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Allaart MT, Korkontzelos C, Sousa DZ, Kleerebezem R. A novel experimental method to determine substrate uptake kinetics of gaseous substrates applied to the carbon monoxide-fermenting Clostridium autoethanogenum. Biotechnol Bioeng 2024; 121:1325-1335. [PMID: 38265153 DOI: 10.1002/bit.28652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/25/2024]
Abstract
Syngas fermentation has gained momentum over the last decades. The cost-efficient design of industrial-scale bioprocesses is highly dependent on quantitative microbial growth data. Kinetic and stoichiometric models for syngas-converting microbes exist, but accurate experimental validation of the derived parameters is lacking. Here, we describe a novel experimental approach for measuring substrate uptake kinetics of gas-fermenting microbes using the model microorganism Clostridium autoethanogenum. One-hour disturbances of a steady-state chemostat bioreactor with increased CO partial pressures (up to 1.2 bar) allowed for measurement of biomass-specific CO uptake- and CO2 production rates (q CO ${q}_{{CO}}$ ,q CO 2 ${q}_{{{CO}}_{2}}$ ) using off-gas analysis. At a pCO of 1.2 bar, aq CO ${q}_{{CO}}$ of -119 ± 1 mmol g-1 X h-1 was measured. This value is 1.8-3.5-fold higher than previously reported experimental and kinetic modeling results for syngas fermenters. Analysis of the catabolic flux distribution reveals a metabolic shift towards ethanol production at the expense of acetate at pCO ≥ $\ge $ 0.6 atm, likely to be mediated by acetate availability and cellular redox state. We characterized this metabolic shift as acetogenic overflow metabolism. These results provide key mechanistic understanding of the factors steering the product spectrum of CO fermentation in C. autoethanogenum and emphasize the importance of dedicated experimental validation of kinetic parameters.
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Affiliation(s)
| | | | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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2
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Chen G, Wang R, Sun M, Chen J, Iyobosa E, Zhao J. Carbon dioxide reduction to high-value chemicals in microbial electrosynthesis system: Biological conversion and regulation strategies. CHEMOSPHERE 2023; 344:140251. [PMID: 37769909 DOI: 10.1016/j.chemosphere.2023.140251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
Large emissions of atmospheric carbon dioxide (CO2) are causing climatic and environmental problems. It is crucial to capture and utilize the excess CO2 through diverse methods, among which the microbial electrosynthesis (MES) system has become an attractive and promising technology to mitigate greenhouse effects while reducing CO2 to high-value chemicals. However, the biological conversion and metabolic pathways through microbial catalysis have not been clearly elucidated. This review first introduces the main acetogenic bacteria for CO2 reduction and extracellular electron transfer mechanisms in MES. It then intensively analyzes the CO2 bioconversion pathways and carbon chain elongation processes in MES, together with energy supply and utilization. The factors affecting MES performance, including physical, chemical, and biological aspects, are summarized, and the strategies to promote and regulate bioconversion in MES are explored. Finally, challenges and perspectives concerning microbial electrochemical carbon sequestration are proposed, and suggestions for future research are also provided. This review provides theoretical foundation and technical support for further development and industrial application of MES for CO2 reduction.
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Affiliation(s)
- Gaoxiang Chen
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Rongchang Wang
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China.
| | - Maoxin Sun
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Jie Chen
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Eheneden Iyobosa
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Jianfu Zhao
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
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3
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Robles-Iglesias R, Veiga MC, Kennes C. Sequential bioconversion of C 1-gases (CO, CO 2, syngas) into lipids, through the carboxylic acid platform, with Clostridium aceticum and Rhodosporidium toruloides. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 347:119097. [PMID: 37776787 DOI: 10.1016/j.jenvman.2023.119097] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/02/2023] [Accepted: 08/30/2023] [Indexed: 10/02/2023]
Abstract
Syngas (CO, CO2, H2) was effectively bioconverted into lipids in a two-stage process. In the first stage, C1-gases were bioconverted into acetic acid by the acetogenic species Clostridium aceticum through the Wood-Ljungdahl metabolic pathway in a stirred tank bioreactor, reaching a maximum acetic acid concentration of 11.5 g/L, with a production rate of 0.05 g/L·h. Throughout this experiment, samples were extracted at different periods, i.e., different concentrations, to be used in the second stage, aiming at the production of lipids from acetic acid. The yeast Rhodosporidium toruloides, inoculated in the acetogenic medium, was able to efficiently accumulate lipids from acetic acid generated in the first stage. The best results, in terms of lipid content, dry biomass, biomass yield (Y(X/S)) and lipid yield (Y(L/S)) were 39.5% g/g dry cell weight, 3 g/L, 0.35 and 0.107, respectively. In terms of abundance, the lipid profile followed the order: C18:1 > C16:0 > C18:2 > C18:0 > Others. Experiments were also performed to determine the toxicity exerted by high concentrations of acetic acid on R. toruloides, resulting in inhibition at initial acid concentrations around 18 g/L leading to a higher lag phase and being lethal to the yeast at initial acetic acid concentrations around 22 g/L and above. This research paves the way for a novel method of growing oleaginous yeasts to produce sustainable biofuels from syngas or C1-pollutant gases.
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Affiliation(s)
- Raúl Robles-Iglesias
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña, E-15008-La, Coruña, Spain
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña, E-15008-La, Coruña, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology - Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN group, University of La Coruña, E-15008-La, Coruña, Spain.
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4
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Zhang H, Zhang C, Nie X, Wu Y, Yang C, Jiang W, Gu Y. Pleiotropic Regulator GssR Positively Regulates Autotrophic Growth of Gas-Fermenting Clostridium ljungdahlii. Microorganisms 2023; 11:1968. [PMID: 37630531 PMCID: PMC10458427 DOI: 10.3390/microorganisms11081968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/29/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023] Open
Abstract
Clostridium ljungdahlii is a representative autotrophic acetogen capable of producing multiple chemicals from one-carbon gases (CO2/CO). The metabolic and regulatory networks of this carbon-fixing bacterium are interesting, but still remain minimally explored. Here, based on bioinformatics analysis followed by functional screening, we identified a RpiR family transcription factor (TF) that can regulate the autotrophic growth and carbon fixation of C. ljungdahlii. After deletion of the corresponding gene, the resulting mutant strain exhibited significantly impaired growth in gas fermentation, thus reducing the production of acetic acid and ethanol. In contrast, the overexpression of this TF gene could promote cell growth, indicating a positive regulatory effect of this TF in C. ljungdahlii. Thus, we named the TF as GssR (growth and solvent synthesis regulator). Through the following comparative transcriptomic analysis and biochemical verification, we discovered three important genes (encoding pyruvate carboxylase, carbon hunger protein CstA, and a BlaI family transcription factor) that were directly regulated by GssR. Furthermore, an upstream regulator, BirA, that could directly bind to gssR was found; thus, these two regulators may form a cascade regulation and jointly affect the physiology and metabolism of C. ljungdahlii. These findings substantively expand our understanding on the metabolic regulation of carbon fixation in gas-fermenting Clostridium species.
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Affiliation(s)
- Huan Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Can Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqun Nie
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuwei Wu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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Bäumler M, Burgmaier V, Herrmann F, Mentges J, Schneider M, Ehrenreich A, Liebl W, Weuster-Botz D. Continuous Production of Ethanol, 1-Butanol and 1-Hexanol from CO with a Synthetic Co-Culture of Clostridia Applying a Cascade of Stirred-Tank Bioreactors. Microorganisms 2023; 11:microorganisms11041003. [PMID: 37110426 PMCID: PMC10144111 DOI: 10.3390/microorganisms11041003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/06/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
Syngas fermentation with clostridial co-cultures is promising for the conversion of CO to alcohols. A CO sensitivity study with Clostridium kluyveri monocultures in batch operated stirred-tank bioreactors revealed total growth inhibition of C. kluyveri already at 100 mbar CO, but stable biomass concentrations and ongoing chain elongation at 800 mbar CO. On/off-gassing with CO indicated a reversible inhibition of C. kluyveri. A continuous supply of sulfide led to increased autotrophic growth and ethanol formation by Clostridium carboxidivorans even at unfavorable low CO concentrations. Based on these results, a continuously operated cascade of two stirred-tank reactors was established with a synthetic co-culture of both Clostridia. An amount of 100 mbar CO and additional sulfide supply enabled growth and chain elongation in the first bioreactor, whereas 800 mbar CO resulted in an efficient reduction of organic acids and de-novo synthesis of C2-C6 alcohols in the second reactor. High alcohol/acid ratios of 4.5-9.1 (w/w) were achieved in the steady state of the cascade process, and the space-time yields of the alcohols produced were improved by factors of 1.9-5.3 compared to a batch process. Further improvement of continuous production of medium chain alcohols from CO may be possible by applying less CO-sensitive chain-elongating bacteria in co-cultures.
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Affiliation(s)
- Miriam Bäumler
- Chair of Biochemical Engineering, Department of Energy and Process Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Veronika Burgmaier
- Chair of Biochemical Engineering, Department of Energy and Process Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Fabian Herrmann
- Chair of Biochemical Engineering, Department of Energy and Process Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Julian Mentges
- Chair of Biochemical Engineering, Department of Energy and Process Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Martina Schneider
- Chair of Microbiology, TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Armin Ehrenreich
- Chair of Microbiology, TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Dirk Weuster-Botz
- Chair of Biochemical Engineering, Department of Energy and Process Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
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6
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Allaart MT, Diender M, Sousa DZ, Kleerebezem R. Overflow metabolism at the thermodynamic limit of life: How carboxydotrophic acetogens mitigate carbon monoxide toxicity. Microb Biotechnol 2023; 16:697-705. [PMID: 36632026 PMCID: PMC10034630 DOI: 10.1111/1751-7915.14212] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/29/2022] [Accepted: 01/01/2023] [Indexed: 01/13/2023] Open
Abstract
Carboxydotrophic metabolism is gaining interest due to its applications in gas fermentation technology, enabling the conversion of carbon monoxide to fuels and commodities. Acetogenic carboxydotrophs play a central role in current gas fermentation processes. In contrast to other energy-rich microbial substrates, CO is highly toxic, which makes it a challenging substrate to utilize. Instantaneous scavenging of CO upon entering the cell is required to mitigate its toxicity. Experiments conducted with Clostridium autoethanogenum at different biomass-specific growth rates show that elevated ethanol production occurs at increasing growth rates. The increased allocation of electrons towards ethanol at higher growth rates strongly suggests that C. autoethanogenum employs a form of overflow metabolism to cope with high dissolved CO concentrations. We argue that this overflow branch enables acetogens to efficiently use CO at highly variable substrate influxes by increasing the conversion rate almost instantaneously when required to remove toxic substrate and promote growth. In this perspective, we will address the case study of C. autoethanogenum grown solely on CO and syngas mixtures to assess how it employs acetate reduction to ethanol as a form of overflow metabolism.
