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Harahap BM, Ahring BK. Acetate Production from Syngas Produced from Lignocellulosic Biomass Materials along with Gaseous Fermentation of the Syngas: A Review. Microorganisms 2023; 11:microorganisms11040995. [PMID: 37110418 PMCID: PMC10143712 DOI: 10.3390/microorganisms11040995] [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: 02/22/2023] [Revised: 04/05/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Biotransformation of lignocellulose-derived synthetic gas (syngas) into acetic acid is a promising way of creating biochemicals from lignocellulosic waste materials. Acetic acid has a growing market with applications within food, plastics and for upgrading into a wide range of biofuels and bio-products. In this paper, we will review the microbial conversion of syngas to acetic acid. This will include the presentation of acetate-producing bacterial strains and their optimal fermentation conditions, such as pH, temperature, media composition, and syngas composition, to enhance acetate production. The influence of syngas impurities generated from lignocellulose gasification will further be covered along with the means to alleviate impurity problems through gas purification. The problem with mass transfer limitation of gaseous fermentation will further be discussed as well as ways to improve gas uptake during the fermentation.
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Affiliation(s)
- Budi Mandra Harahap
- Bioproducts, Science, and Engineering Laboratory, Washington State University Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA
- Department of Biological System Engineering, Washington State University, L. J. Smith Hall, Pullman, WA 99164, USA
| | - Birgitte K Ahring
- Bioproducts, Science, and Engineering Laboratory, Washington State University Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA
- Department of Biological System Engineering, Washington State University, L. J. Smith Hall, Pullman, WA 99164, USA
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Wegner Hall, Pullman, WA 99164, USA
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2
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Meier AB, Oppermann S, Drake HL, Schmidt O. The root zone of graminoids: A niche for H2-consuming acetogens in a minerotrophic peatland. Front Microbiol 2022; 13:978296. [PMID: 35992704 PMCID: PMC9391049 DOI: 10.3389/fmicb.2022.978296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
The importance of acetogens for H2 turnover and overall anaerobic degradation in peatlands remains elusive. In the well-studied minerotrophic peatland fen Schlöppnerbrunnen, H2-consuming acetogens are conceptualized to be largely outcompeted by iron reducers, sulfate reducers, and hydrogenotrophic methanogens in bulk peat soil. However, in root zones of graminoids, fermenters thriving on rhizodeposits and root litter might temporarily provide sufficient H2 for acetogens. In the present study, root-free peat soils from around the roots of Molinia caerulea and Carex rostrata (i.e., two graminoids common in fen Schlöpnnerbrunnen) were anoxically incubated with or without supplemental H2 to simulate conditions of high and low H2 availability in the fen. In unsupplemented soil treatments, H2 concentrations were largely below the detection limit (∼10 ppmV) and possibly too low for acetogens and methanogens, an assumption supported by the finding that neither acetate nor methane substantially accumulated. In the presence of supplemental H2, acetate accumulation exceeded CH4 accumulation in Molinia soil whereas acetate and methane accumulated equally in Carex soil. However, reductant recoveries indicated that initially, additional unknown processes were involved either in H2 consumption or the consumption of acetate produced by H2-consuming acetogens. 16S rRNA and 16S rRNA gene analyses revealed that potential acetogens (Clostridium, Holophagaceae), methanogens (Methanocellales, Methanobacterium), iron reducers (Geobacter), and physiologically uncharacterized phylotypes (Acidobacteria, Actinobacteria, Bacteroidetes) were stimulated by supplemental H2 in soil treatments. Phylotypes closely related to clostridial acetogens were also active in soil-free Molinia and Carex root treatments with or without supplemental H2. Due to pronounced fermentation activities, H2 consumption was less obvious in root treatments, and acetogens likely thrived on root organic carbon and fermentation products (e.g., ethanol) in addition to H2. Collectively, the data highlighted that in fen Schlöppnerbrunnen, acetogens are associated to graminoid roots and inhabit the peat soil around the roots, where they have to compete for H2 with methanogens and iron reducers. Furthermore, the study underscored that the metabolically flexible acetogens do not rely on H2, potentially a key advantage over other H2 consumers under the highly dynamic conditions characteristic for the root-zones of graminoids in peatlands.
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Affiliation(s)
- Anja B. Meier
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Sindy Oppermann
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Harold L. Drake
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
| | - Oliver Schmidt
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
- *Correspondence: Oliver Schmidt,
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3
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Li Y, Liu B, Chen J, Yue X. Carbon-Nitrogen-Sulfur-Related Microbial Taxa and Genes Maintained the Stability of Microbial Communities in Coals. ACS OMEGA 2022; 7:22671-22681. [PMID: 35811862 PMCID: PMC9260939 DOI: 10.1021/acsomega.2c02126] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/08/2022] [Indexed: 06/03/2023]
Abstract
Coal microbes are the predominant form of life in the subsurface ecosystem, which play a vital role in biogeochemical cycles. However, the systematic information about carbon-nitrogen-sulfur (C-N-S)-related microbial communities in coal seams is limited. In this study, 16S rRNA gene data from a total of 93 microbial communities in coals were collected for meta-analysis. The results showed that 718 functional genera were related to the C-N-S cycle, wherein N2 fixation, denitrification, and C degradation groups dominated in relative abundance, Chao1 richness, Shannon diversity, and niche width. Genus Pseudomonas having the most C-N-S-related functions showed the highest relative abundance, and genus Herbaspirillum with a higher abundance participated in C degradation, CH4 oxidation, N2 fixation, ammoxidation, and denitrification. Such Herbaspirillum was a core genus in the co-occurrence network of microbial prokaryotes and showed higher levels in weight degree, betweenness centrality, and eigenvector centrality. In addition, most of the methanogens could fix N2 and dominated in the N2 fixation groups. Among them, genera Methanoculleus and Methanosaeta showed higher levels in the betweenness centrality index. In addition, the genus Clostridium was linked to the methanogenesis co-occurrence network module. In parallel, the S reduction gene was present in the highest total relative abundance of genes, followed by the C degradation and the denitrification genes, and S genes (especially cys genes) were the main genes linked to the co-occurrence network of the C-N-S-related genes. In summary, this study strengthened our knowledge regarding the C-N-S-related coal microbial communities, which is of great significance in understanding the microbial ecology and geochemical cycle of coals.
