1
|
Vanyan L, Trchounian K. Glucose concentration is determinant for the functioning of hydrogenase 1 and hydrogenase 2 in regulating the proton and potassium fluxes in Escherichia coli at pH 7.5. Biochimie 2024:S0300-9084(24)00172-X. [PMID: 39038731 DOI: 10.1016/j.biochi.2024.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 07/24/2024]
Abstract
This study examines how FOF1-ATPase, hydrogenases (Hyd-1 and Hyd-2), and potassium transport systems (TrkA) interact to maintain the proton motive force (pmf) in E. coli during fermentation of different glucose concentrations (2 g L-1 and 8 g L-1). Our findings indicate that mutants lacking the hyaA-hyaC genes exhibited a 30 % increase in total proton flux compared to the wild type when grown with 2 g L-1 glucose. This has been observed during assays where similar glucose levels were supplemented. Disruptions in proton pumping, particularly in hyaB and hyaC single mutants, led to increased potassium uptake. The hyaB mutant showed a threefold increase in the contribution of FOF1-ATPase to proton flux, suggesting a significant role for Hyd-1 in proton translocation. In the hybC mutant grown in 2 g L-1 glucose conditions, DCCD-sensitive fluxes decreased by 70 %, indicating critical role of Hyd-2 in proton transport and FOF1 function. When cells were grown with 8 g L-1 glucose, the 2H+/1K+ ratio was significantly disturbed in both wild type and mutants. Despite these perturbances, mutants with disruptions in Hyd-1 and Hyd-2 maintained constant FOF1 function, suggesting that this enzyme remains stable in glucose-rich environments. These results provide valuable insights into how Hyd-1 and Hyd-2 contribute to the regulation of ion transport, particularly proton translocation, in response to glucose concentration. Our study uncovered potential complementary mechanisms between Hyd-1 and Hyd-2 subunits, suggesting a complex interplay between these enzymes via metabolic cross talk with FOF1 in response to glucose concentrations to maintain pmf.
Collapse
Affiliation(s)
- Liana Vanyan
- Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 1 A. Manoogian str., 0025, Yerevan, Armenia; Research Institute of Biology, Yerevan State University, 1 A. Manoogian str., 0025, Yerevan, Armenia; Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 1 A. Manoogian str., 0025, Yerevan, Armenia
| | - Karen Trchounian
- Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 1 A. Manoogian str., 0025, Yerevan, Armenia; Research Institute of Biology, Yerevan State University, 1 A. Manoogian str., 0025, Yerevan, Armenia; Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 1 A. Manoogian str., 0025, Yerevan, Armenia.
| |
Collapse
|
2
|
Sapountzaki E, Rova U, Christakopoulos P, Antonopoulou I. Renewable Hydrogen Production and Storage Via Enzymatic Interconversion of CO 2 and Formate with Electrochemical Cofactor Regeneration. CHEMSUSCHEM 2023; 16:e202202312. [PMID: 37165995 DOI: 10.1002/cssc.202202312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/12/2023]
Abstract
The urgent need to reduce CO2 emissions has motivated the development of CO2 capture and utilization technologies. An emerging application is CO2 transformation into storage chemicals for clean energy carriers. Formic acid (FA), a valuable product of CO2 reduction, is an excellent hydrogen carrier. CO2 conversion to FA, followed by H2 release from FA, are conventionally chemically catalyzed. Biocatalysts offer a highly specific and less energy-intensive alternative. CO2 conversion to formate is catalyzed by formate dehydrogenase (FDH), which usually requires a cofactor to function. Several FDHs have been incorporated in bioelectrochemical systems where formate is produced by the biocathode and the cofactor is electrochemically regenerated. H2 production from formate is also catalyzed by several microorganisms possessing either formate hydrogenlyase or hydrogen-dependent CO2 reductase complexes. Combination of these two processes can lead to a CO2 -recycling cycle for H2 production, storage, and release with potentially lower environmental impact than conventional methods.