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Affiliation(s)
| | - Martijn Diender
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Robbert Kleerebezem
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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7
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Moreira JPC, Heap JT, Alves JI, Domingues L. Developing a genetic engineering method for Acetobacterium wieringae to expand one-carbon valorization pathways. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:24. [PMID: 36788587 PMCID: PMC9930230 DOI: 10.1186/s13068-023-02259-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 01/05/2023] [Indexed: 02/16/2023]
Abstract
BACKGROUND Developing new bioprocesses to produce chemicals and fuels with reduced production costs will greatly facilitate the replacement of fossil-based raw materials. In most fermentation bioprocesses, the feedstock usually represents the highest cost, which becomes the target for cost reduction. Additionally, the biorefinery concept advocates revenue growth from the production of several compounds using the same feedstock. Taken together, the production of bio commodities from low-cost gas streams containing CO, CO2, and H2, obtained from the gasification of any carbon-containing waste streams or off-gases from heavy industry (steel mills, processing plants, or refineries), embodies an opportunity for affordable and renewable chemical production. To achieve this, by studying non-model autotrophic acetogens, current limitations concerning low growth rates, toxicity by gas streams, and low productivity may be overcome. The Acetobacterium wieringae strain JM is a novel autotrophic acetogen that is capable of producing acetate and ethanol. It exhibits faster growth rates on various gaseous compounds, including carbon monoxide, compared to other Acetobacterium species, making it potentially useful for industrial applications. The species A. wieringae has not been genetically modified, therefore developing a genetic engineering method is important for expanding its product portfolio from gas fermentation and overall improving the characteristics of this acetogen for industrial demands. RESULTS This work reports the development and optimization of an electrotransformation protocol for A. wieringae strain JM, which can also be used in A. wieringae DSM 1911, and A. woodii DSM 1030. We also show the functionality of the thiamphenicol resistance marker, catP, and the functionality of the origins of replication pBP1, pCB102, pCD6, and pIM13 in all tested Acetobacterium strains, with transformation efficiencies of up to 2.0 × 103 CFU/μgDNA. Key factors affecting electrotransformation efficiency include OD600 of cell harvesting, pH of resuspension buffer, the field strength of the electric pulse, and plasmid amount. Using this method, the acetone production operon from Clostridium acetobutylicum was efficiently introduced in all tested Acetobacterium spp., leading to non-native biochemical acetone production via plasmid-based expression. CONCLUSIONS A. wieringae can be electrotransformed at high efficiency using different plasmids with different replication origins. The electrotransformation procedure and tools reported here unlock the genetic and metabolic manipulation of the biotechnologically relevant A. wieringae strains. For the first time, non-native acetone production is shown in A. wieringae.
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Affiliation(s)
- João P. C. Moreira
- grid.10328.380000 0001 2159 175XCEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal ,LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - John T. Heap
- grid.4563.40000 0004 1936 8868School of Life Sciences, University of Nottingham, Biodiscovery Institute, University Park, Nottingham, NG7 2RD UK
| | - Joana I. Alves
- grid.10328.380000 0001 2159 175XCEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal ,LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal. .,LABBELS - Associate Laboratory, Braga/Guimarães, Portugal.
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8
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Schulz S, Molitor B, Angenent LT. Acetate augmentation boosts the ethanol production rate and specificity by Clostridium ljungdahlii during gas fermentation with pure carbon monoxide. BIORESOURCE TECHNOLOGY 2023; 369:128387. [PMID: 36435417 DOI: 10.1016/j.biortech.2022.128387] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 06/16/2023]
Abstract
Recycling waste gases from industry is vital for the transition toward a circular economy. The model microbe Clostridium ljungdahlii reduces carbon from syngas and primarily produces acetate and ethanol. Here, a gas fermentation experiment is presented in chemostats with C. ljungdahlii and pure carbon monoxide (CO) as feedstock while entirely omitting yeast extract. A maximum ethanol production rate of 0.07 ± 0.01 g L-1 h-1 and a maximum average ethanol/acetate ratio of 1.41 ± 0.39 was observed under steady-state conditions. This confirmed that CO as the sole feedstock pushes the metabolism toward more reduced fermentation products. This effect was even more pronounced when 15 mM sodium acetate was added to the feed medium. An ethanol production rate of 0.23 ± 0.01 g L-1 h-1 was achieved, representing an increase of more than 240%. This increase was accompanied by an increase in cell density and selectivity toward ethanol, with a maximum average ethanol/acetate ratio of 92.96 ± 28.39. Oxygen contaminations voided this effect, although the cultures were still able to maintain a stable biomass concentration and ethanol production rate. These findings highlight the potential of CO-fermentation with acetate augmentation and the importance of preventing oxygen contaminations.
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Affiliation(s)
- Sarah Schulz
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
| | - Bastian Molitor
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany; Cluster of Excellence - Controlling Microbes to Fight Infections, University of Tübingen, Germany
| | - Largus T Angenent
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany; Cluster of Excellence - Controlling Microbes to Fight Infections, University of Tübingen, Germany; AG Angenent, Max Planck Institute for Biology Tübingen, Max Planck Ring 5, 72076 Tübingen, Germany; Department of Biological and Chemical Engineering, Aarhus University, Universitetsbyen 36, 8000 Aarhus C, Denmark; The Novo Nordisk Foundation CO(2) Research Center (CORC), Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus C, Denmark.
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9
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The Role of Microorganisms and Carbon-to-Nitrogen Ratios for Microbial Protein Production from Bioethanol. Appl Environ Microbiol 2022; 88:e0118822. [PMID: 36286523 PMCID: PMC9680612 DOI: 10.1128/aem.01188-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The global protein demand is rapidly increasing at rates that cannot be sustained, with projections showing 78% increased global protein needs by 2050 (361 compared to 202 million ton
protein
/year in 2017). In the absence of dedicated mitigation strategies, the environmental effects of our current food production system (relying on agriculture) are expected to surpass the planetary boundaries—the safe operating space for humanity—by 2050.
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10
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Kang Y, Xiao J, Ding R, Xu K, Zhang T, Tremblay PL. A two-stage process for the autotrophic and mixotrophic conversion of C1 gases into bacterial cellulose. BIORESOURCE TECHNOLOGY 2022; 361:127711. [PMID: 35907600 DOI: 10.1016/j.biortech.2022.127711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Gas fermentation is a well-established process for the conversion of greenhouse gases from industrial wastes into valuable multi-carbon chemicals. Here, a two-stage process was developed to expand the product range of gas fermentation and synthesized the versatile biopolymer bacterial cellulose (BC). In the first stage, the acetogen Clostridium autoethanogenum was cultivated with H2:CO:CO2 and produced ethanol and acetate. In the second stage, BC-synthesizing Komagataeibacter sucrofermentans was grown in the spent medium from gas fermentation. K. sucrofermentans was able to produce BC autotrophically from gas-derived metabolites alone as well as mixotrophically with the addition of exogenous glucose. In these circumstances, 1.31 g/L BC was synthesized with a major energetic contribution from C1 gas fermentation products. Mixotrophic BC characterization reveals unique properties including augmented mechanical strength, porosity, and crystallinity. This proof-of-concept process demonstrates that BC can be produced from gases and holds good potential for the efficient conversion of C1 wastes.
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Affiliation(s)
- Yu Kang
- School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China
| | - Jianxun Xiao
- School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; Shaoxing Institute for Advanced Research, Wuhan University of Technology, Shaoxing 312300, PR China
| | - Ran Ding
- School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China
| | - Kai Xu
- Center for Material Research and Analysis, Wuhan University of Technology, Wuhan 430070, PR China
| | - Tian Zhang
- School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; Shaoxing Institute for Advanced Research, Wuhan University of Technology, Shaoxing 312300, PR China; State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; Sanya Science and Education Innovation Park, Wuhan University of Technology, Sanya 572024, PR China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, PR China; School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
| | - Pier-Luc Tremblay
- School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; Shaoxing Institute for Advanced Research, Wuhan University of Technology, Shaoxing 312300, PR China
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11
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Sun X, Thunuguntla R, Zhang H, Atiyeh H. Biochar amended microbial conversion of C1 gases to ethanol and butanol: Effects of biochar feedstock type and processing temperature. BIORESOURCE TECHNOLOGY 2022; 360:127573. [PMID: 35792327 DOI: 10.1016/j.biortech.2022.127573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Biochar feedstock and production method affects its physicochemical properties and subsequent application. This study investigated the effects of biochar from switchgrass (SGB) and poultry litter (PLB) produced at 350 and 700 °C on alcohol formation using CO:CO2:H2 (40:30:30) by Clostridium carboxidivorans (P7) and C. ragsdalei (P11). Fermentations were performed in 250 mL bottles with a 50 mL working volume at 37 °C. Strains P7 and P11 produced 1.2- to 2.2-fold more alcohol and consumed 1.2- to 1.9-fold more syngas using biochars made at 700 °C compared to 350 °C. Both strains also produced 1.4- to1.9-fold more alcohol with both biochars made at 700 °C compared to control without biochar. Strain P11 produced 1.1- and 1.6-fold more alcohol and fatty acids, respectively, in medium with PLB made at 700 °C compared to strain P7. These results provide guidance towards the selection of biochar type and production temperature to improve syngas fermentation.
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Affiliation(s)
- Xiao Sun
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Rahul Thunuguntla
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA
| | - Hailin Zhang
- Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Hasan Atiyeh
- Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK, USA.