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Affiliation(s)
- Yang Li
- State
Key Laboratory of Mining Response and Disaster Prevention and Control
in Deep Coal Mines, Anhui University of
Science & Technology, Huainan, Anhui 232001, China
- Institute
of Energy, Hefei Comprehensive National Science Center, Hefei, Anhui 230031, China
| | - Bingjun Liu
- State
Key Laboratory of Mining Response and Disaster Prevention and Control
in Deep Coal Mines, Anhui University of
Science & Technology, Huainan, Anhui 232001, China
- Institute
of Energy, Hefei Comprehensive National Science Center, Hefei, Anhui 230031, China
| | - Jian Chen
- Coal
Mining National Engineering and Technology Research Institute, Huainan, Anhui 232001, China
| | - Xuelian Yue
- Jinneng
Holding Shanxi Science and Technology Research Institute Co. LTD., Taiyuan, Shanxi 030600, China
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4
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Lee H, Bae J, Jin S, Kang S, Cho BK. Engineering Acetogenic Bacteria for Efficient One-Carbon Utilization. Front Microbiol 2022; 13:865168. [PMID: 35615514 PMCID: PMC9124964 DOI: 10.3389/fmicb.2022.865168] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/19/2022] [Indexed: 12/03/2022] Open
Abstract
C1 gases, including carbon dioxide (CO2) and carbon monoxide (CO), are major contributors to climate crisis. Numerous studies have been conducted to fix and recycle C1 gases in order to solve this problem. Among them, the use of microorganisms as biocatalysts to convert C1 gases to value-added chemicals is a promising solution. Acetogenic bacteria (acetogens) have received attention as high-potential biocatalysts owing to their conserved Wood–Ljungdahl (WL) pathway, which fixes not only CO2 but also CO. Although some metabolites have been produced via C1 gas fermentation on an industrial scale, the conversion of C1 gases to produce various biochemicals by engineering acetogens has been limited. The energy limitation of acetogens is one of the challenges to overcome, as their metabolism operates at a thermodynamic limit, and the low solubility of gaseous substrates results in a limited supply of cellular energy. This review provides strategies for developing efficient platform strains for C1 gas conversion, focusing on engineering the WL pathway. Supplying liquid C1 substrates, which can be obtained from CO2, or electricity is introduced as a strategy to overcome the energy limitation. Future prospective approaches on engineering acetogens based on systems and synthetic biology approaches are also discussed.
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Affiliation(s)
- Hyeonsik Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jiyun Bae
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Sangrak Jin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seulgi Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- *Correspondence: Byung-Kwan Cho,
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5
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Biological conversion of carbon monoxide and hydrogen by anaerobic culture: Prospect of anaerobic digestion and thermochemical processes combination. Biotechnol Adv 2021; 58:107886. [PMID: 34915147 DOI: 10.1016/j.biotechadv.2021.107886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/26/2021] [Accepted: 12/08/2021] [Indexed: 01/04/2023]
Abstract
Waste biomass is considered a promising renewable energy feedstock that can be converted by anaerobic digestion. However, anaerobic digestion application can be challenging due to the structural complexity of several waste biomass kinds. Therefore, coupling anaerobic digestion with thermochemical processes can offset the limitations and convert the hardly biodegradable waste biomass, including digestate residue, into value-added products: syngas and pyrogas (gaseous mixtures consisting mainly of H2, CO, CO2), bio-oil, and biochar for further valorisation. In this review, the utilisation boundaries and benefits of the aforementioned products by anaerobic culture are discussed. First, thermochemical process parameters for an enhanced yield of desired products are summarised. Particularly, the microbiology of CO and H2 mixture biomethanation and fermentation in anaerobic digestion is presented. Finally, the state-of-the-art biological conversion of syngas and pyrogas to CH4 mediated by anaerobic culture is adequately described. Extensive research shows the successful selective biological conversion of CO and H2 to CH4, acetic acid, and alcohols. The main bottleneck is the gas-liquid mass transfer which can be enhanced appropriately by bioreactors' configurations. A few research groups focus on bio-oil and biochar addition into anaerobic digesters. However, according to the literature review, there has been no research for utilising all value-added products at once in anaerobic digestion published so far. Although synergic effects of such can be expected. In summary, the combination of anaerobic digestion and thermochemical processes is a promising alternative for wide-scale waste biomass utilisation in practice.
