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Johnston KKY, van Lankveld M, de Rink R, Roman P, Klok JBM, Mol AR, Keesman KJ, Buisman CJN. Polysulfide Concentration and Chain Length in the Biological Desulfurization Process: Effect of Biomass Concentration and the Sulfide Loading Rate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13530-13540. [PMID: 37639370 PMCID: PMC10501124 DOI: 10.1021/acs.est.3c03017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023]
Abstract
Removal of hydrogen sulfide (H2S) can be achieved using the sustainable biological desulfurization process, where H2S is converted to elemental sulfur using sulfide-oxidizing bacteria (SOB). A dual-bioreactor process was recently developed where an anaerobic (sulfidic) bioreactor was used between the absorber column and micro-oxic bioreactor. In the absorber column and sulfidic bioreactor, polysulfides (Sx2-) are formed due to the chemical equilibrium between H2S and sulfur (S8). Sx2- is thought to be the intermediate for SOB to produce sulfur via H2S oxidation. In this study, we quantify Sx2-, determine their chain-length distribution under high H2S loading rates, and elucidate the relationship between biomass and the observed biological removal of sulfides under anaerobic conditions. A linear relationship was observed between Sx2- concentration and H2S loading rates at a constant biomass concentration. Increasing biomass concentrations resulted in a lower measured Sx2- concentration at similar H2S loading rates in the sulfidic bioreactor. Sx2- of chain length 6 (S62-) showed a substantial decrease at higher biomass concentrations. Identifying Sx2- concentrations and their chain lengths as a function of biomass concentration and the sulfide loading rate is key in understanding and controlling sulfide uptake by the SOB. This knowledge will contribute to a better understanding of how to reach and maintain a high selectivity for S8 formation in the dual-reactor biological desulfurization process.
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Affiliation(s)
- Kestral
A. K. Y. Johnston
- Environmental
Technology, Wageningen University &
Research, P.O. Box 17, 6700
AA Wageningen, The
Netherlands
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 AD Leeuwarden, The Netherlands
| | - Mark van Lankveld
- Environmental
Technology, Wageningen University &
Research, P.O. Box 17, 6700
AA Wageningen, The
Netherlands
- Paqell
B.V., Reactorweg 301, 3542 AD Utrecht, The Netherlands
| | - Rieks de Rink
- Environmental
Technology, Wageningen University &
Research, P.O. Box 17, 6700
AA Wageningen, The
Netherlands
- Paqell
B.V., Reactorweg 301, 3542 AD Utrecht, The Netherlands
| | - Pawel Roman
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 AD Leeuwarden, The Netherlands
| | - Johannes B. M. Klok
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 AD Leeuwarden, The Netherlands
| | - Annemerel R. Mol
- Environmental
Technology, Wageningen University &
Research, P.O. Box 17, 6700
AA Wageningen, The
Netherlands
| | - Karel J. Keesman
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 AD Leeuwarden, The Netherlands
- Mathematical
and Statistical Methods − Biometris, Wageningen University & Research, P.O. Box 16, 6700 AA Wageningen, The Netherlands
| | - Cees J. N. Buisman
- Environmental
Technology, Wageningen University &
Research, P.O. Box 17, 6700
AA Wageningen, The
Netherlands
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 AD Leeuwarden, The Netherlands
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2
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Ke N, Kumka JE, Fang M, Weaver B, Burstyn JN, Bauer CE. RedB, a Member of the CRP/FNR Family, Functions as a Transcriptional Redox Brake. Microbiol Spectr 2022; 10:e0235322. [PMID: 36106751 PMCID: PMC9603854 DOI: 10.1128/spectrum.02353-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/25/2022] [Indexed: 01/04/2023] Open
Abstract