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12
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Benito-Vaquerizo S, Parera Olm I, de Vroet T, Schaap PJ, Sousa DZ, Martins Dos Santos VAP, Suarez-Diez M. Genome-scale metabolic modelling enables deciphering ethanol metabolism via the acrylate pathway in the propionate-producer Anaerotignum neopropionicum. Microb Cell Fact 2022; 21:116. [PMID: 35710409 PMCID: PMC9205015 DOI: 10.1186/s12934-022-01841-1] [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: 04/12/2022] [Accepted: 05/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Microbial production of propionate from diluted streams of ethanol (e.g., deriving from syngas fermentation) is a sustainable alternative to the petrochemical production route. Yet, few ethanol-fermenting propionigenic bacteria are known, and understanding of their metabolism is limited. Anaerotignum neopropionicum is a propionate-producing bacterium that uses the acrylate pathway to ferment ethanol and CO2 to propionate and acetate. In this work, we used computational and experimental methods to study the metabolism of A. neopropionicum and, in particular, the pathway for conversion of ethanol into propionate. RESULTS Our work describes iANEO_SB607, the first genome-scale metabolic model (GEM) of A. neopropionicum. The model was built combining the use of automatic tools with an extensive manual curation process, and it was validated with experimental data from this and published studies. The model predicted growth of A. neopropionicum on ethanol, lactate, sugars and amino acids, matching observed phenotypes. In addition, the model was used to implement a dynamic flux balance analysis (dFBA) approach that accurately predicted the fermentation profile of A. neopropionicum during batch growth on ethanol. A systematic analysis of the metabolism of A. neopropionicum combined with model simulations shed light into the mechanism of ethanol fermentation via the acrylate pathway, and revealed the presence of the electron-transferring complexes NADH-dependent reduced ferredoxin:NADP+ oxidoreductase (Nfn) and acryloyl-CoA reductase-EtfAB, identified for the first time in this bacterium. CONCLUSIONS The realisation of the GEM iANEO_SB607 is a stepping stone towards the understanding of the metabolism of the propionate-producer A. neopropionicum. With it, we have gained insight into the functioning of the acrylate pathway and energetic aspects of the cell, with focus on the fermentation of ethanol. Overall, this study provides a basis to further exploit the potential of propionigenic bacteria as microbial cell factories.
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Affiliation(s)
- Sara Benito-Vaquerizo
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Ivette Parera Olm
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Thijs de Vroet
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands.,Centre for Living Technologies, Alliance TU/e, WUR, UU, UMC Utrecht, Vening Meinesz building C, Princetonlaan 6, Utrecht, 3584 CB, The Netherlands
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands.,Bioprocess Engineering, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, Wageningen, 6708WE, The Netherlands.
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13
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Stark C, Münßinger S, Rosenau F, Eikmanns BJ, Schwentner A. The Potential of Sequential Fermentations in Converting C1 Substrates to Higher-Value Products. Front Microbiol 2022; 13:907577. [PMID: 35722332 PMCID: PMC9204031 DOI: 10.3389/fmicb.2022.907577] [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: 03/29/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Today production of (bulk) chemicals and fuels almost exclusively relies on petroleum-based sources, which are connected to greenhouse gas release, fueling climate change. This increases the urgence to develop alternative bio-based technologies and processes. Gaseous and liquid C1 compounds are available at low cost and often occur as waste streams. Acetogenic bacteria can directly use C1 compounds like CO, CO2, formate or methanol anaerobically, converting them into acetate and ethanol for higher-value biotechnological products. However, these microorganisms possess strict energetic limitations, which in turn pose limitations to their potential for biotechnological applications. Moreover, efficient genetic tools for strain improvement are often missing. However, focusing on the metabolic abilities acetogens provide, they can prodigiously ease these technological disadvantages. Producing acetate and ethanol from C1 compounds can fuel via bio-based intermediates conversion into more energy-demanding, higher-value products, by deploying aerobic organisms that are able to grow with acetate/ethanol as carbon and energy source. Promising new approaches have become available combining these two fermentation steps in sequential approaches, either as separate fermentations or as integrated two-stage fermentation processes. This review aims at introducing, comparing, and evaluating the published approaches of sequential C1 fermentations, delivering a list of promising organisms for the individual fermentation steps and giving an overview of the existing broad spectrum of products based on acetate and ethanol. Understanding of these pioneering approaches allows collecting ideas for new products and may open avenues toward making full use of the technological potential of these concepts for establishment of a sustainable biotechnology.
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Affiliation(s)
- Christina Stark
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Sini Münßinger
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Frank Rosenau
- Institute of Pharmaceutical Biotechnology, University of Ulm, Ulm, Germany
| | - Bernhard J. Eikmanns
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
- *Correspondence: Bernhard J. Eikmanns,
| | - Andreas Schwentner
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
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14
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Bajracharya S, Krige A, Matsakas L, Rova U, Christakopoulos P. Advances in cathode designs and reactor configurations of microbial electrosynthesis systems to facilitate gas electro-fermentation. BIORESOURCE TECHNOLOGY 2022; 354:127178. [PMID: 35436538 DOI: 10.1016/j.biortech.2022.127178] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 06/14/2023]
Abstract
In gas fermentation, a range of chemolithoautotrophs fix single-carbon (C1) gases (CO2 and CO) when H2 or other reductants are available. Microbial electrosynthesis (MES) enables CO2 reduction by generating H2 or reducing equivalents with the sole input of renewable electricity. A combined approach as gas electro-fermentation is attractive for the sustainable production of biofuels and biochemicals utilizing C1 gases. Various platform compounds such as acetate, butyrate, caproate, ethanol, butanol and bioplastics can be produced. However, technological challenges pertaining to the microbe-material interactions such as poor gas-liquid mass transfer, low biomass and biofilm coverage on cathode, low productivities still exist. We are presenting a review on latest developments in MES focusing on the configuration and design of cathodes that can address the challenges and support the gas electro-fermentation. Overall, the opportunities for advancing CO and CO2-based biochemicals and biofuels production in MES with suitable cathode/reactor design are prospected.
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Affiliation(s)
- Suman Bajracharya
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden.
| | - Adolf Krige
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Leonidas Matsakas
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 971-87 Luleå, Sweden
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15
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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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16
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de Lima LA, Ingelman H, Brahmbhatt K, Reinmets K, Barry C, Harris A, Marcellin E, Köpke M, Valgepea K. Faster Growth Enhances Low Carbon Fuel and Chemical Production Through Gas Fermentation. Front Bioeng Biotechnol 2022; 10:879578. [PMID: 35497340 PMCID: PMC9039284 DOI: 10.3389/fbioe.2022.879578] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 03/14/2022] [Indexed: 12/13/2022] Open
Abstract
Gas fermentation offers both fossil carbon-free sustainable production of fuels and chemicals and recycling of gaseous and solid waste using gas-fermenting microbes. Bioprocess development, systems-level analysis of biocatalyst metabolism, and engineering of cell factories are advancing the widespread deployment of the commercialised technology. Acetogens are particularly attractive biocatalysts but effects of the key physiological parameter–specific growth rate (μ)—on acetogen metabolism and the gas fermentation bioprocess have not been established yet. Here, we investigate the μ-dependent bioprocess performance of the model-acetogen Clostridium autoethanogenum in CO and syngas (CO + CO2+H2) grown chemostat cultures and assess systems-level metabolic responses using gas analysis, metabolomics, transcriptomics, and metabolic modelling. We were able to obtain steady-states up to μ ∼2.8 day−1 (∼0.12 h−1) and show that faster growth supports both higher yields and productivities for reduced by-products ethanol and 2,3-butanediol. Transcriptomics data revealed differential expression of 1,337 genes with increasing μ and suggest that C. autoethanogenum uses transcriptional regulation to a large extent for facilitating faster growth. Metabolic modelling showed significantly increased fluxes for faster growing cells that were, however, not accompanied by gene expression changes in key catabolic pathways for CO and H2 metabolism. Cells thus seem to maintain sufficient “baseline” gene expression to rapidly respond to CO and H2 availability without delays to kick-start metabolism. Our work advances understanding of transcriptional regulation in acetogens and shows that faster growth of the biocatalyst improves the gas fermentation bioprocess.
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Affiliation(s)
- Lorena Azevedo de Lima
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Henri Ingelman
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kush Brahmbhatt
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Kristina Reinmets
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | - Craig Barry
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD, Australia
| | | | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD, Australia
| | | | - Kaspar Valgepea
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
- *Correspondence: Kaspar Valgepea,
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17
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Metabolic Engineering Interventions for Sustainable 2,3-Butanediol Production in Gas-Fermenting Clostridium autoethanogenum. mSystems 2022; 7:e0111121. [PMID: 35323044 PMCID: PMC9040633 DOI: 10.1128/msystems.01111-21] [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] [Indexed: 11/20/2022] Open
Abstract
Gas fermentation provides a promising platform to turn low-cost and readily available single-carbon waste gases into commodity chemicals, such as 2,3-butanediol. Clostridium autoethanogenum is usually used as a robust and flexible chassis for gas fermentation. Here, we leveraged constraint-based stoichiometric modeling and kinetic ensemble modeling of the C. autoethanogenum metabolic network to provide a systematic in silico analysis of metabolic engineering interventions for 2,3-butanediol overproduction and low carbon substrate loss in dissipated CO2. Our analysis allowed us to identify and to assess comparatively the expected performances for a wide range of single, double, and triple interventions. Our analysis managed to individuate bottleneck reactions in relevant metabolic pathways when suggesting intervening strategies. Besides recapitulating intuitive and/or previously attempted genetic modifications, our analysis neatly outlined that interventions-at least partially-impinging on by-products branching from acetyl coenzyme A (acetyl-CoA) and pyruvate (acetate, ethanol, amino acids) offer valuable alternatives to the interventions focusing directly on the specific branch from pyruvate to 2,3-butanediol. IMPORTANCE Envisioning value chains inspired by environmental sustainability and circularity in economic models is essential to counteract the alterations in the global natural carbon cycle induced by humans. Recycling carbon-based waste gas streams into chemicals by devising gas fermentation bioprocesses mediated by acetogens of the genus Clostridium is one component of the solution. Carbon monoxide originates from multiple biogenic and abiogenic sources and bears a significant environmental impact. This study aims at identifying metabolic engineering interventions for increasing 2,3-butanediol production and avoiding carbon loss in CO2 dissipation via C. autoethanogenum fermenting a substrate comprising CO and H2. 2,3-Butanediol is a valuable biochemical by-product since, due to its versatility, can be transformed quite easily into chemical compounds such as butadiene, diacetyl, acetoin, and methyl ethyl ketone. These compounds are usable as building blocks to manufacture a vast range of industrially produced chemicals.