Collapse
Affiliation(s)
- Eleftheria Sapountzaki
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden
| | - Io Antonopoulou
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden
| |
Collapse
|
3
|
Nguyen HK, Minato T, Moniruzzaman M, Kiyasu Y, Ogo S, Yoon KS. Selective formate production from H 2 and CO 2 using encapsulated whole-cells under mild reaction conditions. J Biosci Bioeng 2023; 136:182-189. [PMID: 37400329 DOI: 10.1016/j.jbiosc.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 07/05/2023]
Abstract
Biocatalytic CO2 reduction into formate is a crucial strategy for developing clean energy because formate is considered as one of the promising hydrogen storage materials for achieving net-zero carbon emissions. Here, we developed an efficient biocatalytic system to produce formate selectively by coupling two enzymatic activities of H2 oxidation and CO2 reduction using encapsulated bacterial cells of Citrobacter sp. S-77. The encapsulated whole-cell catalyst was made by living cells depositing into polyvinyl alcohol and gellan gum cross-linked by calcium ions to form hydrogel beads. Formate production using encapsulated cells was carried out under the resting state conditions in the gas mixture of H2/CO2 (70:30, v/v%). The whole-cell biocatalyst showed highly efficient and selective catalytic production of formate, reaching the specific rate of formate production of 110 mmol L-1· gprotein-1·h-1 at 30 °C, pH 7.0, and 0.1 MPa. The encapsulated cells can be reused at least 8 times while keeping their high catalytic activities for formate production under mild reaction conditions.
Collapse
Affiliation(s)
- Hung Khac Nguyen
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Japan
| | - Takuo Minato
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Japan; International Institute for Carbon-Neutral Energy Research (WPI-I(2)CNER), Kyushu University, Japan; Department of Applied Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8527, Japan
| | - Mohammad Moniruzzaman
- International Institute for Carbon-Neutral Energy Research (WPI-I(2)CNER), Kyushu University, Japan; Mitsui Chemicals, Inc.- Carbon Neutral Research Center (MCI-CNRC), Kyushu University, Japan
| | - Yu Kiyasu
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Japan
| | - Seiji Ogo
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Japan; International Institute for Carbon-Neutral Energy Research (WPI-I(2)CNER), Kyushu University, Japan; Center for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ki-Seok Yoon
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Japan; International Institute for Carbon-Neutral Energy Research (WPI-I(2)CNER), Kyushu University, Japan; Mitsui Chemicals, Inc.- Carbon Neutral Research Center (MCI-CNRC), Kyushu University, Japan.
| |
Collapse
|
4
|
Saxena P, Rauniyar S, Thakur P, Singh RN, Bomgni A, Alaba MO, Tripathi AK, Gnimpieba EZ, Lushbough C, Sani RK. Integration of text mining and biological network analysis: Identification of essential genes in sulfate-reducing bacteria. Front Microbiol 2023; 14:1086021. [PMID: 37125195 PMCID: PMC10133479 DOI: 10.3389/fmicb.2023.1086021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/23/2023] [Indexed: 05/02/2023] Open
Abstract
The growth and survival of an organism in a particular environment is highly depends on the certain indispensable genes, termed as essential genes. Sulfate-reducing bacteria (SRB) are obligate anaerobes which thrives on sulfate reduction for its energy requirements. The present study used Oleidesulfovibrio alaskensis G20 (OA G20) as a model SRB to categorize the essential genes based on their key metabolic pathways. Herein, we reported a feedback loop framework for gene of interest discovery, from bio-problem to gene set of interest, leveraging expert annotation with computational prediction. Defined bio-problem was applied to retrieve the genes of SRB from literature databases (PubMed, and PubMed Central) and annotated them to the genome of OA G20. Retrieved gene list was further used to enrich protein-protein interaction and was corroborated to the pangenome analysis, to categorize the enriched gene sets and the respective pathways under essential and non-essential. Interestingly, the sat gene (dde_2265) from the sulfur metabolism was the bridging gene between all the enriched pathways. Gene clusters involved in essential pathways were linked with the genes from seleno-compound metabolism, amino acid metabolism, secondary metabolite synthesis, and cofactor biosynthesis. Furthermore, pangenome analysis demonstrated the gene distribution, where 69.83% of the 116 enriched genes were mapped under "persistent," inferring the essentiality of these genes. Likewise, 21.55% of the enriched genes, which involves specially the formate dehydrogenases and metallic hydrogenases, appeared under "shell." Our methodology suggested that semi-automated text mining and network analysis may play a crucial role in deciphering the previously unexplored genes and key mechanisms which can help to generate a baseline prior to perform any experimental studies.