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6
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Meier AB, Oppermann S, Drake HL, Schmidt O. Organic carbon from graminoid roots as a driver of fermentation in a fen. FEMS Microbiol Ecol 2021; 97:6412523. [PMID: 34718537 DOI: 10.1093/femsec/fiab143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Fen Schlöppnerbrunnen is a moderately acidic methane-emitting peatland overgrown by Molinia caerulea and other wetland graminoids (e.g. Carex rostrata). Recently, the accumulation of H2, an indicator for fermentation, was observed with anoxically incubated C. rostrata roots but not with root-free fen soil. Based on this finding, we hypothesized that root-derived organic carbon has a higher capacity to promote fermentation processes than peat organic carbon from root-free fen soil. To address this hypothesis, C. rostrata and M. caerulea roots were anoxically incubated with or without fen soil and the product profiles of root treatments were compared with those of root-free soil treatments. Ethanol, acetate, propionate, butyrate, H2 and CO2 accumulated in root treatments and collective amounts of carbon in accumulating products were 20-200 times higher than those in root-free soil treatments, in which mainly CO2 accumulated. Analyses of 16S rRNA and 16S rRNA gene sequences revealed that Clostridium, Propionispira and Rahnella, representatives of butyrate, propionate and mixed acid fermenters, respectively, were relatively enriched in root treatments. In contrast, differences of the microbial community before and after incubation were marginal in root-free soil treatments. Collectively, these findings supported the assumed stimulatory effect of root-derived organic carbon on fen fermenters.
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Affiliation(s)
- Anja B Meier
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
| | - Sindy Oppermann
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
| | - Harold L Drake
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
| | - Oliver Schmidt
- Department of Ecological Microbiology, University of Bayreuth, Bayreuth 95440, Germany
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7
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Arrieta-Ortiz ML, Immanuel SRC, Turkarslan S, Wu WJ, Girinathan BP, Worley JN, DiBenedetto N, Soutourina O, Peltier J, Dupuy B, Bry L, Baliga NS. Predictive regulatory and metabolic network models for systems analysis of Clostridioides difficile. Cell Host Microbe 2021; 29:1709-1723.e5. [PMID: 34637780 PMCID: PMC8595754 DOI: 10.1016/j.chom.2021.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/29/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022]
Abstract
We present predictive models for comprehensive systems analysis of Clostridioides difficile, the etiology of pseudomembranous colitis. By leveraging 151 published transcriptomes, we generated an EGRIN model that organizes 90% of C. difficile genes into a transcriptional regulatory network of 297 co-regulated modules, implicating genes in sporulation, carbohydrate transport, and metabolism. By advancing a metabolic model through addition and curation of metabolic reactions including nutrient uptake, we discovered 14 amino acids, diverse carbohydrates, and 10 metabolic genes as essential for C. difficile growth in the intestinal environment. Finally, we developed a PRIME model to uncover how EGRIN-inferred combinatorial gene regulation by transcription factors, such as CcpA and CodY, modulates essential metabolic processes to enable C. difficile growth relative to commensal colonization. The C. difficile interactive web portal provides access to these model resources to support collaborative systems-level studies of context-specific virulence mechanisms in C. difficile.
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Affiliation(s)
| | | | | | - Wei-Ju Wu
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Brintha P Girinathan
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jay N Worley
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nicholas DiBenedetto
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-yvette 91198, France
| | - Johann Peltier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-yvette 91198, France
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries anaérobies, Institut Pasteur, Université de Paris, UMR CNRS 2001, Paris 75015, France
| | - Lynn Bry
- Massachusetts Host-Microbiome Center, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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8
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Wang Q, Al Makishah NH, Li Q, Li Y, Liu W, Sun X, Wen Z, Yang S. Developing Clostridia as Cell Factories for Short- and Medium-Chain Ester Production. Front Bioeng Biotechnol 2021; 9:661694. [PMID: 34164382 PMCID: PMC8215697 DOI: 10.3389/fbioe.2021.661694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/19/2021] [Indexed: 11/21/2022] Open
Abstract
Short- and medium-chain volatile esters with flavors and fruity fragrances, such as ethyl acetate, butyl acetate, and butyl butyrate, are usually value-added in brewing, food, and pharmacy. The esters can be naturally produced by some microorganisms. As ester-forming reactions are increasingly deeply understood, it is possible to produce esters in non-natural but more potential hosts. Clostridia are a group of important industrial microorganisms since they can produce a variety of volatile organic acids and alcohols with high titers, especially butanol and butyric acid through the CoA-dependent carbon chain elongation pathway. This implies sufficient supplies of acyl-CoA, organic acids, and alcohols in cells, which are precursors for ester production. Besides, some Clostridia could utilize lignocellulosic biomass, industrial off-gas, or crude glycerol to produce other branched or straight-chain alcohols and acids. Therefore, Clostridia offer great potential to be engineered to produce short- and medium-chain volatile esters. In the review, the efforts to produce esters from Clostridia via in vitro lipase-mediated catalysis and in vivo alcohol acyltransferase (AAT)-mediated reaction are comprehensively revisited. Besides, the advantageous characteristics of several Clostridia and clostridial consortia for bio-ester production and the driving force of synthetic biology to clostridial chassis development are also discussed. It is believed that synthetic biotechnology should enable the future development of more effective Clostridia for ester production.