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18
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Arslan K, Schoch T, Höfele F, Herrschaft S, Oberlies C, Bengelsdorf F, Veiga MC, Dürre P, Kennes C. Engineering
Acetobacterium woodii
for the production of isopropanol and acetone from carbon dioxide and hydrogen. Biotechnol J 2022; 17:e2100515. [DOI: 10.1002/biot.202100515] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Kübra Arslan
- Chemical Enginering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), BIOENGIN group University of La Coruña Rúa da Fraga 10 La Coruña 15008 Spain
| | - Teresa Schoch
- Institute of Microbiology and Biotechnology University of Ulm Albert‐Einstein‐Allee 11 Ulm 89081 Germany
| | - Franziska Höfele
- Institute of Microbiology and Biotechnology University of Ulm Albert‐Einstein‐Allee 11 Ulm 89081 Germany
| | - Sabrina Herrschaft
- Institute of Microbiology and Biotechnology University of Ulm Albert‐Einstein‐Allee 11 Ulm 89081 Germany
| | - Catarina Oberlies
- Institute of Microbiology and Biotechnology University of Ulm Albert‐Einstein‐Allee 11 Ulm 89081 Germany
| | - Frank Bengelsdorf
- Institute of Microbiology and Biotechnology University of Ulm Albert‐Einstein‐Allee 11 Ulm 89081 Germany
| | - María C. Veiga
- Chemical Enginering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), BIOENGIN group University of La Coruña Rúa da Fraga 10 La Coruña 15008 Spain
| | - Peter Dürre
- Institute of Microbiology and Biotechnology University of Ulm Albert‐Einstein‐Allee 11 Ulm 89081 Germany
| | - Christian Kennes
- Chemical Enginering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), BIOENGIN group University of La Coruña Rúa da Fraga 10 La Coruña 15008 Spain
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19
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Exploiting Aerobic Carboxydotrophic Bacteria for Industrial Biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 180:1-32. [PMID: 34894287 DOI: 10.1007/10_2021_178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Aerobic carboxydotrophic bacteria are a group of microorganisms which possess the unique trait to oxidize carbon monoxide (CO) as sole energy source with molecular oxygen (O2) to produce carbon dioxide (CO2) which subsequently is used for biomass formation via the Calvin-Benson-Bassham cycle. Moreover, most carboxydotrophs are also able to oxidize hydrogen (H2) with hydrogenases to drive the reduction of carbon dioxide in the absence of CO. As several abundant industrial off-gases contain significant amounts of CO, CO2, H2 as well as O2, these bacteria come into focus for industrial application to produce chemicals and fuels from such gases in gas fermentation approaches. Since the group of carboxydotrophic bacteria is rather unknown and not very well investigated, we will provide an overview about their lifestyle and the underlying metabolic characteristics, introduce promising members for industrial application, and give an overview of available genetic engineering tools. We will point to limitations and discuss challenges, which have to be overcome to apply metabolic engineering approaches and to utilize aerobic carboxydotrophs in the industrial environment.
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20
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Ayol A, Peixoto L, Keskin T, Abubackar HN. Reactor Designs and Configurations for Biological and Bioelectrochemical C1 Gas Conversion: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182111683. [PMID: 34770196 PMCID: PMC8583215 DOI: 10.3390/ijerph182111683] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/22/2021] [Accepted: 11/03/2021] [Indexed: 11/16/2022]
Abstract
Microbial C1 gas conversion technologies have developed into a potentially promising technology for converting waste gases (CO2, CO) into chemicals, fuels, and other materials. However, the mass transfer constraint of these poorly soluble substrates to microorganisms is an important challenge to maximize the efficiencies of the processes. These technologies have attracted significant scientific interest in recent years, and many reactor designs have been explored. Syngas fermentation and hydrogenotrophic methanation use molecular hydrogen as an electron donor. Furthermore, the sequestration of CO2 and the generation of valuable chemicals through the application of a biocathode in bioelectrochemical cells have been evaluated for their great potential to contribute to sustainability. Through a process termed microbial chain elongation, the product portfolio from C1 gas conversion may be expanded further by carefully driving microorganisms to perform acetogenesis, solventogenesis, and reverse β-oxidation. The purpose of this review is to provide an overview of the various kinds of bioreactors that are employed in these microbial C1 conversion processes.
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Affiliation(s)
- Azize Ayol
- Department of Environmental Engineering, Dokuz Eylul University, Izmir 35390, Turkey;
| | - Luciana Peixoto
- Centre of Biological Engineering (CEB), University of Minho, 4710-057 Braga, Portugal;
| | - Tugba Keskin
- Department of Environmental Protection Technologies, Izmir Democracy University, Izmir 35140, Turkey;
| | - Haris Nalakath Abubackar
- Chemical Engineering Laboratory, BIOENGIN Group, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), University of A Coruña, 15008 A Coruña, Spain
- Correspondence:
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21
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Bäumler M, Schneider M, Ehrenreich A, Liebl W, Weuster-Botz D. Synthetic co-culture of autotrophic Clostridium carboxidivorans and chain elongating Clostridium kluyveri monitored by flow cytometry. Microb Biotechnol 2021; 15:1471-1485. [PMID: 34669248 PMCID: PMC9049614 DOI: 10.1111/1751-7915.13941] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 01/21/2023] Open
Abstract
Syngas fermentation with acetogens is known to produce mainly acetate and ethanol efficiently. Co-cultures with chain elongating bacteria making use of these products are a promising approach to produce longer-chain alcohols. Synthetic co-cultures with identical initial cell concentrations of Clostridium carboxidivorans and Clostridium kluyveri were studied in batch-operated stirred-tank bioreactors with continuous CO/CO2 -gassing and monitoring of the cell counts of both clostridia by flow cytometry after fluorescence in situ hybridization (FISH-FC). At 800 mbar CO, chain elongation activity was observed at pH 6.0, although growth of C. kluyveri was restricted. Organic acids produced by C. kluyveri were reduced by C. carboxidivorans to the corresponding alcohols butanol and hexanol. This resulted in a threefold increase in final butanol concentration and enabled hexanol production compared with a mono-culture of C. carboxidivorans. At 100 mbar CO, growth of C. kluyveri was improved; however, the capacity of C. carboxidivorans to form alcohols was reduced. Because of the accumulation of organic acids, a constant decay of C. carboxidivorans was observed. The measurement of individual cell concentrations in co-culture established in this study may serve as an effective tool for knowledge-based identification of optimum process conditions for enhanced formation of longer-chain alcohols by clostridial co-cultures.
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Affiliation(s)
- Miriam Bäumler
- Institute of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, Garching, 85748, Germany
| | - Martina Schneider
- Chair of Microbiology, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Str. 4, Freising, Germany
| | - Armin Ehrenreich
- Chair of Microbiology, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Str. 4, Freising, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Str. 4, Freising, Germany
| | - Dirk Weuster-Botz
- Institute of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, Garching, 85748, Germany
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22
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Jia D, He M, Tian Y, Shen S, Zhu X, Wang Y, Zhuang Y, Jiang W, Gu Y. Metabolic Engineering of Gas-Fermenting Clostridium ljungdahlii for Efficient Co-production of Isopropanol, 3-Hydroxybutyrate, and Ethanol. ACS Synth Biol 2021; 10:2628-2638. [PMID: 34549587 DOI: 10.1021/acssynbio.1c00235] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rational design and modification of autotrophic bacteria to efficiently produce high-value chemicals and biofuels are crucial for establishing a sustainable and economically viable process for one-carbon (C1) source utilization, which, however, remains a challenge in metabolic engineering. In this study, autotrophic Clostridium ljungdahlii was metabolically engineered to efficiently co-produce three important bulk chemicals, isopropanol, 3-hydroxybutyrate (3-HB), and ethanol (together, IHE), using syngas (CO2/CO). An artificial isopropanol-producing pathway was first constructed and optimized in C. ljungdahlii to achieve an efficient production of isopropanol and an unexpected product, 3-HB. Based on this finding, an endogenous active dehydrogenase capable of converting acetoacetate to 3-HB was identified in C. ljungdahlii, thereby revealing an efficient 3-HB-producing pathway. The engineered strain was further optimized to reassimilate acetic acid and synthesize 3-HB by introducing heterologous functional genes. Finally, the best-performing strain was able to produce 13.4, 3.0, and 28.4 g/L of isopropanol, 3-HB, and ethanol, respectively, in continuous gas fermentation. Therefore, this work represents remarkable progress in microbial production of bulk chemicals using C1 gases.
