energy flow for majority of detected bacterial taxa. Archaea were detected in low numbers, with Terrestrial Miscellaneous Euryarchaeal Group (TMEG), to be most abundant (3%) in acidic spring Ulan-Bulak. Composition of these communities was found to be typical in comparison to other AMD sites; however, certain groups (as Ignavibacteriae) could be specifically associated with this area. This study provides insight into the microbial diversity patterns in acidic ecosystems formed in areas of polymetallic deposits in extreme continental climate zone with contrasting temperature parameters.
... Hitherto, two acidophilic SRB, Desulfosporosinus acidiphilus and Desulfosporosinus acididurans, have been characterised by Alazard et al. (2010) and Sánchez-Andrea et al. (2015). Several undescribed members of this genus have been reported, which grow in acidic media (Abicht et al. 2011;Jameson et al. 2010;Karnachuk et al. 2009Karnachuk et al. , 2015aKarnachuk et al. , 2017Küsel et al. 2001;Senko et al. 2009). Another member of the Firmicutes phylum, the thermophilic SRB Thermodesulfobium narugense isolated from a hot spring, has a slightly acidic pH optimum of 5.5-6.0 for growth (Mori et al. 2003). ...
Almost all the known isolates of acidophilic or acid-tolerant sulphate-reducing bacteria (SRB) belong to the spore-forming genus Desulfosporosinus in the Firmicutes. The objective of this study was to isolate acidophilic/acid-tolerant members of the genus Desulfovibrio belonging to deltaproteobacterial SRB. The sample material originated from microbial mat biomass submerged in mine water and was enriched for sulphate reducers by cultivation in anaerobic medium with lactate as an electron donor. A stirred tank bioreactor with the same medium composition was inoculated with the sulphidogenic enrichment. The bioreactor was operated with a temporal pH gradient, changing daily, from an initial pH of 7.3 to a final pH of 3.7. Among the bacteria in the bioreactor culture, Desulfovibrio was the only SRB group retrieved from the bioreactor consortium as observed by 16S rRNA-targeted denaturing gradient gel electrophoresis. Moderately acidophilic/acid-tolerant isolates belonged to Desulfovibrio aerotolerans-Desulfovibrio carbinophilus-Desulfovibrio magneticus and Desulfovibrio idahonensis-Desulfovibrio mexicanus clades within the genus Desulfovibrio. A moderately acidophilic strain, Desulfovibrio sp. VK (pH optimum 5.7) and acid-tolerant Desulfovibrio sp. ED (pH optimum 6.6) dominated in the bioreactor consortium at different time points and were isolated in pure culture.
The biological route of nitrate reduction has important implications for the bioavailability of nitrogen within ecosystems. Nitrate reduction via nitrite, either to ammonium (ammonification) or to nitrous oxide or dinitrogen (denitrification), determines whether nitrogen is retained within the system or lost as a gas. The acidophilic sulfate-reducing bacterium (aSRB) Acididesulfobacillus acetoxydans can perform dissimilatory nitrate reduction to ammonium (DNRA). While encoding a Nar-type nitrate reductase, A. acetoxydans lacks recognized nitrite reductase genes. In this study, A. acetoxydans was cultivated under conditions conducive to DNRA. During cultivations, we monitored the production of potential nitrogen intermediates (nitrate, nitrite, nitric oxide, hydroxylamine, and ammonium). Resting cell experiments were performed with nitrate, nitrite, and hydroxylamine to confirm their reduction to ammonium, and formed intermediates were tracked. To identify the enzymes involved in DNRA, comparative transcriptomics and proteomics were performed with A. acetoxydans growing under nitrate- and sulfate-reducing conditions. Nitrite is likely reduced to ammonia by the previously undescribed nitrite reductase activity of the NADH-linked sulfite reductase AsrABC, or by a putatively ferredoxin-dependent homolog of the nitrite reductase NirA (DEACI_1836), or both. We identified enzymes and intermediates not previously associated with DNRA and nitrosative stress in aSRB. This increases our knowledge about the metabolism of this type of bacteria and helps the interpretation of (meta)genome data from various ecosystems on their DNRA potential and the nitrogen cycle.