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Affiliation(s)
- Qingzhuo Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Naief H Al Makishah
- Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Qi Li
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Yanan Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Wenzheng Liu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Xiaoman Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zhiqiang Wen
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Sheng Yang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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9
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Syngas Derived from Lignocellulosic Biomass Gasification as an Alternative Resource for Innovative Bioprocesses. Processes (Basel) 2020. [DOI: 10.3390/pr8121567] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H2, CO, and CO2. The major challenge of biomass gasification is the syngas’s final quality. Consequently, the development of effective syngas clean-up technologies has gained increased interest in recent years. Furthermore, the bioconversion of syngas components has been intensively studied using acetogenic bacteria and their Wood–Ljungdahl pathway to produce, among others, acetate, ethanol, butyrate, butanol, caproate, hexanol, 2,3-butanediol, and lactate. Nowadays, syngas fermentation appears to be a promising alternative for producing commodity chemicals in comparison to fossil-based processes. Research studies on syngas fermentation have been focused on process design and optimization, investigating the medium composition, operating parameters, and bioreactor design. Moreover, metabolic engineering efforts have been made to develop genetically modified strains with improved production. In 2018, for the first time, a syngas fermentation pilot plant from biomass gasification was built by LanzaTech Inc. in cooperation with Aemetis, Inc. Future research will focus on coupling syngas fermentation with additional bioprocesses and/or on identifying new non-acetogenic microorganisms to produce high-value chemicals beyond acetate and ethanol.
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10
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Takors R, Kopf M, Mampel J, Bluemke W, Blombach B, Eikmanns B, Bengelsdorf FR, Weuster-Botz D, Dürre P. Using gas mixtures of CO, CO 2 and H 2 as microbial substrates: the do's and don'ts of successful technology transfer from laboratory to production scale. Microb Biotechnol 2018; 11:606-625. [PMID: 29761637 PMCID: PMC6011938 DOI: 10.1111/1751-7915.13270] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/26/2018] [Accepted: 03/28/2018] [Indexed: 01/26/2023] Open
Abstract
The reduction of CO2 emissions is a global effort which is not only supported by the society and politicians but also by the industry. Chemical producers worldwide follow the strategic goal to reduce CO2 emissions by replacing existing fossil-based production routes with sustainable alternatives. The smart use of CO and CO2 /H2 mixtures even allows to produce important chemical building blocks consuming the said gases as substrates in carboxydotrophic fermentations with acetogenic bacteria. However, existing industrial infrastructure and market demands impose constraints on microbes, bioprocesses and products that require careful consideration to ensure technical and economic success. The mini review provides scientific and industrial facets finally to enable the successful implementation of gas fermentation technologies in the industrial scale.
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Affiliation(s)
- Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, 70569, Stuttgart, Germany
| | - Michael Kopf
- BASF SE, Bio-Process Development, Carl-Bosch-Str. 38, 67056, Ludwigshafen, Germany
| | - Joerg Mampel
- BRAIN AG, Darmstädter Straße 34-36, 64673, Zwingenberg, Germany
| | - Wilfried Bluemke
- Evonik Technology and Infrastructure GmbH, Process Technology & Engineering, Rodenbacher Chaussee 4, 63457, Hanau-Wolfgang, Germany
| | - Bastian Blombach
- Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, 70569, Stuttgart, Germany
| | - Bernhard Eikmanns
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Frank R Bengelsdorf
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Dirk Weuster-Botz
- Department of Mechanical Engineering, Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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11
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Bengelsdorf FR, Beck MH, Erz C, Hoffmeister S, Karl MM, Riegler P, Wirth S, Poehlein A, Weuster-Botz D, Dürre P. Bacterial Anaerobic Synthesis Gas (Syngas) and CO 2+H 2 Fermentation. ADVANCES IN APPLIED MICROBIOLOGY 2018; 103:143-221. [PMID: 29914657 DOI: 10.1016/bs.aambs.2018.01.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Anaerobic bacterial gas fermentation gains broad interest in various scientific, social, and industrial fields. This microbial process is carried out by a specific group of bacterial strains called acetogens. All these strains employ the Wood-Ljungdahl pathway but they belong to different taxonomic groups. Here we provide an overview of the metabolism of acetogens and naturally occurring products. Characteristics of 61 strains were summarized and selected acetogens described in detail. Acetobacterium woodii, Clostridium ljungdahlii, and Moorella thermoacetica serve as model organisms. Results of approaches such as genome-scale modeling, proteomics, and transcriptomics are discussed. Metabolic engineering of acetogens can be used to expand the product portfolio to platform chemicals and to study different aspects of cell physiology. Moreover, the fermentation of gases requires specific reactor configurations and the development of the respective technology, which can be used for an industrial application. Even though the overall process will have a positive effect on climate, since waste and greenhouse gases could be converted into commodity chemicals, some legislative barriers exist, which hamper successful exploitation of this technology.
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Affiliation(s)
- Frank R Bengelsdorf
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany.