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Affiliation(s)
- Dechen Jia
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meiyu He
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yi Tian
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Shaohuang Shen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xianfeng Zhu
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yonghong Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Weihong Jiang
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yang Gu
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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23
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Akermann A, Weiermüller J, Chodorski JN, Nestriepke MJ, Baclig MT, Ulber R. Optimization of bioprocesses with Brewers’ spent grain and
Cellulomonas uda. Eng Life Sci 2021; 22:132-151. [PMID: 35382540 PMCID: PMC8961044 DOI: 10.1002/elsc.202100053] [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: 05/04/2021] [Revised: 07/05/2021] [Accepted: 07/29/2021] [Indexed: 01/09/2023] Open
Abstract
Brewers’ spent grain (BSG) is a low‐value by‐product of the brewing process, which is produced in large quantities every year. In this study, the lignocellulosic feedstock (solid BSG) was used to optimize fermentations with Cellulomonas uda. Under aerobic conditions, maximum cellulase activities of 0.98 nkat∙mL−1, maximum xylanase activities of 5.00 nkat∙mL−1 and cell yields of 0.22 gCells∙gBSG−1 were achieved. Under anaerobic conditions, enzyme activities and cell yields were lower, but valuable liquid products (organic acids, ethanol) were produced with a yield of 0.41 gProd∙gBSG−1. The growth phase of the organisms was monitored by measuring extracellular concentrations of two fluorophores pyridoxin (aerobic) and tryptophan (anaerobic) and by cell count. By combining reductive with anaerobic conditions, the ratio of ethanol to acetate was increased from 1.08 to 1.59 molEtOH∙molAc−1. This ratio was further improved to 9.2 molEtOH∙molAc−1 by lowering the pH from 7.4 to 5.0 without decreasing the final ethanol concentration. A fermentation in a bioreactor with 15 w% BSG instead of 5 w% BSG quadrupled the acetate concentration, whilst ethanol was removed by gas stripping. This study provides various ideas for optimizing and monitoring fermentations with solid substrates, which can support feasibility and incorporation into holistic biorefining approaches in the future.
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Affiliation(s)
- Alexander Akermann
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | - Jens Weiermüller
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | | | - Malte Jakob Nestriepke
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | - Maria Teresa Baclig
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
| | - Roland Ulber
- TU Kaiserslautern Department of Mechanical and Process Engineering Kaiserslautern Germany
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Rodríguez A, Hernández-Herreros N, García JL, Auxiliadora Prieto M. Enhancement of biohydrogen production rate in Rhodospirillum rubrum by a dynamic CO-feeding strategy using dark fermentation. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:168. [PMID: 34362414 PMCID: PMC8343937 DOI: 10.1186/s13068-021-02017-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Rhodospirillum rubrum is a purple non-sulphur bacterium that produces H2 by photofermentation of several organic compounds or by water gas-shift reaction during CO fermentation. Successful strategies for both processes have been developed in light-dependent systems. This work explores a dark fermentation bioprocess for H2 production from water using CO as the electron donor. RESULTS The study of the influence of the stirring and the initial CO partial pressure (pCO) demonstrated that the process was inhibited at pCO of 1.00 atm. Optimal pCO value was established in 0.60 atm. CO dose adaptation to bacterial growth in fed-batch fermentations increased the global rate of H2 production, yielding 27.2 mmol H2 l-1 h-1 and reduced by 50% the operation time. A kinetic model was proposed to describe the evolution of the molecular species involved in gas and liquid phases in a wide range of pCO conditions from 0.10 to 1.00 atm. CONCLUSIONS Dark fermentation in R. rubrum expands the ways to produce biohydrogen from CO. This work optimizes this bioprocess at lab-bioreactor scale studying the influence of the stirring speed, the initial CO partial pressure and the operation in batch and fed-batch regimes. Dynamic CO supply adapted to the biomass growth enhances the productivity reached in darkness by other strategies described in the literature, being similar to that obtained under light continuous syngas fermentations. The kinetic model proposed describes all the conditions tested.
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Affiliation(s)
- Alberto Rodríguez
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐of the Spanish National Research Council (SusPlast‐CSIC), Madrid, Spain
- Polymer Biotechnology Group, Department of Plant and Microbial Biotechnology, Biological Research Center, Margarita Salas”-CSIC, 28040 Madrid, Spain
| | - Natalia Hernández-Herreros
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐of the Spanish National Research Council (SusPlast‐CSIC), Madrid, Spain
- Polymer Biotechnology Group, Department of Plant and Microbial Biotechnology, Biological Research Center, Margarita Salas”-CSIC, 28040 Madrid, Spain
| | - José L. García
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐of the Spanish National Research Council (SusPlast‐CSIC), Madrid, Spain
- Environmental Biotechnology Group, Department of Plant and Microbial Biotechnology, Biological Research Center, Margarita Salas”-CSIC 28040, Madrid, Spain
| | - M. Auxiliadora Prieto
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐of the Spanish National Research Council (SusPlast‐CSIC), Madrid, Spain
- Polymer Biotechnology Group, Department of Plant and Microbial Biotechnology, Biological Research Center, Margarita Salas”-CSIC, 28040 Madrid, Spain
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Grimalt-Alemany A, Etler C, Asimakopoulos K, Skiadas IV, Gavala HN. ORP control for boosting ethanol productivity in gas fermentation systems and dynamics of redox cofactor NADH/NAD+ under oxidative stress. J CO2 UTIL 2021. [DOI: 10.1016/j.jcou.2021.101589] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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26
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Wood JC, Grové J, Marcellin E, Heffernan JK, Hu S, Yuan Z, Virdis B. Strategies to improve viability of a circular carbon bioeconomy-A techno-economic review of microbial electrosynthesis and gas fermentation. WATER RESEARCH 2021; 201:117306. [PMID: 34153823 DOI: 10.1016/j.watres.2021.117306] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/30/2021] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
Abstract
A circular carbon bioeconomy has potential to halt atmospheric accumulation of greenhouse gases causing climate change and sustainably produce chemical, agricultural and fuel products. Here, we report application of a simplified technoeconomic assessment to critically review two approaches in this space - microbial electrosynthesis and gas fermentation. For microbial electrosynthesis, decoupling of surface-dependant abiotic process for electron delivery from volume-dependant biotic carbon fixation, is shown as the only economically viable strategy to scale-up due to comparatively low biofilm electron consumption rate. This is effectively an electrolyser-assisted gas fermentation system. Targeting high-value products, such as protein for human food consumption is one of the few pathways forward for electrolyser-assisted gas fermentation. Alternatively, gas fermentation of reformed biogas presents an interesting and potentially more sustainable implementation pathway to improve economic viability of chemicals. This critical review suggests linking water treatment resource recovery with gas fermentation is attractive for bioplastics and butanol in terms of competitiveness and market demand.
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Affiliation(s)
- Jamin C Wood
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Johannes Grové
- Energy & Poverty Group, School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia; Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, QLD 4072, Australia
| | - James K Heffernan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bernardino Virdis
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
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Process Engineering Aspects for the Microbial Conversion of C1 Gases. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 180:33-56. [PMID: 34291298 DOI: 10.1007/10_2021_172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Industrially applied bioprocesses for the reduction of C1 gases (CO2 and/or CO) are based in particular on (syn)gas fermentation with acetogenic bacteria and on photobioprocesses with microalgae. In each case, process engineering characteristics of the autotrophic microorganisms are specified and process engineering aspects for improving gas and electron supply are summarized before suitable bioreactor configurations are discussed for the production of organic products under given economic constraints. Additionally, requirements for the purity of C1 gases are summarized briefly. Finally, similarities and differences in microbial CO2 valorization are depicted comparing gas fermentations with acetogenic bacteria and photobioprocesses with microalgae.
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Debabov VG. Acetogens: Biochemistry, Bioenergetics, Genetics, and Biotechnological Potential. Microbiology (Reading) 2021. [DOI: 10.1134/s0026261721030024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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30
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Capture and Reuse of Carbon Dioxide (CO2) for a Plastics Circular Economy: A Review. Processes (Basel) 2021. [DOI: 10.3390/pr9050759] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Plastic production has been increasing at enormous rates. Particularly, the socioenvironmental problems resulting from the linear economy model have been widely discussed, especially regarding plastic pieces intended for single use and disposed improperly in the environment. Nonetheless, greenhouse gas emissions caused by inappropriate disposal or recycling and by the many production stages have not been discussed thoroughly. Regarding the manufacturing processes, carbon dioxide is produced mainly through heating of process streams and intrinsic chemical transformations, explaining why first-generation petrochemical industries are among the top five most greenhouse gas (GHG)-polluting businesses. Consequently, the plastics market must pursue full integration with the circular economy approach, promoting the simultaneous recycling of plastic wastes and sequestration and reuse of CO2 through carbon capture and utilization (CCU) strategies, which can be employed for the manufacture of olefins (among other process streams) and reduction of fossil-fuel demands and environmental impacts. Considering the previous remarks, the present manuscript’s purpose is to provide a review regarding CO2 emissions, capture, and utilization in the plastics industry. A detailed bibliometric review of both the scientific and the patent literature available is presented, including the description of key players and critical discussions and suggestions about the main technologies. As shown throughout the text, the number of documents has grown steadily, illustrating the increasing importance of CCU strategies in the field of plastics manufacture.
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31
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Wirth S, Dürre P. Investigation of putative genes for the production of medium-chained acids and alcohols in autotrophic acetogenic bacteria. Metab Eng 2021; 66:296-307. [PMID: 33894339 DOI: 10.1016/j.ymben.2021.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/06/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022]
Abstract
Gas fermentation is a technology for producing platform chemicals as well as fuels and one of the most promising alternatives to petrochemicals. Medium-chained acids and alcohols such as hexanoate and hexanol are particularly interesting due to their versatile application. This study elucidated the pathway of chain elongation in native C6 compound-producing acetogens. Essential genes of Clostridium carboxidivorans for synthesis of medium-chained acids and alcohols were identified in order to demonstrate their catalytic activity in the acetogenic model organism Acetobacterium woodii. Two such gene clusters were identified, which are responsible for conversion of acetyl-CoA to butyryl-CoA by reverse β-oxidation. Using RT-PCR it could be demonstrated that only genes of cluster 1 are expressed constitutively with simultaneous formation of C6 compounds. Based on genes from C. carboxidivorans, a modular hexanoyl-CoA synthesis (hcs) plasmid system was constructed and transferred into A. woodii. With the recombinant A. woodii strains AWO [pPta_hcs1], AWO [pPta_hcs2], AWO [pTet_hcs1], and AWO [pTet_hcs2] butyrate and hexanoate production under heterotrophic (1.22-4.15 mM hexanoate) and autotrophic conditions (0.48-1.56 mM hexanoate) with both hcs clusters could be detected. hcs Cluster 1 from C. carboxidivorans was transferred into the ABE-fermenting strain Clostridium saccharoperbutylacetonicum as well. For further analysis, genes were also cloned into the hcs plasmid system individually. The resulting recombinant C. saccharoperbutylacetonicum strains with just individual genes neither produced hexanoate nor hexanol, but the strains containing the entire gene cluster were capable of chain elongation. A production of 0.8 mM hexanoate and 5.2 mM hexanol in the fermentation with glucose could be observed.