Collapse
Affiliation(s)
- Priya Saxena
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Shailabh Rauniyar
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Payal Thakur
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Ram Nageena Singh
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Alain Bomgni
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
| | - Mathew O. Alaba
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
| | - Abhilash Kumar Tripathi
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
| | - Etienne Z. Gnimpieba
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
- *Correspondence: Etienne Z. Gnimpieba,
| | - Carol Lushbough
- Department of Biomedical Engineering, University of South Dakota, Sioux Falls, SD, United States
| | - Rajesh Kumar Sani
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, SD, United States
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, SD, United States
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD, United States
- Rajesh Kumar Sani,
| |
Collapse
|
5
|
Formate hydrogenlyase, formic acid translocation and hydrogen production: dynamic membrane biology during fermentation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148919. [PMID: 36152681 DOI: 10.1016/j.bbabio.2022.148919] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/19/2022] [Accepted: 09/19/2022] [Indexed: 12/14/2022]
Abstract
Formate hydrogenlyase-1 (FHL-1) is a complex-I-like enzyme that is commonly found in gram-negative bacteria. The enzyme comprises a peripheral arm and a membrane arm but is not involved in quinone reduction. Instead, FHL-1 couples formate oxidation to the reduction of protons to molecular hydrogen (H2). Escherichia coli produces FHL-1 under fermentative conditions where it serves to detoxify formic acid in the environment. The membrane biology and bioenergetics surrounding E. coli FHL-1 have long held fascination. Here, we review recent work on understanding the molecular basis of formic acid efflux and influx. We also consider the structure and function of E. coli FHL-1, its relationship with formate transport, and pay particular attention to the molecular interface between the peripheral arm and the membrane arm. Finally, we highlight the interesting phenotype of genetic mutation of the ND1 Loop, which is located at that interface.
Collapse
|
6
|
Abstract
Covering: up to 2022The report provides a broad approach to deciphering the evolution of coenzyme biosynthetic pathways. Here, these various pathways are analyzed with respect to the coenzymes required for this purpose. Coenzymes whose biosynthesis relies on a large number of coenzyme-mediated reactions probably appeared on the scene at a later stage of biological evolution, whereas the biosyntheses of pyridoxal phosphate (PLP) and nicotinamide (NAD+) require little additional coenzymatic support and are therefore most likely very ancient biosynthetic pathways.
Collapse
Affiliation(s)
- Andreas Kirschning
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, D-30167 Hannover, Germany.
| |
Collapse
|
7
|
Graham JE, Niks D, Zane GM, Gui Q, Hom K, Hille R, Wall JD, Raman CS. How a Formate Dehydrogenase Responds to Oxygen: Unexpected O 2 Insensitivity of an Enzyme Harboring Tungstopterin, Selenocysteine, and [4Fe–4S] Clusters. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joel E. Graham
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland21201, United States
| | - Dimitri Niks
- Department of Biochemistry, University of California, Riverside, California92521, United States
| | - Grant M. Zane
- Department of Biochemistry, University of Missouri, Columbia, Missouri65211, United States
| | - Qin Gui
- Department of Biochemistry, University of Missouri, Columbia, Missouri65211, United States
| | - Kellie Hom
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland21201, United States
| | - Russ Hille
- Department of Biochemistry, University of California, Riverside, California92521, United States
| | - Judy D. Wall
- Department of Biochemistry, University of Missouri, Columbia, Missouri65211, United States
| | - C. S. Raman
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland21201, United States
| |
Collapse
|
8
|
Reji L, Cardarelli EL, Boye K, Bargar JR, Francis CA. Diverse ecophysiological adaptations of subsurface Thaumarchaeota in floodplain sediments revealed through genome-resolved metagenomics. THE ISME JOURNAL 2022; 16:1140-1152. [PMID: 34873295 PMCID: PMC8940955 DOI: 10.1038/s41396-021-01167-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 11/17/2021] [Accepted: 11/26/2021] [Indexed: 02/03/2023]
Abstract
The terrestrial subsurface microbiome contains vastly underexplored phylogenetic diversity and metabolic novelty, with critical implications for global biogeochemical cycling. Among the key microbial inhabitants of subsurface soils and sediments are Thaumarchaeota, an archaeal phylum that encompasses ammonia-oxidizing archaea (AOA) as well as non-ammonia-oxidizing basal lineages. Thaumarchaeal ecology in terrestrial systems has been extensively characterized, particularly in the case of AOA. However, there is little knowledge on the diversity and ecophysiology of Thaumarchaeota in deeper soils, as most lineages, particularly basal groups, remain uncultivated and underexplored. Here we use genome-resolved metagenomics to examine the phylogenetic and metabolic diversity of Thaumarchaeota along a 234 cm depth profile of hydrologically variable riparian floodplain sediments in the Wind River Basin near Riverton, Wyoming. Phylogenomic analysis of the metagenome-assembled genomes (MAGs) indicates a shift in AOA population structure from the dominance of the terrestrial Nitrososphaerales lineage in the well-drained top ~100 cm of the profile to the typically marine Nitrosopumilales in deeper, moister, more energy-limited sediment layers. We also describe two deeply rooting non-AOA MAGs with numerous unexpected metabolic features, including the reductive acetyl-CoA (Wood-Ljungdahl) pathway, tetrathionate respiration, a form III RuBisCO, and the potential for extracellular electron transfer. These MAGs also harbor tungsten-containing aldehyde:ferredoxin oxidoreductase, group 4f [NiFe]-hydrogenases and a canonical heme catalase, typically not found in Thaumarchaeota. Our results suggest that hydrological variables, particularly proximity to the water table, impart a strong control on the ecophysiology of Thaumarchaeota in alluvial sediments.