Phylogenetic and sequence similarity network analyses of the CRP (cyclic AMP receptor protein)/FNR (fumarate and nitrate reductase regulatory protein) family of transcription factors indicate the presence of numerous subgroups, many of which have not been analyzed. Five homologs of the CRP/FNR family are present in the Rhodobacter capsulatus genome. One is a member of a broadly disseminated, previously uncharacterized CRP/FNR family subgroup encoded by the gene rcc01561. In this study, we utilize mutational disruption, transcriptome sequencing (RNA-seq), and chromatin immunoprecipitation sequencing (ChIP-seq) to determine the role of RCC01561 in regulating R. capsulatus physiology. This analysis shows that a mutant strain disrupted for rcc01561 exhibits altered expression of 451 genes anaerobically. A detailed analysis of the affected loci shows that RCC01561 represses photosynthesis and favors catabolism over anabolism and the use of the Entner-Doudoroff shunt and glycolysis over that of the tricarboxylic acid (TCA) cycle to limit NADH and ATP formation. This newly characterized CRP/FNR family member with a predominant role in reducing the production of reducing potential and ATP is given the nomenclature RedB as it functions as an energy and redox brake. Beyond limiting energy production, RedB also represses the expression of numerous genes involved in protein synthesis, including those involved in translation initiation, tRNA synthesis and charging, and amino acid biosynthesis. IMPORTANCE CRP and FNR are well-characterized members of the CRP/FNR family of regulatory proteins that function to maximize cellular energy production. In this study, we identify several new subgroups of the CRP/FNR family, many of which have not yet been characterized. Using Rhodobacter capsulatus as a model, we have mutationally disrupted the gene rcc01561, which codes for a transcription factor that is a member of a unique subgroup of the CRP/FNR family. Transcriptomic analysis shows that the disruption of rcc01561 leads to the altered expression of 451 genes anaerobically. Analysis of these regulated genes indicates that RCC01561 has a novel role in limiting cellular energy production. To our knowledge, this is first example of a member of the CRP/FNR family that functions as a brake on cellular energy production.
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Affiliation(s)
- Nijia Ke
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Joseph E. Kumka
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Mingxu Fang
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Brian Weaver
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Carl E. Bauer
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
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3
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Shimizu T, Masuda S. Persulphide-responsive transcriptional regulation and metabolism in bacteria. J Biochem 2020; 167:125-132. [PMID: 31385583 DOI: 10.1093/jb/mvz063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/02/2019] [Indexed: 12/17/2022] Open
Abstract
Hydrogen sulphide (H2S) impacts on bacterial growth both positively and negatively; it is utilized as an electron donor for photosynthesis and respiration, and it inactivates terminal oxidases and iron-sulphur clusters. Therefore, bacteria have evolved H2S-responsive detoxification mechanisms for survival. Sulphur assimilation in bacteria has been well studied, and sulphide:quinone oxidoreductase, persulphide dioxygenase, rhodanese and sulphite oxidase were reported as major sulphide-oxidizing enzymes of sulphide assimilation and detoxification pathways. However, how bacteria sense sulphide availability to control H2S and sulphide metabolism remains largely unknown. Recent studies have identified several bacterial (per)sulphide-sensitive transcription factors that change DNA-binding affinity through persulphidation of specific cysteine residues in response to highly reactive sulphur-containing chemicals and reactive sulphur species (RSS). This review focuses on current understanding of the persulphide-responsive transcription factors and RSS metabolism regulated by RSS sensory proteins.