| | - Matthias H Beck
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Catarina Erz
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Sabrina Hoffmeister
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Michael M Karl
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Peter Riegler
- Technical University of Munich, Institute of Biochemical Engineering, Garching, Germany
| | - Steffen Wirth
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University, Göttingen, Germany
| | - Dirk Weuster-Botz
- Technical University of Munich, Institute of Biochemical Engineering, Garching, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
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12
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Production of chemicals from C1 gases (CO, CO2) by Clostridium carboxidivorans. World J Microbiol Biotechnol 2017; 33:43. [DOI: 10.1007/s11274-016-2188-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/07/2016] [Indexed: 12/21/2022]
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13
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Liew F, Henstra AM, Kӧpke M, Winzer K, Simpson SD, Minton NP. Metabolic engineering of Clostridium autoethanogenum for selective alcohol production. Metab Eng 2017; 40:104-114. [PMID: 28111249 PMCID: PMC5367853 DOI: 10.1016/j.ymben.2017.01.007] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 11/01/2016] [Accepted: 01/19/2017] [Indexed: 01/27/2023]
Abstract
Gas fermentation using acetogenic bacteria such as Clostridium autoethanogenum offers an attractive route for production of fuel ethanol from industrial waste gases. Acetate reduction to acetaldehyde and further to ethanol via an aldehyde: ferredoxin oxidoreductase (AOR) and alcohol dehydrogenase has been postulated alongside the classic pathway of ethanol formation via a bi-functional aldehyde/alcohol dehydrogenase (AdhE). Here we demonstrate that AOR is critical to ethanol formation in acetogens and inactivation of AdhE led to consistently enhanced autotrophic ethanol production (up to 180%). Using ClosTron and allelic exchange mutagenesis, which was demonstrated for the first time in an acetogen, we generated single mutants as well as double mutants for both aor and adhE isoforms to confirm the role of each gene. The aor1+2 double knockout strain lost the ability to convert exogenous acetate, propionate and butyrate into the corresponding alcohols, further highlighting the role of these enzymes in catalyzing the thermodynamically unfavourable reduction of carboxylic acids into alcohols. 180% improvement in C. autoethanogenum ethanol production via metabolic engineering. Confirmed role of AOR in autotrophic ethanol production of acetogens. Generated both aor and adhE mutants of C. autoethanogenum.. Demonstrated allelic exchange mutagenesis for stable deletions in acetogens. Inactivation of adhE and aor2, but not aor1, improves autotrophic ethanol production.
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Affiliation(s)
- Fungmin Liew
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham NG7 2RD, UK; LanzaTech Inc., 8045 Lamon Avenue, Suite 400, Skokie, IL, USA
| | - Anne M Henstra
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham NG7 2RD, UK
| | - Michael Kӧpke
- LanzaTech Inc., 8045 Lamon Avenue, Suite 400, Skokie, IL, USA
| | - Klaus Winzer
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham NG7 2RD, UK
| | - Sean D Simpson
- LanzaTech Inc., 8045 Lamon Avenue, Suite 400, Skokie, IL, USA
| | - Nigel P Minton
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham NG7 2RD, UK.
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Clostridia: a flexible microbial platform for the production of alcohols. Curr Opin Chem Biol 2016; 35:65-72. [PMID: 27619003 DOI: 10.1016/j.cbpa.2016.08.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 11/22/2022]
Abstract
Solventogenic clostridia are native producers of ethanol and many higher alcohols employing a broad range of cheap renewable substrates, such as lignocellulosic materials and C1 gases (CO and CO2). These characteristics enable solventogenic clostridia to act as flexible microbial platforms for the production of liquid biofuels. With the rapid development of genetic tools in recent years, the intrinsic intractability of clostridia has been largely overcome, thus, engineering clostridia for production of chemicals and fuels has attracted increasing interests. Here, we provide an overview of recent progress in the production of alcohols based on solventogenic clostridia. Saccharolytic, cellulolytic and gas-fermenting clostridia are discussed, with a special focus on strategies for metabolic engineering to enable and to improve clostridia for the production of higher alcohols.
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15
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Liew F, Martin ME, Tappel RC, Heijstra BD, Mihalcea C, Köpke M. Gas Fermentation-A Flexible Platform for Commercial Scale Production of Low-Carbon-Fuels and Chemicals from Waste and Renewable Feedstocks. Front Microbiol 2016; 7:694. [PMID: 27242719 PMCID: PMC4862988 DOI: 10.3389/fmicb.2016.00694] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/26/2016] [Indexed: 12/13/2022] Open
Abstract
There is an immediate need to drastically reduce the emissions associated with global fossil fuel consumption in order to limit climate change. However, carbon-based materials, chemicals, and transportation fuels are predominantly made from fossil sources and currently there is no alternative source available to adequately displace them. Gas-fermenting microorganisms that fix carbon dioxide (CO2) and carbon monoxide (CO) can break this dependence as they are capable of converting gaseous carbon to fuels and chemicals. As such, the technology can utilize a wide range of feedstocks including gasified organic matter of any sort (e.g., municipal solid waste, industrial waste, biomass, and agricultural waste residues) or industrial off-gases (e.g., from steel mills or processing plants). Gas fermentation has matured to the point that large-scale production of ethanol from gas has been demonstrated by two companies. This review gives an overview of the gas fermentation process, focusing specifically on anaerobic acetogens. Applications of synthetic biology and coupling gas fermentation to additional processes are discussed in detail. Both of these strategies, demonstrated at bench-scale, have abundant potential to rapidly expand the commercial product spectrum of gas fermentation and further improve efficiencies and yields.
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Groher A, Weuster-Botz D. Comparative reaction engineering analysis of different acetogenic bacteria for gas fermentation. J Biotechnol 2016; 228:82-94. [PMID: 27107467 DOI: 10.1016/j.jbiotec.2016.04.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/08/2016] [Accepted: 04/19/2016] [Indexed: 01/05/2023]
Abstract
The production of chemicals by syngas fermentation is a promising alternative to heterotrophic fermentation processes. The autotrophic process performances of the so far not well studied acetogens Acetobacterium fimetarium, Acetobacterium wieringae, Blautia hydrogenotrophica, Clostridium magnum, Eubacterium aggregans, Sporomusa acidovorans, Sporomusa ovata and Terrisporobacter mayombei were characterized. Acetobacterium woodii was used as reference strain. Standardized batch experiments with continuous supply of the gaseous substrates CO2 and H2 were performed in fully controlled stirred-tank bioreactors. A. wieringae and S. ovata showed by far the highest growth rates and maximum biomass concentrations among the acetogens under study. Aside from the reference strain A. woodii, highest volumetric (17.96gL(-1)d(-1)) as well as cell specific acetate formation rates (21.03gg(-1)d(-1)) were observed with S. ovata resulting in a final acetate concentration of 32.2gL(-1). Accumulation of formate with up to 4.8gL(-1) was observed with all acetogens. Ethanol was produced autotrophically with up to 0.42gL(-1) by four of the acetogenic bacteria under study (A. wieringae, C. magnum, S. acidovorans and S. ovata) and also by A. woodii. Butyrate was formed with up to 0.14gL(-1) by three of the acetogenic bacteria under study (C. magnum, B. hydrogenotrophica and E. aggregans). Due to its superior process performances S. ovata may be a promising host for redirecting carbon fluxes by applying metabolic engineering and tools of synthetic biology to produce non-natural chemicals from syngas.