Collapse
Affiliation(s)
- Linta Reji
- grid.168010.e0000000419368956Department of Earth System Science, Stanford University, Stanford, CA USA ,grid.16750.350000 0001 2097 5006Present Address: Department of Geosciences, Princeton University, Princeton, NJ USA
| | - Emily L. Cardarelli
- grid.168010.e0000000419368956Department of Earth System Science, Stanford University, Stanford, CA USA ,grid.20861.3d0000000107068890Present Address: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Kristin Boye
- grid.445003.60000 0001 0725 7771Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA USA
| | - John R. Bargar
- grid.445003.60000 0001 0725 7771Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA USA
| | - Christopher A. Francis
- grid.168010.e0000000419368956Department of Earth System Science, Stanford University, Stanford, CA USA
| |
Collapse
|
9
|
Metcalfe GD, Sargent F, Hippler M. Hydrogen production in the presence of oxygen by Escherichia coli K-12. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35343886 PMCID: PMC9558352 DOI: 10.1099/mic.0.001167] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Escherichia coli is a facultative anaerobe that can grow in a variety of environmental conditions. In the complete absence of O2, E. coli can perform a mixed-acid fermentation that contains within it an elaborate metabolism of formic acid. In this study, we use cavity-enhanced Raman spectroscopy (CERS), FTIR, liquid Raman spectroscopy, isotopic labelling and molecular genetics to make advances in the understanding of bacterial formate and H2 metabolism. It is shown that, under anaerobic (anoxic) conditions, formic acid is generated endogenously, excreted briefly from the cell, and then taken up again to be disproportionated to H2 and CO2 by formate hydrogenlyase (FHL-1). However, exogenously added D-labelled formate behaves quite differently from the endogenous formate and is taken up immediately, independently, and possibly by a different mechanism, by the cell and converted to H2 and CO2. Our data support an anion-proton symport model for formic acid transport. In addition, when E. coli was grown in a micro-aerobic (micro-oxic) environment it was possible to analyse aspects of formate and O2 respiration occurring alongside anaerobic metabolism. While cells growing under micro-aerobic conditions generated endogenous formic acid, no H2 was produced. However, addition of exogenous formate at the outset of cell growth did induce FHL-1 biosynthesis and resulted in formate-dependent H2 production in the presence of O2.
Collapse
Affiliation(s)
- George D Metcalfe
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - Frank Sargent
- School of Natural & Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Michael Hippler
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| |
Collapse
|
10
|
Allochromatium tepidum, sp. nov., a hot spring species of purple sulfur bacteria. Arch Microbiol 2022; 204:115. [PMID: 34984587 DOI: 10.1007/s00203-021-02715-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/16/2021] [Accepted: 11/18/2021] [Indexed: 12/30/2022]
Abstract
We describe a new species of purple sulfur bacteria (Chromatiaceae, anoxygenic phototrophic bacteria) isolated from a microbial mat in the sulfidic geothermal outflow of a hot spring in Rotorua, New Zealand. This phototroph, designated as strain NZ, grew optimally near 45 °C but did not show an absorption maximum at 915 nm for the light-harvesting-reaction center core complex (LH1-RC) characteristic of other thermophilic purple sulfur bacteria. Strain NZ had a similar carotenoid composition as Thermochromatium tepidum, but unlike Tch. tepidum, grew photoheterotrophically on acetate in the absence of sulfide and metabolized thiosulfate. The genome of strain NZ was significantly larger than that of Tch. tepidum but slightly smaller than that of Allochromatium vinosum. Strain NZ was phylogenetically more closely related to mesophilic purple sulfur bacteria of the genus Allochromatium than to Tch. tepidum. This conclusion was reached from phylogenetic analyses of strain NZ genes encoding 16S rRNA and the photosynthetic functional gene pufM, from phylogenetic analyses of entire genomes, and from a phylogenetic tree constructed from the concatenated sequence of 1090 orthologous proteins. Moreover, average nucleotide identities and digital DNA:DNA hybridizations of the strain NZ genome against those of related species of Chromatiaceae supported the phylogenetic analyses. From this collection of properties, we describe strain NZ here as the first thermophilic species of the genus Allochromatium, Allochromatium tepidum NZT, sp. nov.