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Affiliation(s)
- Steffen Wirth
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, D-89081, Ulm, Germany.
| | - Peter Dürre
- Institut für Mikrobiologie und Biotechnologie, Universität Ulm, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
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32
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Novak K, Neuendorf CS, Kofler I, Kieberger N, Klamt S, Pflügl S. Blending industrial blast furnace gas with H 2 enables Acetobacterium woodii to efficiently co-utilize CO, CO 2 and H 2. BIORESOURCE TECHNOLOGY 2021; 323:124573. [PMID: 33360948 DOI: 10.1016/j.biortech.2020.124573] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
In this study, the impact of gas composition (i.e. CO, CO2 and H2 partial pressures) on CO2 utilization, growth, and acetate production was investigated in batch and continuous cultures of A. woodii. Based on an industrial blast furnace gas, H2 blending was used to study the impact of H2 availability on CO2 fixation alone and together with CO using idealized gas streams. With H2 available as an additional energy source, net CO2 fixation and CO, CO2 and H2 co-utilization was achieved in gas-limited fermentations. Using industrial blast furnace gas, up to 15.1 g l-1 acetate were produced in continuous cultures. Flux balance analysis showed that intracellular fluxes and total ATP production were dependent on the availability of H2 and CO. Overall, H2 blending was shown to be a suitable control strategy for gas fermentations and demonstrated that A. woodii is an interesting host for CO2 fixation from industrial gas streams.
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Affiliation(s)
- Katharina Novak
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
| | - Christian Simon Neuendorf
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
| | | | - Nina Kieberger
- voestalpine Stahl GmbH, voestalpine-Straße 3, 4020 Linz, Austria.
| | - Steffen Klamt
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany.
| | - Stefan Pflügl
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
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33
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Cha S, Lim HG, Kwon S, Kim DH, Kang CW, Jung GY. Design of mutualistic microbial consortia for stable conversion of carbon monoxide to value-added chemicals. Metab Eng 2021; 64:146-153. [PMID: 33571657 DOI: 10.1016/j.ymben.2021.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/22/2020] [Accepted: 02/02/2021] [Indexed: 12/31/2022]
Abstract
Carbon monoxide (CO) is a promising carbon source for producing value-added biochemicals via microbial fermentation. However, its microbial conversion has been challenging because of difficulties in genetic engineering of CO-utilizing microorganisms and, more importantly, maintaining CO consumption which is negatively affected by the toxicity of CO and accumulated byproducts. To overcome these issues, we devised mutualistic microbial consortia, co-culturing Eubacterium limosum and genetically engineered Escherichia coli for the production of 3-hydroxypropionic acid (3-HP) and itaconic acid (ITA). During the co-culture, E. limosum assimilated CO and produced acetate, a toxic by-product, while E. coli utilized acetate as a sole carbon source. We found that this mutualistic interaction dramatically stabilized and improved CO consumption of E. limosum compared to monoculture. Consequently, the improved CO consumption allowed successful production of 3-HP and ITA from CO. This study is the first demonstration of value-added biochemical production from CO using a microbial consortium. Moreover, it suggests that synthetic mutualistic microbial consortium can serve as a powerful platform for the valorization of CO.
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Affiliation(s)
- Sanghak Cha
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Hyun Gyu Lim
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Seokmu Kwon
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Dong-Hwan Kim
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Chae Won Kang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Gyoo Yeol Jung
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea; School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-RoNam-Gu, Pohang, Gyeongbuk, 37673, Republic of Korea.
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34
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Ghysels S, Buffel S, Rabaey K, Ronsse F, Ganigué R. Biochar and activated carbon enhance ethanol conversion and selectivity to caproic acid by Clostridium kluyveri. BIORESOURCE TECHNOLOGY 2021; 319:124236. [PMID: 33254460 DOI: 10.1016/j.biortech.2020.124236] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 06/12/2023]
Abstract
Syngas from biomass or steel mills can be fermented into a dilute stream of ethanol and acetic acid, which requires energy intensive distillation for product recovery. This can be circumvented by selective secondary fermentation of the syngas fermentation effluent to caproic acid as easier recoverable platform chemical with Clostridium kluyveri. Here, we explore the impact of biochar and activated carbon on this process. Changes during the fermentation with biochar or activated carbon were monitored, different doses were tested and the recyclability of biochar and activated carbon was assessed. Biochar decreased the lag phase and increased the caproic acid production rate (up to 0.50 g·L-1·h-1). Upon recycling for subsequent fermentation, biochar retained this property largely. Activated carbon addition, especially at high dose, could potentially increase the conversion and selectivity towards caproic acid to 14.15 g·L-1 (control: 11.01 g·L-1) and 92% (control: 84%), respectively.
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Affiliation(s)
- Stef Ghysels
- Thermochemical Conversion of Biomass Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium; Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Sara Buffel
- Thermochemical Conversion of Biomass Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium; Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Korneel Rabaey
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure links 653, B-9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Belgium
| | - Frederik Ronsse
- Thermochemical Conversion of Biomass Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure links 653, B-9000 Ghent, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Belgium.
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Alves JI, Visser M, Arantes AL, Nijsse B, Plugge CM, Alves MM, Stams AJM, Sousa DZ. Effect of Sulfate on Carbon Monoxide Conversion by a Thermophilic Syngas-Fermenting Culture Dominated by a Desulfofundulus Species. Front Microbiol 2020; 11:588468. [PMID: 33304333 PMCID: PMC7701048 DOI: 10.3389/fmicb.2020.588468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/19/2020] [Indexed: 11/13/2022] Open
Abstract
A syngas-degrading enrichment culture, culture T-Syn, was dominated by a bacterium closely related to Desulfofundulus australicus strain AB33T (98% 16S rRNA gene sequence identity). Culture T-Syn could convert high CO concentrations (from pCO ≈ 34 kPa to pCO ≈ 170 kPa), both in the absence and in the presence of sulfate as external electron acceptor. The products formed from CO conversion were H2 and acetate. With sulfate, a lower H2/acetate ratio was observed in the product profile, but CO conversion rates were similar to those in the absence of sulfate. The ability of D. australicus strain AB33T to use CO was also investigated. D. australicus strain AB33T uses up to 40% CO (pCO ≈ 68 kPa) with sulfate and up to 20% CO (pCO ≈ 34 kPa) without sulfate. Comparison of the metagenome-assembled genome (MAG) of the Desulfofundulus sp. from T-Syn culture with the genome of D. australicus strain AB33T revealed high similarity, with an ANI value of 99% and only 32 unique genes in the genome of the Desulfofundulus sp. T-Syn. So far, only Desulfotomaculum nigrificans strain CO-1-SRB had been described to grow with CO with and without sulfate. This work further shows the carboxydotrophic potential of Desulfofundulus genus for CO conversion, both in sulfate-rich and low-sulfate environments.
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Affiliation(s)
- Joana I Alves
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Michael Visser
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Ana L Arantes
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Bart Nijsse
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, Netherlands
| | - Caroline M Plugge
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - M Madalena Alves
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Alfons J M Stams
- Centre of Biological Engineering, University of Minho, Braga, Portugal.,Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Diana Z Sousa
- Centre of Biological Engineering, University of Minho, Braga, Portugal.,Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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Biermann M, Montañés RM, Normann F, Johnsson F. Carbon Allocation in Multi-Product Steel Mills That Co‐process Biogenic and Fossil Feedstocks and Adopt Carbon Capture Utilization and Storage Technologies. FRONTIERS IN CHEMICAL ENGINEERING 2020. [DOI: 10.3389/fceng.2020.596279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This work investigates the effects of carbon allocation on the emission intensities of low-carbon products cogenerated in facilities that co‐process biogenic and fossil feedstocks and apply the carbon capture utilization and storage technology. Thus, these plants simultaneously sequester CO2 and synthesize fuels or chemicals. We consider an integrated steel mill that injects biomass into the blast furnace, captures CO2 for storage, and ferments CO into ethanol from the blast furnace gas. We examine two schemes to allocate the CO2 emissions avoided [due to the renewable feedstock share (biomass) and CO2 capture and storage (CCS)] to the products of steel, ethanol, and electricity (generated through the combustion of steel mill waste gases): 1) allocation by (carbon) mass, which represents actual carbon flows, and 2) a free-choice attribution that maximizes the renewable content allocated to electricity and ethanol. With respect to the chosen assumptions on process performance and heat integration, we find that allocation by mass favors steel and is unlikely to yield an ethanol product that fulfills the Renewable Energy Directive (RED) biofuel criterion (65% emission reduction relative to a fossil comparator), even when using renewable electricity and applying CCS to the blast furnace gas prior to CO conversion into ethanol and electricity. In contrast, attribution fulfills the criterion and yields bioethanol for electricity grid intensities <180 gCO2/kWhel without CCS and yields bioethanol for grid intensities up to 800 gCO2/kWhel with CCS. The overall emissions savings are up to 27 and 47% in the near-term and long-term future, respectively. The choice of the allocation scheme greatly affects the emissions intensities of cogenerated products. Thus, the set of valid allocation schemes determines the extent of flexibility that manufacturers have in producing low-carbon products, which is relevant for industries whose product target sectors that value emissions differently. We recommend that policymakers consider the emerging relevance of co‐processing in nonrefining facilities. Provided there is no double-accounting of emissions, policies should contain a reasonable degree of freedom in the allocation of emissions savings to low-carbon products, so as to promote the sale of these savings, thereby making investments in mitigation technologies more attractive to stakeholders.