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Affiliation(s)
- Anna Groher
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, D 85748 Garching, Germany
| | - Dirk Weuster-Botz
- Institute of Biochemical Engineering, Technische Universität München, Boltzmannstr. 15, D 85748 Garching, Germany.
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17
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Dürre P. Butanol formation from gaseous substrates. FEMS Microbiol Lett 2016; 363:fnw040. [PMID: 26903012 DOI: 10.1093/femsle/fnw040] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2016] [Indexed: 01/24/2023] Open
Abstract
Mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called ABE fermentation (for acetone-butanol-ethanol). However, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. In view of economic considerations, a biotechnological process based on cheap and abundant gases such as CO and CO2 as a carbon source is preferable to more expensive sugar or starch fermentation. In addition, any conflict for use of substrates that can also serve as human nutrition is avoided. Natural formation of butanol has been found with, e.g. Clostridium carboxidivorans, while metabolic engineering for butanol production was successful using, e.g. C. ljungdahlii. Production of butanol from CO2 under photoautotrophic conditions was also possible by recombinant DNA construction of a respective cyanobacterial Synechococcus sp. PCC 7942 strain.
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Affiliation(s)
- Peter Dürre
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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18
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Shen Y, Jarboe L, Brown R, Wen Z. A thermochemical–biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals. Biotechnol Adv 2015; 33:1799-813. [DOI: 10.1016/j.biotechadv.2015.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 12/28/2022]
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Ganigué R, Puig S, Batlle-Vilanova P, Balaguer MD, Colprim J. Microbial electrosynthesis of butyrate from carbon dioxide. Chem Commun (Camb) 2015; 51:3235-8. [DOI: 10.1039/c4cc10121a] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This work proves for the first time the bioelectrochemical production of butyrate from CO2as a sole carbon source.
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Affiliation(s)
- R. Ganigué
- LEQUIA
- Institute of the Environment
- University of Girona
- Campus de Montilivi
- Girona
| | - S. Puig
- LEQUIA
- Institute of the Environment
- University of Girona
- Campus de Montilivi
- Girona
| | - P. Batlle-Vilanova
- LEQUIA
- Institute of the Environment
- University of Girona
- Campus de Montilivi
- Girona
| | - M. D. Balaguer
- LEQUIA
- Institute of the Environment
- University of Girona
- Campus de Montilivi
- Girona
| | - J. Colprim
- LEQUIA
- Institute of the Environment
- University of Girona
- Campus de Montilivi
- Girona
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Draft Genome Sequence of Acid-Tolerant Clostridium drakei SL1T, a Potential Chemical Producer through Syngas Fermentation. GENOME ANNOUNCEMENTS 2014; 2:genomeA.00387-14. [PMID: 24831144 PMCID: PMC4022808 DOI: 10.1128/genomea.00387-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Clostridium drakei SL1T is a strictly anaerobic, H2-utilizing, and acid-tolerant acetogen isolated from an acidic sediment that is a potential platform for commodity chemical production from syngas fermentation. The draft genome sequence of this strain will enable determination of the acid resistance and autotrophic pathway of the acetogen.
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In situ hydrogen utilization for high fraction acetate production in mixed culture hollow-fiber membrane biofilm reactor. Appl Microbiol Biotechnol 2013; 97:10233-40. [PMID: 24196583 DOI: 10.1007/s00253-013-5281-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/17/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022]
Abstract
Syngas fermentation is a promising route for resource recovery. Acetate is an important industrial chemical product and also an attractive precursor for liquid biofuels production. This study demonstrated high fraction acetate production from syngas (H₂ and CO₂) in a hollow-fiber membrane biofilm reactor, in which the hydrogen utilizing efficiency reached 100% during the operational period. The maximum concentration of acetate in batch mode was 12.5 g/L, while the acetate concentration in continuous mode with a hydraulic retention time of 9 days was 3.6 ± 0.1 g/L. Since butyrate concentration was rather low and below 0.1 g/L, the acetate fraction was higher than 99% in both batch and continuous modes. Microbial community analysis showed that the biofilm was dominated by Clostridium spp., such as Clostridium ljungdahlii and Clostridium drakei, the percentage of which was 70.5%. This study demonstrates a potential technology for the in situ utilization of syngas and valuable chemical production.