Collapse
|
11
|
Harnessing Escherichia coli for Bio-Based Production of Formate under Pressurized H 2 and CO 2 Gases. Appl Environ Microbiol 2021; 87:e0029921. [PMID: 34647819 DOI: 10.1128/aem.00299-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Escherichia coli is a Gram-negative bacterium that is a workhorse for biotechnology. The organism naturally performs a mixed-acid fermentation under anaerobic conditions where it synthesizes formate hydrogenlyase (FHL-1). The physiological role of the enzyme is the disproportionation of formate into H2 and CO2. However, the enzyme has been observed to catalyze hydrogenation of CO2 given the correct conditions, and so it has possibilities in bio-based carbon capture and storage if it can be harnessed as a hydrogen-dependent CO2 reductase (HDCR). In this study, an E. coli host strain was engineered for the continuous production of formic acid from H2 and CO2 during bacterial growth in a pressurized batch bioreactor. Incorporation of tungsten, in place of molybdenum, in FHL-1 helped to impose a degree of catalytic bias on the enzyme. This work demonstrates that it is possible to couple cell growth to simultaneous, unidirectional formate production from carbon dioxide and develops a process for growth under pressurized gases. IMPORTANCE Greenhouse gas emissions, including waste carbon dioxide, are contributing to global climate change. A basket of solutions is needed to steadily reduce emissions, and one approach is bio-based carbon capture and storage. Here, we present our latest work on harnessing a novel biological solution for carbon capture. The Escherichia coli formate hydrogenlyase (FHL-1) was engineered to be constitutively expressed. Anaerobic growth under pressurized H2 and CO2 gases was established, and aqueous formic acid was produced as a result. Incorporation of tungsten into the enzyme in place of molybdenum proved useful in poising FHL-1 as a hydrogen-dependent CO2 reductase (HDCR).
Collapse
|
12
|
George AS, Rehfuss MYM, Parker CT, Brandl MT. The transcriptome of Escherichia coli O157: H7 reveals a role for oxidative stress resistance in its survival from predation by Tetrahymena. FEMS Microbiol Ecol 2020; 96:5721237. [PMID: 32009174 DOI: 10.1093/femsec/fiaa014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 11/14/2022] Open
Abstract
Pathogenic E. coli remains undigested upon phagocytosis by Tetrahymena and is egested from the ciliate as viable cells in its fecal pellets. Factors that are involved in the survival of Shiga toxin-producing E. coli serovar O157: H7 (EcO157) from digestion by Tetrahymena were identified by microarray analysis of its transcriptome in the protozoan phagosome. Numerous genes belonging to anaerobic metabolism and various stress responses were upregulated significantly ≥ 2-fold in EcO157 cells in the food vacuoles compared with in planktonic cells that remained uningested by the protist. Among these were the oxidative stress response genes, ahpF and katG. Fluorescence microscopy and staining with CellROX® Orange confirmed the presence of reactive oxygen species in food vacuoles containing EcO157 cells. Frequency distribution analysis of the percentage of EcO157 viable cells in Tetrahymena fecal pellets revealed that the ΔahpCF and ΔahpCFΔkatG mutants were less fit than the wild type strain and ΔkatG mutant after passage through the protist. Given the broad use of oxidants as sanitizers in the food industry, our observation of the oxidative stress response in EcO157 during its interaction with Tetrahymena emphasizes the importance of furthering our knowledge of the physiology of this human pathogen in environments relevant to its ecology and to food safety.
