scholarly journals Anoxygenic Photosynthesis in Photolithotrophic Sulfur Bacteria and Their Role in Detoxication of Hydrogen Sulfide

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 829
Author(s):  
Ivan Kushkevych ◽  
Veronika Bosáková ◽  
Monika Vítězová ◽  
Simon K.-M. R. Rittmann
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Sulfide ◽  
Metabolic Process ◽  
Electron Donors ◽  
Reduced Sulfur Compounds ◽  
Anoxygenic Photosynthesis ◽  
Toxic Compound ◽  
Sulfur Bacteria ◽  
Phototrophic Microorganisms ◽  
Inorganic Substrate

Hydrogen sulfide is a toxic compound that can affect various groups of water microorganisms. Photolithotrophic sulfur bacteria including Chromatiaceae and Chlorobiaceae are able to convert inorganic substrate (hydrogen sulfide and carbon dioxide) into organic matter deriving energy from photosynthesis. This process takes place in the absence of molecular oxygen and is referred to as anoxygenic photosynthesis, in which exogenous electron donors are needed. These donors may be reduced sulfur compounds such as hydrogen sulfide. This paper deals with the description of this metabolic process, representatives of the above-mentioned families, and discusses the possibility using anoxygenic phototrophic microorganisms for the detoxification of toxic hydrogen sulfide. Moreover, their general characteristics, morphology, metabolism, and taxonomy are described as well as the conditions for isolation and cultivation of these microorganisms will be presented.

scholarly journals Differential RNA Sequencing Implicates Sulfide as the Master Regulator of S 0 Metabolism in Chlorobaculum tepidum and Other Green Sulfur Bacteria

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Jacob M. Hilzinger ◽  
Vidhyavathi Raman ◽  
Kevin E. Shuman ◽  
Brian J. Eddie ◽  
Thomas E. Hanson
Keyword(s):  
Gene Expression ◽  
Elemental Sulfur ◽  
Green Sulfur Bacteria ◽  
Electron Donors ◽  
Reduced Sulfur Compounds ◽  
Promoter Elements ◽  
Content Type ◽  
Sulfur Bacteria ◽  
Chlorobaculum Tepidum ◽  
Green Sulfur

ABSTRACT The green sulfur bacteria ( Chlorobiaceae ) are anaerobes that use electrons from reduced sulfur compounds (sulfide, S 0 , and thiosulfate) as electron donors for photoautotrophic growth. Chlorobaculum tepidum , the model system for the Chlorobiaceae , both produces and consumes extracellular S 0 globules depending on the availability of sulfide in the environment. These physiological changes imply significant changes in gene regulation, which has been observed when sulfide is added to Cba. tepidum growing on thiosulfate. However, the underlying mechanisms driving these gene expression changes, i.e., the specific regulators and promoter elements involved, have not yet been defined. Here, differential RNA sequencing (dRNA-seq) was used to globally identify transcript start sites (TSS) that were present during growth on sulfide, biogenic S 0 , and thiosulfate as sole electron donors. TSS positions were used in combination with RNA-seq data from cultures growing on these same electron donors to identify both basal promoter elements and motifs associated with electron donor-dependent transcriptional regulation. These motifs were conserved across homologous Chlorobiaceae promoters. Two lines of evidence suggest that sulfide-mediated repression is the dominant regulatory mode in Cba. tepidum . First, motifs associated with genes regulated by sulfide overlap key basal promoter elements. Second, deletion of the Cba. tepidum 1277 ( CT1277 ) gene, encoding a putative regulatory protein, leads to constitutive overexpression of the sulfide:quinone oxidoreductase CT1087 in the absence of sulfide. The results suggest that sulfide is the master regulator of sulfur metabolism in Cba. tepidum and the Chlorobiaceae . Finally, the identification of basal promoter elements with differing strengths will further the development of synthetic biology in Cba. tepidum and perhaps other Chlorobiaceae . IMPORTANCE Elemental sulfur is a key intermediate in biogeochemical sulfur cycling. The photoautotrophic green sulfur bacterium Chlorobaculum tepidum either produces or consumes elemental sulfur depending on the availability of sulfide in the environment. Our results reveal transcriptional dynamics of Chlorobaculum tepidum on elemental sulfur and increase our understanding of the mechanisms of transcriptional regulation governing growth on different reduced sulfur compounds. This report identifies genes and sequence motifs that likely play significant roles in the production and consumption of elemental sulfur. Beyond this focused impact, this report paves the way for the development of synthetic biology in Chlorobaculum tepidum and other Chlorobiaceae by providing a comprehensive identification of promoter elements for control of gene expression, a key element of strain engineering.

scholarly journals “Candidatus Chlorobium masyuteum,” a Novel Photoferrotrophic Green Sulfur Bacterium Enriched From a Ferruginous Meromictic Lake