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22
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Artz RRE. Microbial Community Structure and Carbon Substrate use in Northern Peatlands. CARBON CYCLING IN NORTHERN PEATLANDS 2013. [DOI: 10.1029/2008gm000806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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23
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Lin X, Green S, Tfaily MM, Prakash O, Konstantinidis KT, Corbett JE, Chanton JP, Cooper WT, Kostka JE. Microbial community structure and activity linked to contrasting biogeochemical gradients in bog and fen environments of the Glacial Lake Agassiz Peatland. Appl Environ Microbiol 2012; 78:7023-31. [PMID: 22843538 PMCID: PMC3457479 DOI: 10.1128/aem.01750-12] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/20/2012] [Indexed: 11/20/2022] Open
Abstract
The abundances, compositions, and activities of microbial communities were investigated at bog and fen sites in the Glacial Lake Agassiz Peatland of northwestern Minnesota. These sites contrast in the reactivity of dissolved organic matter (DOM) and the presence or absence of groundwater inputs. Microbial community composition was characterized using pyrosequencing and clone library construction of phylogenetic marker genes. Microbial distribution patterns were linked to pH, concentrations of dissolved organic carbon and nitrogen, C/N ratios, optical properties of DOM, and activities of laccase and peroxidase enzymes. Both bacterial and archaeal richness and rRNA gene abundance were >2 times higher on average in the fen than in the bog, in agreement with a higher pH, labile DOM content, and enhanced enzyme activities in the fen. Fungi were equivalent to an average of 1.4% of total prokaryotes in gene abundance assayed by quantitative PCR. Results revealed statistically distinct spatial patterns between bacterial and fungal communities. Fungal distribution did not covary with pH and DOM optical properties and was vertically stratified, with a prevalence of Ascomycota and Basidiomycota near the surface and much higher representation of Zygomycota in the subsurface. In contrast, bacterial community composition largely varied between environments, with the bog dominated by Acidobacteria (61% of total sequences), while the Firmicutes (52%) dominated in the fen. Acetoclastic Methanosarcinales showed a much higher relative abundance in the bog, in contrast to the dominance of diverse hydrogenotrophic methanogens in the fen. This is the first quantitative and compositional analysis of three microbial domains in peatlands and demonstrates that the microbial abundance, diversity, and activity parallel with the pronounced differences in environmental variables between bog and fen sites.
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Affiliation(s)
- X. Lin
- Georgia Institute of Technology, Schools of Biology and Earth & Atmospheric Sciences, Atlanta, Georgia, USA
| | - S. Green
- University of Illinois at Chicago, Chicago, Illinois, USA
| | - M. M. Tfaily
- Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, Florida, USA
| | - O. Prakash
- Georgia Institute of Technology, Schools of Biology and Earth & Atmospheric Sciences, Atlanta, Georgia, USA
| | - K. T. Konstantinidis
- Georgia Institute of Technology, School of Civil & Environmental Engineering, Atlanta, Georgia, USA
| | - J. E. Corbett
- Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, Florida, USA
| | - J. P. Chanton
- Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, Florida, USA
| | - W. T. Cooper
- Florida State University, Department of Chemistry & Biochemistry, Tallahassee, Florida, USA
| | - J. E. Kostka
- Georgia Institute of Technology, Schools of Biology and Earth & Atmospheric Sciences, Atlanta, Georgia, USA
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Ukpong MN, Atiyeh HK, De Lorme MJM, Liu K, Zhu X, Tanner RS, Wilkins MR, Stevenson BS. Physiological response of Clostridium carboxidivorans during conversion of synthesis gas to solvents in a gas-fed bioreactor. Biotechnol Bioeng 2012; 109:2720-8. [PMID: 22566280 DOI: 10.1002/bit.24549] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 04/25/2012] [Accepted: 04/26/2012] [Indexed: 11/11/2022]
Abstract
Clostridium carboxidivorans P7 is one of three microbial catalysts capable of fermenting synthesis gas (mainly CO, CO(2) , and H(2) ) to produce the liquid biofuels ethanol and butanol. Gasification of feedstocks to produce synthesis gas (syngas), followed by microbial conversion to solvents, greatly expands the diversity of suitable feedstocks that can be used for biofuel production beyond commonly used food and energy crops to include agricultural, industrial, and municipal waste streams. C. carboxidivorans P7 uses a variation of the classic Wood-Ljungdahl pathway, identified through genome sequence-enabled approaches but only limited direct metabolic analyses. As a result, little is known about gene expression and enzyme activities during solvent production. In this study, we measured cell growth, gene expression, enzyme activity, and product formation in autotrophic batch cultures continuously fed a synthetic syngas mixture. These cultures exhibited an initial phase of growth, followed by acidogenesis that resulted in a reduction in pH. After cessation of growth, solventogenesis occurred, pH increased and maximum concentrations of acetate (41 mM), butyrate (1.4 mM), ethanol (61 mM), and butanol (7.1 mM) were achieved. Enzyme activities were highest during the growth phase, but expression of carbon monoxide dehydrogenase (CODH), Fe-only hydrogenases and two tandem bi-functional acetaldehyde/alcohol dehydrogenases were highest during specific stages of solventogenesis. Several amino acid substitutions between the tandem acetaldehyde/alcohol dehydrogenases and the differential expression of their genes suggest that they may have different roles during solvent formation. The data presented here provide a link between the expression of key enzymes, their measured activities and solvent production by C. carboxidivorans P7. This research also identifies potential targets for metabolic engineering efforts designed to produce higher amounts of ethanol or butanol from syngas. .