Collapse
Affiliation(s)
- Andree Sherlon George
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Marc Yi Ming Rehfuss
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Craig Thomas Parker
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Maria Theresa Brandl
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| |
Collapse
|
13
|
Abstract
How microbial metabolism is translated into cellular reproduction under energy-limited settings below the seafloor over long timescales is poorly understood. Here, we show that microbial abundance increases an order of magnitude over a 5 million-year-long sequence in anoxic subseafloor clay of the abyssal North Atlantic Ocean. This increase in biomass correlated with an increased number of transcribed protein-encoding genes that included those involved in cytokinesis, demonstrating that active microbial reproduction outpaces cell death in these ancient sediments. Metagenomes, metatranscriptomes, and 16S rRNA gene sequencing all show that the actively reproducing community was dominated by the candidate phylum "Candidatus Atribacteria," which exhibited patterns of gene expression consistent with fermentative, and potentially acetogenic, metabolism. "Ca. Atribacteria" dominated throughout the 8 million-year-old cored sequence, despite the detection limit for gene expression being reached in 5 million-year-old sediments. The subseafloor reproducing "Ca. Atribacteria" also expressed genes encoding a bacterial microcompartment that has potential to assist in secondary fermentation by recycling aldehydes and, thereby, harness additional power to reduce ferredoxin and NAD+ Expression of genes encoding the Rnf complex for generation of chemiosmotic ATP synthesis were also detected from the subseafloor "Ca Atribacteria," as well as the Wood-Ljungdahl pathway that could potentially have an anabolic or catabolic function. The correlation of this metabolism with cytokinesis gene expression and a net increase in biomass over the million-year-old sampled interval indicates that the "Ca Atribacteria" can perform the necessary catabolic and anabolic functions necessary for cellular reproduction, even under energy limitation in millions-of-years-old anoxic sediments.IMPORTANCE The deep subseafloor sedimentary biosphere is one of the largest ecosystems on Earth, where microbes subsist under energy-limited conditions over long timescales. It remains poorly understood how mechanisms of microbial metabolism promote increased fitness in these settings. We discovered that the candidate bacterial phylum "Candidatus Atribacteria" dominated a deep-sea subseafloor ecosystem, where it exhibited increased transcription of genes associated with acetogenic fermentation and reproduction in million-year-old sediment. We attribute its improved fitness after burial in the seabed to its capabilities to derive energy from increasingly oxidized metabolites via a bacterial microcompartment and utilize a potentially reversible Wood-Ljungdahl pathway to help meet anabolic and catabolic requirements for growth. Our findings show that "Ca Atribacteria" can perform all the necessary catabolic and anabolic functions necessary for cellular reproduction, even under energy limitation in anoxic sediments that are millions of years old.
Collapse
|
14
|
Finney AJ, Buchanan G, Palmer T, Coulthurst SJ, Sargent F. Activation of a [NiFe]-hydrogenase-4 isoenzyme by maturation proteases. MICROBIOLOGY (READING, ENGLAND) 2020; 166:854-860. [PMID: 32731905 PMCID: PMC7654741 DOI: 10.1099/mic.0.000963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 07/22/2020] [Indexed: 12/23/2022]
Abstract
Maturation of [NiFe]-hydrogenases often involves specific proteases responsible for cleavage of the catalytic subunits. Escherichia coli HycI is the protease dedicated to maturation of the Hydrogenase-3 isoenzyme, a component of formate hydrogenlyase-1. In this work, it is demonstrated that a Pectobacterium atrosepticum HycI homologue, HyfK, is required for hydrogenase-4 activity, a component of formate hydrogenlyase-2, in that bacterium. The P. atrosepticum ΔhyfK mutant phenotype could be rescued by either P. atrosepticum hyfK or E. coli hycI on a plasmid. Conversely, an E. coli ΔhycI mutant was complemented by either E. coli hycI or P. atrosepticum hyfK in trans. E. coli is a rare example of a bacterium containing both hydrogenase-3 and hydrogenase-4, however the operon encoding hydrogenase-4 has no maturation protease gene. This work suggests HycI should be sufficient for maturation of both E. coli formate hydrogenlyases, however no formate hydrogenlyase-2 activity was detected in any E. coli strains tested here.