2021 ◽  
Vol 12 ◽  
Author(s):  
Nicholas Lambrecht ◽  
Zackry Stevenson ◽  
Cody S. Sheik ◽  
Matthew A. Pronschinske ◽  
Hui Tong ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Tca Cycle ◽  
Green Sulfur Bacteria ◽  
Sulfur Compounds ◽  
Electron Donors ◽  
Anoxygenic Phototrophic Bacteria ◽  
Reduced Sulfur Compounds ◽  
Sulfur Bacteria ◽  
Green Sulfur ◽  
Reduced Sulfur

Anoxygenic phototrophic bacteria can be important primary producers in some meromictic lakes. Green sulfur bacteria (GSB) have been detected in ferruginous lakes, with some evidence that they are photosynthesizing using Fe(II) as an electron donor (i.e., photoferrotrophy). However, some photoferrotrophic GSB can also utilize reduced sulfur compounds, complicating the interpretation of Fe-dependent photosynthetic primary productivity. An enrichment (BLA1) from meromictic ferruginous Brownie Lake, Minnesota, United States, contains an Fe(II)-oxidizing GSB and a metabolically flexible putative Fe(III)-reducing anaerobe. “Candidatus Chlorobium masyuteum” grows photoautotrophically with Fe(II) and possesses the putative Fe(II) oxidase-encoding cyc2 gene also known from oxygen-dependent Fe(II)-oxidizing bacteria. It lacks genes for oxidation of reduced sulfur compounds. Its genome encodes for hydrogenases and a reverse TCA cycle that may allow it to utilize H2 and acetate as electron donors, an inference supported by the abundance of this organism when the enrichment was supplied by these substrates and light. The anaerobe “Candidatus Pseudopelobacter ferreus” is in low abundance (∼1%) in BLA1 and is a putative Fe(III)-reducing bacterium from the Geobacterales ord. nov. While “Ca. C. masyuteum” is closely related to the photoferrotrophs C. ferroooxidans strain KoFox and C. phaeoferrooxidans strain KB01, it is unique at the genomic level. The main light-harvesting molecule was identified as bacteriochlorophyll c with accessory carotenoids of the chlorobactene series. BLA1 optimally oxidizes Fe(II) at a pH of 6.8, and the rate of Fe(II) oxidation was 0.63 ± 0.069 mmol day–1, comparable to other photoferrotrophic GSB cultures or enrichments. Investigation of BLA1 expands the genetic basis for phototrophic Fe(II) oxidation by GSB and highlights the role these organisms may play in Fe(II) oxidation and carbon cycling in ferruginous lakes.

scholarly journals dRNA-seq implicates sulfide as master regulator of S(0) metabolism in Chlorobaculum tepidum and other green sulfur bacteria

2017 ◽  
Author(s):  
Jacob M. Hilzinger ◽  
Vidhyavathi Raman ◽  
Kevin E. Shuman ◽  
Brian J. Eddie ◽  
Thomas E. Hanson
Keyword(s):  
Gene Expression ◽  
Elemental Sulfur ◽  
Green Sulfur Bacteria ◽  
Electron Donors ◽  
Rna Seq ◽  
Reduced Sulfur Compounds ◽  
Promoter Elements ◽  
Sulfur Bacteria ◽  
Chlorobaculum Tepidum ◽  
Green Sulfur

AbstractThe green sulfur bacteria (Chlorobiaceae) are anaerobes that use electrons from reduced sulfur compounds (sulfide, S(0), and thiosulfate) as electron donors for photoautotrophic growth. Chlorobaculum tepidum, the model system for the Chlorobiaceae, both produces and consumes extracellular S(0) globules depending on the availability of sulfide in the environment. These physiological changes imply significant changes in gene regulation, which has been observed when sulfide is added to Cba. tepidum growing on thiosulfate. However, the underlying mechanisms driving these gene expression changes, i.e. specific regulators and promoter elements involved, have not yet been defined. Here, differential RNA-seq (dRNA-seq) was used to globally identify transcript start sites (TSS) that were present during growth on sulfide, biogenic S(0), and thiosulfate as sole electron donors. TSS positions were used in combination with RNA-seq data from cultures growing on these same electron donors to identify both basal promoter elements and motifs associated with electron donor dependent transcriptional regulation. These motifs were conserved across homologous Chlorobiaceae promoters. Two lines of evidence suggest that sulfide mediated repression is the dominant regulatory mode in Cba. tepidum. First, motifs associated with genes regulated by sulfide overlap key basal promoter elements. Second, deletion of the gene CT1277, encoding a putative regulatory protein, leads to constitutive over-expression of the sulfide:quinone oxidoreductase CT1087 in the absence of sulfide. The results suggest that sulfide is the master regulator of sulfur metabolism in Cba. tepidum and the Chlorobiaceae. Finally, the identification of basal promoter elements with differing strengths will further the development of synthetic biology in Cba. tepidum and perhaps other Chlorobiaceae.ImportanceElemental sulfur is a key intermediate in biogeochemical sulfur cycling. The photoautotrophic green sulfur bacterium Chlorobaculum tepidum both produces and consumes elemental sulfur depending on the availability of sulfide in the environment. Our results reveal transcriptional dynamics of Chlorobaculum tepidum on elemental sulfur, and increase our understanding of the mechanisms of transcriptional regulation governing growth on different reduced sulfur compounds. This study identifies new genes and sequence motifs that likely play significant roles in the production and consumption of elemental sulfur. Beyond this focused impact, this study paves the way for the development of synthetic biology in Chlorobaculum tepidum and other Chlorobiaceae by providing a comprehensive identification of promoter elements to control gene expression, a key element of strain engineering.