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37
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Geinitz B, Hüser A, Mann M, Büchs J. Gas Fermentation Expands the Scope of a Process Network for Material Conversion. CHEM-ING-TECH 2020. [DOI: 10.1002/cite.202000086] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Bertram Geinitz
- RWTH Aachen University, AVT – Biochemical Engineering Forckenbeckstraße 51 52074 Aachen Germany
| | - Aline Hüser
- RWTH Aachen University, AVT – Biochemical Engineering Forckenbeckstraße 51 52074 Aachen Germany
| | - Marcel Mann
- RWTH Aachen University, AVT – Biochemical Engineering Forckenbeckstraße 51 52074 Aachen Germany
| | - Jochen Büchs
- RWTH Aachen University, AVT – Biochemical Engineering Forckenbeckstraße 51 52074 Aachen Germany
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38
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Xia PF, Casini I, Schulz S, Klask CM, Angenent LT, Molitor B. Reprogramming Acetogenic Bacteria with CRISPR-Targeted Base Editing via Deamination. ACS Synth Biol 2020; 9:2162-2171. [PMID: 32610012 DOI: 10.1021/acssynbio.0c00226] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Acetogenic bacteria are rising in popularity as chassis microbes for biotechnology due to their capability of converting inorganic one-carbon (C1) gases to organic chemicals. To fully uncover the potential of acetogenic bacteria, synthetic biology tools are imperative to either engineer designed functions or to interrogate the physiology. Here, we report a genome-editing tool at a one-nucleotide resolution, namely base editing, for acetogenic bacteria based on CRISPR-targeted deamination. This tool combines nuclease deactivated Cas9 with activation-induced cytidine deaminase to enable cytosine-to-thymine substitution without DNA cleavage, homology-directed repair, and donor DNA, which are generally the bottlenecks for applying conventional CRISPR-Cas systems in bacteria. We designed and validated a modularized base-editing tool in the model acetogenic bacterium Clostridium ljungdahlii. The editing principles were investigated, and an in-silico analysis revealed the capability of base editing across the genome and the potential for off-target events. Moreover, genes related to acetate and ethanol production were disrupted individually by installing premature STOP codons to reprogram carbon flux toward improved acetate production. This resulted in engineered C. ljungdahlii strains with the desired phenotypes and stable genotypes. Our base-editing tool promotes the application and research in acetogenic bacteria and provides a blueprint to upgrade CRISPR-Cas-based genome editing in bacteria in general.
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Affiliation(s)
- Peng-Fei Xia
- Environmental Biotechnology Group, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany
| | - Isabella Casini
- Environmental Biotechnology Group, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany
| | - Sarah Schulz
- Environmental Biotechnology Group, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany
| | - Christian-Marco Klask
- Environmental Biotechnology Group, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany
| | - Largus T. Angenent
- Environmental Biotechnology Group, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany
- AG Angenent, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Bastian Molitor
- Environmental Biotechnology Group, Center for Applied Geosciences, University of Tübingen, 72074 Tübingen, Germany
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Ethanol Metabolism Dynamics in Clostridium ljungdahlii Grown on Carbon Monoxide. Appl Environ Microbiol 2020; 86:AEM.00730-20. [PMID: 32414802 DOI: 10.1128/aem.00730-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/11/2020] [Indexed: 01/10/2023] Open
Abstract
Bioethanol production from syngas using acetogenic bacteria has attracted considerable attention in recent years. However, low ethanol yield is the biggest challenge that prevents the commercialization of syngas fermentation into biofuels using microbial catalysts. The present study demonstrated that ethanol metabolism plays an important role in recycling NADH/NAD+ during autotrophic growth. Deletion of bifunctional aldehyde/alcohol dehydrogenase (adhE) genes leads to significant growth deficiencies in gas fermentation. Using specific fermentation technology in which the gas pressure and pH were constantly controlled at 0.1 MPa and 6.0, respectively, we revealed that ethanol was formed during the exponential phase, closely accompanied by biomass production. Then, ethanol was oxidized to acetate via the aldehyde ferredoxin oxidoreductase pathway in Clostridium ljungdahlii A metabolic experiment using 13C-labeled ethanol and acetate, redox balance analysis, and comparative transcriptomic analysis demonstrated that ethanol production and reuse shared the metabolic pathway but occurred at different growth phases.IMPORTANCE Ethanol production from carbon monoxide (CO) as a carbon and energy source by Clostridium ljungdahlii and "Clostridium autoethanogenum" is currently being commercialized. During gas fermentation, ethanol synthesis is NADH-dependent. However, ethanol oxidation and its regulatory mechanism remain incompletely understood. Energy metabolism analysis demonstrated that reduced ferredoxin is the sole source of NADH formation by the Rnf-ATPase system, which provides ATP for cell growth during CO fermentation. Therefore, ethanol production is tightly linked to biomass production (ATP production). Clarification of the mechanism of ethanol oxidation and biosynthesis can provide an important reference for generating high-ethanol-yield strains of C. ljungdahlii in the future.
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Siebert D, Busche T, Metz AY, Smaili M, Queck BAW, Kalinowski J, Eikmanns BJ. Genetic Engineering of Oligotropha carboxidovorans Strain OM5-A Promising Candidate for the Aerobic Utilization of Synthesis Gas. ACS Synth Biol 2020; 9:1426-1440. [PMID: 32379961 DOI: 10.1021/acssynbio.0c00098] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Due to climate change and worldwide pollution, development of highly sustainable routes for industrial production of basic and specialty chemicals is critical nowadays. One possible approach is the use of CO2- and CO-utilizing microorganisms in biotechnological processes to produce value-added compounds from synthesis gas (mixtures of CO2, CO, and H2) or from C1-containing industrial waste gases. Such syngas fermentation processes have already been established, e.g., biofuel production using strictly anaerobic acetogenic bacteria. However, aerobic processes may be favorable for the formation of more costly (ATP-intensive) products. Oligotropha carboxidovorans strain OM5 is an aerobic carboxidotrophic bacterium and potentially a promising candidate for such processes. We here performed RNA-Seq analysis comparing cells of this organism grown heterotrophically with acetate or autotrophically with CO2, CO, and H2 as carbon and energy source and found a variety of chromosomally and of native plasmid-encoded genes to be highly differentially expressed. In particular, genes and gene clusters encoding proteins required for autotrophic growth (CO2 fixation via Calvin-Benson-Bassham cycle), for CO metabolism (CO dehydrogenase), and for H2 utilization (hydrogenase), all located on megaplasmid pHCG3, were much higher expressed during autotrophic growth with synthesis gas. Furthermore, we successfully established reproducible transformation of O. carboxidovorans via electroporation and developed gene deletion and gene exchange protocols via two-step recombination, enabling inducible and stable expression of heterologous genes as well as construction of defined mutants of this organism. Thus, this study marks an important step toward metabolic engineering of O. carboxidovorans and effective utilization of C1-containing gases with this organism.
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Affiliation(s)
- Daniel Siebert
- Institute of Microbiology and Biotechnology, Ulm University, 89069 Ulm, Germany
- Microbial Biotechnology, Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, 94315 Straubing, Germany
| | - Tobias Busche
- Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany
| | - Aline Y. Metz
- Institute of Microbiology and Biotechnology, Ulm University, 89069 Ulm, Germany
| | - Medina Smaili
- Institute of Microbiology and Biotechnology, Ulm University, 89069 Ulm, Germany
| | - Bastian A. W. Queck
- Institute of Microbiology and Biotechnology, Ulm University, 89069 Ulm, Germany
| | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany
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Chu N, Liang Q, Jiang Y, Zeng RJ. Microbial electrochemical platform for the production of renewable fuels and chemicals. Biosens Bioelectron 2020; 150:111922. [DOI: 10.1016/j.bios.2019.111922] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/23/2019] [Accepted: 11/25/2019] [Indexed: 12/01/2022]
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Arantes AL, Moreira JPC, Diender M, Parshina SN, Stams AJM, Alves MM, Alves JI, Sousa DZ. Enrichment of Anaerobic Syngas-Converting Communities and Isolation of a Novel Carboxydotrophic Acetobacterium wieringae Strain JM. Front Microbiol 2020; 11:58. [PMID: 32082285 PMCID: PMC7006291 DOI: 10.3389/fmicb.2020.00058] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/13/2020] [Indexed: 11/13/2022] Open
Abstract
Syngas is a substrate for the anaerobic bioproduction of fuels and valuable chemicals. In this study, anaerobic sludge was used for microbial enrichments with synthetic syngas and acetate as main substrates. The objectives of this study were to identify microbial networks (in enrichment cultures) for the conversion of syngas to added-value products, and to isolate robust, non-fastidious carboxydotrophs. Enrichment cultures produced methane and propionate, this last one an unusual product from syngas fermentation. A bacterium closely related to Acetobacterium wieringae was identified as most prevalent (87% relative abundance) in the enrichments. Methanospirillum sp. and propionate-producing bacteria clustering within the genera Anaerotignum and Pelobacter were also found. Further on, strain JM, was isolated and was found to be 99% identical (16S rRNA gene) to A. wieringae DSM 1911T. Digital DNA-DNA hybridization (dDDH) value between the genomes of strain JM and A. wieringae was 77.1%, indicating that strain JM is a new strain of A. wieringae. Strain JM can grow on carbon monoxide (100% CO, total pressure 170 kPa) without yeast extract or formate, producing mainly acetate. Remarkably, conversion of CO by strain JM showed shorter lag phase than in cultures of A. wieringae DSM 1911T, and about four times higher amount of CO was consumed in 7 days. Genome analysis suggests that strain JM uses the Wood-Ljungdahl pathway for the conversion of one carbon compounds (CO, formate, CO2/H2). Genes encoding bifurcational enzyme complexes with similarity to the bifurcational formate dehydrogenase (Fdh) of Clostridium autoethanogenum are present, and possibly relate to the higher tolerance to CO of strain JM compared to other Acetobacterium species. A. wieringae DSM 1911T grew on CO in medium containing 1 mM formate.