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Affiliation(s)
- Takayuki Shimizu
- Department of General Systems Studies, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komana, Meguro-ku, Tokyo 153-8902, Japan
| | - Shinji Masuda
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
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Koziaeva V, Dziuba M, Leão P, Uzun M, Krutkina M, Grouzdev D. Genome-Based Metabolic Reconstruction of a Novel Uncultivated Freshwater Magnetotactic coccus " Ca. Magnetaquicoccus inordinatus" UR-1, and Proposal of a Candidate Family " Ca. Magnetaquicoccaceae". Front Microbiol 2019; 10:2290. [PMID: 31632385 PMCID: PMC6783814 DOI: 10.3389/fmicb.2019.02290] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/19/2019] [Indexed: 12/20/2022] Open
Abstract
Magnetotactic bacteria are widely represented microorganisms that have the ability to synthesize magnetosomes. The magnetotactic cocci of the order Magnetococcales are the most frequently identified, but their classification remains unclear due to the low number of cultivated representatives. This paper reports the analysis of an uncultivated magnetotactic coccus UR-1 collected from the Uda River (in eastern Siberia). Genome analyses of this bacterium and comparison to the available Magnetococcales genomes identified a novel species called "Ca. Magnetaquicoccus inordinatus," and a delineated candidate family "Ca. Magnetaquicoccaceae" within the order Magnetococcales is proposed. We used average amino acid identity values <55-56% and <64-65% as thresholds for the separation of families and genera, respectively, within the order Magnetococcales. Analyses of the genome sequence of UR-1 revealed a potential ability for a chemolithoautotrophic lifestyle, with the oxidation of a reduced sulfur compound and carbon assimilation by rTCA. A nearly complete magnetosome genome island, containing a set of mam and mms genes, was also identified. Further comparative analyses of the magnetosome genes showed vertical inheritance as well as horizontal gene transfer as the evolutionary drivers of magnetosome biomineralization genes in strains of the order Magnetococcales.
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Affiliation(s)
- Veronika Koziaeva
- Research Center of Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Moscow, Russia
| | - Marina Dziuba
- Research Center of Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Moscow, Russia
- Department of Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Pedro Leão
- Instituto de Microbiologia Paulo de Góes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Maria Uzun
- Research Center of Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Maria Krutkina
- Research Center of Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Moscow, Russia
| | - Denis Grouzdev
- Research Center of Biotechnology of the Russian Academy of Sciences, Institute of Bioengineering, Moscow, Russia
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Aerobic Anoxygenic Photosynthesis Is Commonly Present within the Genus Limnohabitans. Appl Environ Microbiol 2017; 84:AEM.02116-17. [PMID: 29030444 DOI: 10.1128/aem.02116-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 10/07/2017] [Indexed: 11/20/2022] Open
Abstract
The genus Limnohabitans (Comamonadaceae, Betaproteobacteria) is a common and a highly active component of freshwater bacterioplanktonic communities. To date, the genus has been considered to contain only heterotrophic species. In this study, we detected the photosynthesis genes pufLM and bchY in 28 of 46 strains from three Limnohabitans lineages. The pufM sequences obtained are very closely related to environmental pufM sequences detected in various freshwater habitats, indicating the ubiquity and potential importance of photoheterotrophic Limnohabitans in nature. Additionally, we sequenced and analyzed the genomes of 5 potentially photoheterotrophic Limnohabitans strains, to gain further insights into their phototrophic capacity. The structure of the photosynthesis gene cluster turned out to be highly conserved within the genus Limnohabitans and also among all potentially photosynthetic Betaproteobacteria strains. The expression of photosynthetic complexes was detected in a culture of Limnohabitans planktonicus II-D5T using spectroscopic and pigment analyses. This was further verified by a novel combination of infrared microscopy and fluorescent in situ hybridization.IMPORTANCE The data presented document that the capacity to perform anoxygenic photosynthesis is common among the members of the genus Limnohabitans, indicating that they may have a novel role in freshwater habitats.
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Danial AW, Abdel Wahab AM, Arafat HH, Abdel-Basset R. Bioenergetics of lactate vs. acetate outside TCA enhanced the hydrogen evolution levels in two newly isolated strains of the photosynthetic bacterium Rhodopseudomonas. ACTA ACUST UNITED AC 2017; 72:99-105. [PMID: 28121619 DOI: 10.1515/znc-2016-0070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 12/31/2016] [Indexed: 11/15/2022]
Abstract
Two local hydrogen-evolving strains of purple nonsulfur bacteria have been isolated, characterized, and identified as Rhodopseudomonas sp. TUT (strains Rh1 and Rh2). Lactate followed by succinate and malate supported the highest amounts of H2 production, growth (O.D.660nm, proteins and bacteriochlorphyll contents), nitrogenase activity, and uptake hydrogenase; the least of which was acetate. Alginate-immobilized cells evolved higher hydrogen amounts than free cell counterparts. Rh1 was more productive than Rh2 at all circumstances. Lactate-dependent hydrogen evolution was more than twice that of acetate, due to ATP productivity (2/-1, respectively), which is limiting to the nitrogenase activity. The preference of lactate over other acids indicates the feasibility of using these two strains in hydrogen production from dairy wastewater.