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Affiliation(s)
- Michael N Ukpong
- Department of Botany and Microbiology, University of Oklahoma, 770 Van Vleet Oval, Norman, OK 73019, USA
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Enrichment of arsenic transforming and resistant heterotrophic bacteria from sediments of two salt lakes in Northern Chile. Extremophiles 2012; 16:523-38. [PMID: 22555750 DOI: 10.1007/s00792-012-0452-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 04/02/2012] [Indexed: 02/07/2023]
Abstract
Microbial populations are involved in the arsenic biogeochemical cycle in catalyzing arsenic transformations and playing indirect roles. To investigate which ecotypes among the diverse microbial communities could have a role in cycling arsenic in salt lakes in Northern Chile and to obtain clues to facilitate their isolation in pure culture, sediment samples from Salar de Ascotán and Salar de Atacama were cultured in diluted LB medium amended with NaCl and arsenic, at different incubation conditions. The samples and the cultures were analyzed by nucleic acid extraction, fingerprinting analysis, and sequencing. Microbial reduction of As was evidenced in all the enrichments carried out in anaerobiosis. The results revealed that the incubation factors were more important for determining the microbial community structure than arsenic species and concentrations. The predominant microorganisms in enrichments from both sediments belonged to the Firmicutes and Proteobacteria phyla, but most of the bacterial ecotypes were confined to only one system. The occurrence of an active arsenic biogeochemical cycle was suggested in the system with the highest arsenic content that included populations compatible with microorganisms able to transform arsenic for energy conservation, accumulate arsenic, produce H(2), H(2)S and acetic acid (potential sources of electrons for arsenic reduction) and tolerate high arsenic levels.
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26
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Pathway engineering and synthetic biology using acetogens. FEBS Lett 2012; 586:2191-8. [PMID: 22710156 DOI: 10.1016/j.febslet.2012.04.043] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/24/2012] [Accepted: 04/24/2012] [Indexed: 01/05/2023]
Abstract
Acetogenic anaerobic bacteria are defined as organisms employing the Wood-Ljungdahl pathway to synthesize acetyl-CoA from CO(2) or CO. Their autotrophic mode of metabolism offers the biotechnological chance to combine use of abundantly available substrates with reduction of greenhouse gases. Several companies have already established pilot and demonstration plants for converting waste gases into ethanol, an important biofuel and a natural product of many acetogens. Recombinant DNA approaches now opened the door to construct acetogens, synthesizing important industrial bulk chemicals and biofuels such as acetone and butanol. Thus, novel microbial production platforms are available that no longer compete with nutritional feedstocks.
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Lee HS, Vermaas WF, Rittmann BE. Biological hydrogen production: prospects and challenges. Trends Biotechnol 2010; 28:262-71. [DOI: 10.1016/j.tibtech.2010.01.007] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 01/11/2010] [Accepted: 01/28/2010] [Indexed: 10/19/2022]
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28
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Drake HL, Horn MA, Wüst PK. Intermediary ecosystem metabolism as a main driver of methanogenesis in acidic wetland soil. ENVIRONMENTAL MICROBIOLOGY REPORTS 2009; 1:307-318. [PMID: 23765883 DOI: 10.1111/j.1758-2229.2009.00050.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Methanogens have a very limited substrate range, and their in situ activities are thus linked to 'intermediary ecosystem metabolism', i.e. complex trophic interactions with other microorganisms catalysing essential intermediary processes that ultimately drive methanogenesis. However, information on intermediary ecosystem metabolism and associated biota is fragmented and often conceptualized rather than resolved. The main objective of this review is to evaluate the concept of intermediary ecosystem metabolism in context with recent work aimed at resolving the complex trophic interactions of a methane-emitting peatland.
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Affiliation(s)
- Harold L Drake
- Department of Ecological Microbiology, University of Bayreuth, 95440 Bayreuth, Germany
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Wüst PK, Horn MA, Drake HL. Trophic links between fermenters and methanogens in a moderately acidic fen soil. Environ Microbiol 2009; 11:1395-409. [PMID: 19222542 DOI: 10.1111/j.1462-2920.2009.01867.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Trophic links between fermentation and methanogenesis of soil derived from a methane-emitting, moderately acidic temperate fen (pH 4.5) were investigated. Initial CO(2):CH(4) production ratios in anoxic microcosms indicated that methanogenesis was concomitant to other terminal anaerobic processes. Methane production in anoxic microcosms at in situ pH was stimulated by supplemental H(2)-CO(2), formate or methanol; supplemental acetate did not stimulate methanogenesis. Supplemental H(2)-CO(2), formate or methanol also stimulated the formation of acetate, indicating that the fen harbours moderately acid-tolerant acetogens. Supplemental monosaccharides (glucose, N-acetylglucosamine and xylose) stimulated the production of CO(2), H(2), acetate and other fermentation products when methanogenesis was inhibited with 2-bromoethane sulfonate 20 mM. Glucose stimulated methanogenesis in the absence of BES. Upper soil depths yielded higher anaerobic activities and also higher numbers of cells. Detected archaeal 16S rRNA genes were indicative of H(2)-CO(2)- and formate-consuming methanogens (Methanomicrobiaceae), obligate acetoclastic methanogens (Methanosaetaceae) and crenarchaeotes (groups I.1a, I.1c and I.3). Molecular analyses of partial sequences of 16S rRNA genes revealed the presence of Acidobacteria, Nitrospirales, Clamydiales, Clostridiales, Alpha-, Gamma-, Deltaproteobacteria and Cyanobacteria. These collective results suggest that this moderately acidic fen harbours phylogenetically diverse, moderately acid tolerant fermenters (both facultative aerobes and obligate anaerobes) that are trophically linked to methanogenesis.
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Affiliation(s)
- Pia K Wüst
- Department of Ecological Microbiology, University of Bayreuth, 95445 Bayreuth, Germany
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