scholarly journals Molecular Physiology of Anaerobic Phototrophic Purple and Green Sulfur Bacteria

2021 ◽  
Vol 22 (12) ◽  
pp. 6398
Author(s):  
Ivan Kushkevych ◽  
Jiří Procházka ◽  
Márió Gajdács ◽  
Simon K.-M. R. Rittmann ◽  
Monika Vítězová
Keyword(s):  
Hydrogen Sulfide ◽  
Molecular Mechanisms ◽  
Photosynthetic Apparatus ◽  
Green Sulfur Bacteria ◽  
Bacterial Photosynthesis ◽  
Molecular Physiology ◽  
Physiological Processes ◽  
Sulfur Bacteria ◽  
Phototrophic Microorganisms ◽  
Green Sulfur

There are two main types of bacterial photosynthesis: oxygenic (cyanobacteria) and anoxygenic (sulfur and non-sulfur phototrophs). Molecular mechanisms of photosynthesis in the phototrophic microorganisms can differ and depend on their location and pigments in the cells. This paper describes bacteria capable of molecular oxidizing hydrogen sulfide, specifically the families Chromatiaceae and Chlorobiaceae, also known as purple and green sulfur bacteria in the process of anoxygenic photosynthesis. Further, it analyzes certain important physiological processes, especially those which are characteristic for these bacterial families. Primarily, the molecular metabolism of sulfur, which oxidizes hydrogen sulfide to elementary molecular sulfur, as well as photosynthetic processes taking place inside of cells are presented. Particular attention is paid to the description of the molecular structure of the photosynthetic apparatus in these two families of phototrophs. Moreover, some of their molecular biotechnological perspectives are discussed.

Ammonia and other microclimatic conditions at an Australian pre-export sheep assembly depot

2013 ◽  
Vol 53 (6) ◽  
pp. 580
Author(s):  
Mathew K. Pines ◽  
Tracy Muller ◽  
Clive J. C. Phillips
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Sulfide ◽  
Moisture Content ◽  
Gaseous Emissions ◽  
Housing Systems ◽  
Health And Wellbeing ◽  
Ammonia Accumulation ◽  
Animal Excreta ◽  
Microclimatic Conditions ◽  
Positive Correlations

Noxious gases produced at hazardous concentrations in animal housing systems may affect the health and wellbeing of both animals and workers. In order to determine if the gaseous emissions from a pre-export assembly depot for sheep constituted a risk, atmospheric ammonia was measured in eight sheep buildings at an Australian assembly depot. Additionally, meteorological variables and distance from excreta were measured to determine their influence on ammonia, carbon dioxide and hydrogen sulfide concentrations. Repeat measurements were made at 12 sites in each building on 4 separate days, and four buildings were mapped using longitudinal and latitudinal transects. Concentrations of ammonia, carbon dioxide and hydrogen sulfide were all below the recommended safety thresholds for humans and livestock. There were positive correlations between ammonia and the following variables: ambient temperature and moisture content, and negative correlations with distance from animal excreta. Understanding these relationships will help to understand the reasons for ammonia accumulation in such buildings.

scholarly journals Stan i perspektywy wykorzystania biogazu jako nośnika energii do zastosowań stacjonarnych i środków transportu

2012 ◽  
Vol 10 (3) ◽  
pp. 97-118
Author(s):  
Krzysztof Biernat ◽  
Izabela Różnicka
Keyword(s):  
Carbon Dioxide ◽  
Renewable Energy ◽  
Hydrogen Sulfide ◽  
Energy Balance ◽  
Sewage Sludge ◽  
Motor Fuel ◽  
International Programs ◽  
Biogas Upgrading ◽  
Compressed Natural Gas ◽  
Production Of Hydrogen

Both governmental and international programs support the promotion of biofuels and aim to increase the limit of renewable energy used in the fuel energy balance. Biogas is produced during the anaerobic methane fermentationprocess and it is known as a significant source of renewable energy, contributing to agriculture and environmental protection. Three types of biogas can be distinguished: biogas from sewage sludge, biogas collected from land`fils, andagricultural biogas. There are several possibilities of using upgraded biogas. Biogas can be used in cogeneration systems to provide heat and electricity, in transportation as a motor fuel and in the production of biohydrogen. Biogas upgrading process leads to a product which is characterized by the same parameters as compressed natural gas. Direct biogas use in the production of hydrogen is possible because of prior purification from traces like hydrogen sulfide, except carbon dioxide, by which the reaction can proceed in the desired manner.

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