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Affiliation(s)
- Amal W Danial
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, Egypt
| | - Ahmed M Abdel Wahab
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, Egypt
| | - Houssam H Arafat
- Botany and Microbiology Department, Faculty of Science, Menia University, Menia, Egypt
| | - Refat Abdel-Basset
- Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut, Egypt, Phone: 00201010890861, Fax: 0020 88 2342708
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Findlay AJ. Microbial impact on polysulfide dynamics in the environment. FEMS Microbiol Lett 2016; 363:fnw103. [DOI: 10.1093/femsle/fnw103] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2016] [Indexed: 11/12/2022] Open
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8
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Sipkema D, de Caralt S, Morillo JA, Al-Soud WA, Sørensen SJ, Smidt H, Uriz MJ. Similar sponge-associated bacteria can be acquired via both vertical and horizontal transmission. Environ Microbiol 2015; 17:3807-21. [PMID: 25732544 DOI: 10.1111/1462-2920.12827] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 02/19/2015] [Accepted: 02/22/2015] [Indexed: 11/29/2022]
Abstract
Marine sponges host diverse communities of microorganisms that are often vertically transmitted from mother to oocyte or embryo. Horizontal transmission has often been proposed to co-occur in marine sponges, but the mechanism is poorly understood. To assess the impact of the mode of transmission on the microbial assemblages of sponges, we analysed the microbiota in sympatric sponges that have previously been reported to acquire bacteria via either vertical (Corticium candelabrum and Crambe crambe) or horizontal transmission (Petrosia ficiformis). The comparative study was performed by polymerase chain reaction-denaturing gradient gel electrophoresis and pyrosequencing of barcoded PCR-amplified 16S rRNA gene fragments. We found that P. ficiformis and C. candelabrum each harbour their own species-specific bacteria, but they are similar to other high-microbial-abundance sponges, while the low-microbial-abundance sponge C. crambe hosts microbiota of a very different phylogenetic signature. In addition, nearly 50% of the reads obtained from P. ficiformis were most closely related to bacteria that were previously reported to be vertically transmitted in other sponges and comprised vertical-horizontal transmission phylogenetic clusters (VHT clusters). Therefore, our results provide evidence for the hypothesis that similar sponge-associated bacteria can be acquired via both vertical and horizontal transmission.