IMPORTANCE
Nitrogen is crucial to any ecosystem, and its bioavailability depends on microbial nitrogen-transforming reactions. Over the recent years, various new nitrogen-transforming reactions and pathways have been identified, expanding our view on the nitrogen cycle and metabolic versatility. In this study, we elucidate a novel mechanism employed by Acididesulfobacillus acetoxydans, an acidophilic sulfate-reducing bacterium, to reduce nitrate to ammonium. This finding underscores the diverse physiological nature of dissimilatory reduction to ammonium (DNRA). A. acetoxydans was isolated from acid mine drainage, an extremely acidic environment where nitrogen metabolism is poorly studied. Our findings will contribute to understanding DNRA potential and variations in extremely acidic environments.
Redox transformations of sulfur, involving dissimilatory and assimilatory oxidation and reduction reactions, occurs in water bodies and terrestrial environments worldwide, leading to dynamic cycling of this element throughout the biosphere. In cases where zero-valent (elemental) sulfur, sulfate and other oxidized forms are used as electron acceptor in (primarily) anaerobic microbial metabolisms, the end product is hydrogen sulfide (HS- or H2S, dependent on pH). While neutrophilic and alkalophilic sulfidogenic prokaryotes have been known for many decades, acid-tolerant and acidophilic strains and species have been isolated and characterized only in the past twenty or so years, even though evidence for sulfide generation on these environments was previously well documented. This review outlines the background and current status of the biodiversity and metabolisms of sulfate- and sulfur-reducing prokaryotes that are metabolically active in low pH environments, and describes the developing technologies in which they are being used to remediate acidic waste waters (which are often metal-contaminated) and to recover metal resources.
Recent reports on antimicrobial effects of metallic Cu prompted this study of anaerobic microbial communities on copper surfaces. Widely circulating copper-containing coinage was used as a potential source for microorganisms that had had human contact and were tolerant to copper. This study reports on the isolation, characterization, and genome of an anaerobic sulfidogenic Tissierella sp. P1from copper-containing brass coinage. Dissimilatory (bi)sulfite reductase dsrAB present in strain P1 genome and the visible absorbance around 630 nm in the cells suggested the presence of a desulfoviridin-type protein. However, the sulfate reduction rate measurements with 35SO4 2� did not confirm the dissimilatory sulfate reduction by the strain. The P1 genome lacks APS reductase, sulfate adenylyltransferase, DsrC, and DsrMK necessary for dissimilatory sulfate reduction. The isolate produced up to 0.79mMH2S during growth, possibly due to cysteine synthase (CysK) and/or cysteine desulfhydrase (CdsH) activities, encoded in the genome. The strain can tolerate up to 2.4mM Cu2þ(150 mg/l) in liquid medium, shows affinity to metallic copper, and can survive on copper-containing coins up to three days under ambient air and dry conditions. The genome sequence of strain P1 contained cutC, encoding a copper resistance protein, which distinguishes it from all other Tissierella strains with published genomes.
Sulfate-reducing bacteria (SRB) are a group of diverse anaerobic microorganisms omnipresent in natural habitats and engineered environments that use sulfur compounds as the electron acceptor for energy metabolism. Dissimilatory sulfate reduction (DSR)-based techniques mediated by SRB have been utilized in many sulfate-containing wastewater treatment systems worldwide, particularly for acid mine drainage, groundwater, sewage and industrial wastewater remediation. However, DSR processes are often operated suboptimally and disturbances are common in practical application. To improve the efficiency and robustness of SRB-based processes, it is necessary to study SRB metabolism and operational conditions. In this review, the mechanisms of DSR processes are reviewed and discussed focusing on intracellular and extracellular electron transfer with different electron donors (hydrogen, organics, methane and electrodes). Based on the understanding of the metabolism of SRB, responses of SRB to environmental stress (pH-, temperature-, and salinity-related stress) are summarized at the species and community levels. Application in these stressed conditions is discussed and future research is proposed. The feasibility of recovering energy and resources such as biohydrogen, hydrocarbons, polyhydroxyalkanoates, magnetite and metal sulfides through the use of SRB were investigated but some long-standing questions remain unanswered. Linking the existing scientific understanding and observations to practical application is the challenge as always for promotion of SRB-based techniques.