Collapse
Affiliation(s)
- Alexander J. Finney
- School of Natural & Environmental Sciences, Faculty of Science, Agriculture & Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Grant Buchanan
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
- Institute of Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Tracy Palmer
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
- Institute of Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | | | - Frank Sargent
- School of Natural & Environmental Sciences, Faculty of Science, Agriculture & Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| |
Collapse
|
15
|
Benoit SL, Maier RJ, Sawers RG, Greening C. Molecular Hydrogen Metabolism: a Widespread Trait of Pathogenic Bacteria and Protists. Microbiol Mol Biol Rev 2020; 84:e00092-19. [PMID: 31996394 PMCID: PMC7167206 DOI: 10.1128/mmbr.00092-19] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pathogenic microorganisms use various mechanisms to conserve energy in host tissues and environmental reservoirs. One widespread but often overlooked means of energy conservation is through the consumption or production of molecular hydrogen (H2). Here, we comprehensively review the distribution, biochemistry, and physiology of H2 metabolism in pathogens. Over 200 pathogens and pathobionts carry genes for hydrogenases, the enzymes responsible for H2 oxidation and/or production. Furthermore, at least 46 of these species have been experimentally shown to consume or produce H2 Several major human pathogens use the large amounts of H2 produced by colonic microbiota as an energy source for aerobic or anaerobic respiration. This process has been shown to be critical for growth and virulence of the gastrointestinal bacteria Salmonella enterica serovar Typhimurium, Campylobacter jejuni, Campylobacter concisus, and Helicobacter pylori (including carcinogenic strains). H2 oxidation is generally a facultative trait controlled by central regulators in response to energy and oxidant availability. Other bacterial and protist pathogens produce H2 as a diffusible end product of fermentation processes. These include facultative anaerobes such as Escherichia coli, S Typhimurium, and Giardia intestinalis, which persist by fermentation when limited for respiratory electron acceptors, as well as obligate anaerobes, such as Clostridium perfringens, Clostridioides difficile, and Trichomonas vaginalis, that produce large amounts of H2 during growth. Overall, there is a rich literature on hydrogenases in growth, survival, and virulence in some pathogens. However, we lack a detailed understanding of H2 metabolism in most pathogens, especially obligately anaerobic bacteria, as well as a holistic understanding of gastrointestinal H2 transactions overall. Based on these findings, we also evaluate H2 metabolism as a possible target for drug development or other therapies.
Collapse
Affiliation(s)
- Stéphane L Benoit
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Robert J Maier
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - R Gary Sawers
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
| |
Collapse
|
16
|
Finney AJ, Lowden R, Fleszar M, Albareda M, Coulthurst SJ, Sargent F. The plant pathogen Pectobacterium atrosepticum contains a functional formate hydrogenlyase-2 complex. Mol Microbiol 2019; 112:1440-1452. [PMID: 31420965 PMCID: PMC7384014 DOI: 10.1111/mmi.14370] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2019] [Indexed: 12/19/2022]
Abstract
Pectobacterium atrosepticum SCRI1043 is a phytopathogenic Gram-negative enterobacterium. Genomic analysis has identified that genes required for both respiration and fermentation are expressed under anaerobic conditions. One set of anaerobically expressed genes is predicted to encode an important but poorly understood membrane-bound enzyme termed formate hydrogenlyase-2 (FHL-2), which has fascinating evolutionary links to the mitochondrial NADH dehydrogenase (Complex I). In this work, molecular genetic and biochemical approaches were taken to establish that FHL-2 is fully functional in P. atrosepticum and is the major source of molecular hydrogen gas generated by this bacterium. The FHL-2 complex was shown to comprise a rare example of an active [NiFe]-hydrogenase-4 (Hyd-4) isoenzyme, itself linked to an unusual selenium-free formate dehydrogenase in the final complex. In addition, further genetic dissection of the genes encoding the predicted membrane arm of FHL-2 established surprisingly that the majority of genes encoding this domain are not required for physiological hydrogen production activity. Overall, this study presents P. atrosepticum as a new model bacterial system for understanding anaerobic formate and hydrogen metabolism in general, and FHL-2 function and structure in particular.
Collapse
Affiliation(s)
- Alexander J Finney
- School of Natural & Environmental Sciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK.,School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Rebecca Lowden
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Michal Fleszar
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Marta Albareda
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.,Centro de Biotecnología y Genómica de Plantas (C.B.G.P.) UPM-INIA, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, 28223, Spain
| | | | - Frank Sargent
- School of Natural & Environmental Sciences, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK.,School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| |
Collapse
|