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Affiliation(s)
- Detmer Sipkema
- Centre d'Estudis Avançats de Blanes (CEAB), CSIC, Accés a la Cala Sant Francesc 14, 17300, Blanes, Spain.,Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands
| | - Sònia de Caralt
- Centre d'Estudis Avançats de Blanes (CEAB), CSIC, Accés a la Cala Sant Francesc 14, 17300, Blanes, Spain
| | - Jose A Morillo
- Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands.,Institute of Water Research, Department of Microbiology, University of Granada, c/Ramon y Cajal 4, 18071, Granada, Spain
| | - Waleed Abu Al-Soud
- Molecular Microbial Ecology Group, University of Copenhagen, Sølvgade 83H, 1307K, Copenhagen, Denmark
| | - Søren J Sørensen
- Molecular Microbial Ecology Group, University of Copenhagen, Sølvgade 83H, 1307K, Copenhagen, Denmark
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands
| | - María J Uriz
- Centre d'Estudis Avançats de Blanes (CEAB), CSIC, Accés a la Cala Sant Francesc 14, 17300, Blanes, Spain
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Denkmann K, Grein F, Zigann R, Siemen A, Bergmann J, van Helmont S, Nicolai A, Pereira IAC, Dahl C. Thiosulfate dehydrogenase: a widespread unusual acidophilicc-type cytochrome. Environ Microbiol 2012; 14:2673-88. [DOI: 10.1111/j.1462-2920.2012.02820.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Grimm F, Dobler N, Dahl C. Regulation of dsr genes encoding proteins responsible for the oxidation of stored sulfur in Allochromatium vinosum. MICROBIOLOGY-SGM 2009; 156:764-773. [PMID: 20007651 DOI: 10.1099/mic.0.034645-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Sulfur globules are formed as obligatory intermediates during the oxidation of reduced sulfur compounds in many environmentally important photo- and chemolithoautotrophic bacteria. It is well established that the so-called Dsr proteins are essential for the oxidation of zero-valent sulfur accumulated in the globules; however, hardly anything is known about the regulation of dsr gene expression. Here, we present a closer look at the regulation of the dsr genes in the phototrophic sulfur bacterium Allochromatium vinosum. The dsr genes are expressed in a reduced sulfur compound-dependent manner and neither sulfite, the product of the reverse-acting dissimilatory sulfite reductase DsrAB, nor the alternative electron donor malate inhibit the gene expression. Moreover, we show the oxidation of sulfur to sulfite to be the rate-limiting step in the oxidation of sulfur to sulfate as sulfate production starts concomitantly with the upregulation of the expression of the dsr genes. Real-time RT-PCR experiments suggest that the genes dsrC and dsrS are additionally expressed from secondary internal promoters, pointing to a special function of the encoded proteins. Earlier structural analyses indicated the presence of a helix-turn-helix (HTH)-like motif in DsrC. We therefore assessed the DNA-binding capability of the protein and provide evidence for a possible regulatory function of DsrC.
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Affiliation(s)
- Frauke Grimm
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
| | - Nadine Dobler
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
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Ghosh W, Dam B. Biochemistry and molecular biology of lithotrophic sulfur oxidation by taxonomically and ecologically diverse bacteria and archaea. FEMS Microbiol Rev 2009; 33:999-1043. [PMID: 19645821 DOI: 10.1111/j.1574-6976.2009.00187.x] [Citation(s) in RCA: 284] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Lithotrophic sulfur oxidation is an ancient metabolic process. Ecologically and taxonomically diverged prokaryotes have differential abilities to utilize different reduced sulfur compounds as lithotrophic substrates. Different phototrophic or chemotrophic species use different enzymes, pathways and mechanisms of electron transport and energy conservation for the oxidation of any given substrate. While the mechanisms of sulfur oxidation in obligately chemolithotrophic bacteria, predominantly belonging to Beta- (e.g. Thiobacillus) and Gammaproteobacteria (e.g. Thiomicrospira), are not well established, the Sox system is the central pathway in the facultative bacteria from Alphaproteobacteria (e.g. Paracoccus). Interestingly, photolithotrophs such as Rhodovulum belonging to Alphaproteobacteria also use the Sox system, whereas those from Chromatiaceae and Chlorobi use a truncated Sox complex alongside reverse-acting sulfate-reducing systems. Certain chemotrophic magnetotactic Alphaproteobacteria allegedly utilize such a combined mechanism. Sulfur-chemolithotrophic metabolism in Archaea, largely restricted to Sulfolobales, is distinct from those in Bacteria. Phylogenetic and biomolecular fossil data suggest that the ubiquity of sox genes could be due to horizontal transfer, and coupled sulfate reduction/sulfide oxidation pathways, originating in planktonic ancestors of Chromatiaceae or Chlorobi, could be ancestral to all sulfur-lithotrophic processes. However, the possibility that chemolithotrophy, originating in deep sea, is the actual ancestral form of sulfur oxidation cannot be ruled out.
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Affiliation(s)
- Wriddhiman Ghosh
- Department of Microbiology, University of Burdwan, West Bengal, India.
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