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Affiliation(s)
- Ana L Arantes
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - João P C Moreira
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Martijn Diender
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Sofiya N Parshina
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Laboratory of Microbiology of Anthropogenic Habitats of Winogradsky Institute of Microbiology, Federal State Institution (Fundamentals of Biotechnology) of the Russian Academy of Sciences, Moscow, Russia
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands.,Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - M Madalena Alves
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Joana I Alves
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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Almeida Benalcázar E, Noorman H, Maciel Filho R, Posada JA. Modeling ethanol production through gas fermentation: a biothermodynamics and mass transfer-based hybrid model for microbial growth in a large-scale bubble column bioreactor. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:59. [PMID: 32231709 PMCID: PMC7102449 DOI: 10.1186/s13068-020-01695-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/05/2020] [Indexed: 05/08/2023]
Abstract
BACKGROUND Ethanol production through fermentation of gas mixtures containing CO, CO2 and H2 has just started operating at commercial scale. However, quantitative schemes for understanding and predicting productivities, yields, mass transfer rates, gas flow profiles and detailed energy requirements have been lacking in literature; such are invaluable tools for process improvements and better systems design. The present study describes the construction of a hybrid model for simulating ethanol production inside a 700 m3 bubble column bioreactor fed with gas of two possible compositions, i.e., pure CO and a 3:1 mixture of H2 and CO2. RESULTS Estimations made using the thermodynamics-based black-box model of microbial reactions on substrate threshold concentrations, biomass yields, as well as CO and H2 maximum specific uptake rates agreed reasonably well with data and observations reported in literature. According to the bioreactor simulation, there is a strong dependency of process performance on mass transfer rates. When mass transfer coefficients were estimated using a model developed from oxygen transfer to water, ethanol productivity reached 5.1 g L-1 h-1; when the H2/CO2 mixture is fed to the bioreactor, productivity of CO fermentation was 19% lower. Gas utilization reached 23 and 17% for H2/CO2 and CO fermentations, respectively. If mass transfer coefficients were 100% higher than those estimated, ethanol productivity and gas utilization may reach 9.4 g L-1 h-1 and 38% when feeding the H2/CO2 mixture at the same process conditions. The largest energetic requirements for a complete manufacturing plant were identified for gas compression and ethanol distillation, being higher for CO fermentation due to the production of CO2. CONCLUSIONS The thermodynamics-based black-box model of microbial reactions may be used to quantitatively assess and consolidate the diversity of reported data on CO, CO2 and H2 threshold concentrations, biomass yields, maximum substrate uptake rates, and half-saturation constants for CO and H2 for syngas fermentations by acetogenic bacteria. The maximization of ethanol productivity in the bioreactor may come with a cost: low gas utilization. Exploiting the model flexibility, multi-objective optimizations of bioreactor performance might reveal how process conditions and configurations could be adjusted to guide further process development.
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Affiliation(s)
- Eduardo Almeida Benalcázar
- Department of Product and Process Development, Faculty of Chemical Engineering, State University of Campinas, Av. Albert Einstein 500, Cidade Universitária, Campinas, SP 13083-852 Brazil
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Henk Noorman
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- DSM Biotechnology Center, A. Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Rubens Maciel Filho
- Department of Product and Process Development, Faculty of Chemical Engineering, State University of Campinas, Av. Albert Einstein 500, Cidade Universitária, Campinas, SP 13083-852 Brazil
| | - John A. Posada
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Stoll IK, Boukis N, Sauer J. Syngas Fermentation to Alcohols: Reactor Technology and Application Perspective. CHEM-ING-TECH 2020. [DOI: 10.1002/cite.201900118] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- I. Katharina Stoll
- Karlsruhe Institute of Technology (KIT)Institute of Catalysis Research and Technology (IKFT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Nikolaos Boukis
- Karlsruhe Institute of Technology (KIT)Institute of Catalysis Research and Technology (IKFT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Jörg Sauer
- Karlsruhe Institute of Technology (KIT)Institute of Catalysis Research and Technology (IKFT) Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
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Runikhina SA, Afanasyev OI, Biriukov K, Perekalin DS, Klussmann M, Chusov D. Aldehydes as Alkylating Agents for Ketones. Chemistry 2019; 25:16225-16229. [PMID: 31603584 DOI: 10.1002/chem.201904605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Indexed: 11/06/2022]
Abstract
Common and non-toxic aldehydes are proposed as reagents for alkylation of ketones instead of carcinogenic alkyl halides. The developed reductive alkylation reaction proceeds in the presence of the commercially available ruthenium catalyst [(cymene)RuCl2 ]2 (as low as 250 ppm) and carbon monoxide as the reducing agent. The reaction works well for a broad substrate scope, including aromatic and aliphatic aldehydes and ketones. It can be carried out without a solvent and often gives nearly quantitative yields of the products. This straightforward and cost-effective method is promising not only for laboratory application but also for industry, which produces carbon monoxide as a large-scale waste product.
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Affiliation(s)
- Sofiya A Runikhina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991, Moscow, Russia
| | - Oleg I Afanasyev
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991, Moscow, Russia
| | - Klim Biriukov
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991, Moscow, Russia
| | - Dmitry S Perekalin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991, Moscow, Russia.,G.V. Plekhanov Russian University of Economics, 36 Stremyanny Per., 117997, Moscow, Russia
| | - Martin Klussmann
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Denis Chusov
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova St. 28, 119991, Moscow, Russia.,G.V. Plekhanov Russian University of Economics, 36 Stremyanny Per., 117997, Moscow, Russia
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Metabolic shift induced by synthetic co-cultivation promotes high yield of chain elongated acids from syngas. Sci Rep 2019; 9:18081. [PMID: 31792266 PMCID: PMC6889307 DOI: 10.1038/s41598-019-54445-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/29/2019] [Indexed: 11/08/2022] Open
Abstract
Bio-catalytic processes for sustainable production of chemicals and fuels receive increased attention within the concept of circular economy. Strategies to improve these production processes include genetic engineering of bio-catalysts or process technological optimization. Alternatively, synthetic microbial co-cultures can be used to enhance production of chemicals of interest. It remains often unclear however how microbe to microbe interactions affect the overall production process and how this can be further exploited for application. In the present study we explored the microbial interaction in a synthetic co-culture of Clostridium autoethanogenum and Clostridium kluyveri, producing chain elongated products from carbon monoxide. Monocultures of C. autoethanogenum converted CO to acetate and traces of ethanol, while during co-cultivation with C. kluyveri, it shifted its metabolism significantly towards solventogenesis. In C. autoethanogenum, expression of the genes involved in the central carbon- and energy-metabolism remained unchanged during co-cultivation compared to monoculture condition. Therefore the shift in the metabolic flux of C. autoethanogenum appears to be regulated by thermodynamics, and results from the continuous removal of ethanol by C. kluyveri. This trait could be further exploited, driving the metabolism of C. autoethanogenum to solely ethanol formation during co-cultivation, resulting in a high yield of chain elongated products from CO-derived electrons. This research highlights the important role of thermodynamic interactions in (synthetic) mixed microbial communities and shows that this can be exploited to promote desired conversions.
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Tsygankov AA, Makarova M, Afanasyev OI, Kashin AS, Naumkin AV, Loginov DA, Chusov D. Reductive Amidation without an External Hydrogen Source Using Rhodium on Carbon Matrix as a Catalyst. ChemCatChem 2019. [DOI: 10.1002/cctc.201901465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Alexey A. Tsygankov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
| | - Maria Makarova
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
- Higher Chemical CollegeDmitry Mendeleev University of Chemical Technology of Russia Miusskaya sq. 9 Moscow 125047 Russia
| | - Oleg I. Afanasyev
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
| | - Alexey S. Kashin
- Zelinsky Institute of Organic ChemistryRussian Academy of Sciences Leninsky Prospekt 47 Moscow 119991 Russia
| | - Alexander V. Naumkin
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
- Moscow Institute of Physics and TechnologyState University Institutskiy Pereulok 9 Dolgoprudny 141701 Russia
| | - Dmitry A. Loginov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
| | - Denis Chusov
- A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences 28 Vavilova str. Moscow 119991 Russia
- G.V. Plekhanov Russian University of Economics 36 Stremyanny Per. Moscow 117997 Russia
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de Souza Pinto Lemgruber R, Valgepea K, Gonzalez Garcia RA, de Bakker C, Palfreyman RW, Tappel R, Köpke M, Simpson SD, Nielsen LK, Marcellin E. A TetR-Family Protein (CAETHG_0459) Activates Transcription From a New Promoter Motif Associated With Essential Genes for Autotrophic Growth in Acetogens. Front Microbiol 2019; 10:2549. [PMID: 31803150 PMCID: PMC6873888 DOI: 10.3389/fmicb.2019.02549] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 10/22/2019] [Indexed: 01/08/2023] Open
Abstract
Acetogens can fix carbon (CO or CO2) into acetyl-CoA via the Wood-Ljungdahl pathway (WLP) that also makes them attractive cell factories for the production of fuels and chemicals from waste feedstocks. Although most biochemical details of the WLP are well understood and systems-level characterization of acetogen metabolism has recently improved, key transcriptional features such as promoter motifs and transcriptional regulators are still unknown in acetogens. Here, we use differential RNA-sequencing to identify a previously undescribed promoter motif associated with essential genes for autotrophic growth of the model-acetogen Clostridium autoethanogenum. RNA polymerase was shown to bind to the new promoter motif using a DNA-binding protein assay and proteomics enabled the discovery of four candidates to potentially function directly in control of transcription of the WLP and other key genes of C1 fixation metabolism. Next, in vivo experiments showed that a TetR-family transcriptional regulator (CAETHG_0459) and the housekeeping sigma factor (σA) activate expression of a reporter protein (GFP) in-frame with the new promoter motif from a fusion vector in Escherichia coli. Lastly, a protein-protein interaction assay with the RNA polymerase (RNAP) shows that CAETHG_0459 directly binds to the RNAP. Together, the data presented here advance the fundamental understanding of transcriptional regulation of C1 fixation in acetogens and provide a strategy for improving the performance of gas-fermenting bacteria by genetic engineering.
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Affiliation(s)
| | - Kaspar Valgepea
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
- ERA Chair in Gas Fermentation Technologies, Institute of Technology, University of Tartu, Tartu, Estonia
| | | | - Christopher de Bakker
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
| | - Robin William Palfreyman
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
- Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, QLD, Australia
| | | | | | | | - Lars Keld Nielsen
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
- Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, QLD, Australia
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49
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Clostridium sp. as Bio-Catalyst for Fuels and Chemicals Production in a Biorefinery Context. Catalysts 2019. [DOI: 10.3390/catal9110962] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Clostridium sp. is a genus of anaerobic bacteria capable of metabolizing several substrates (monoglycerides, diglycerides, glycerol, carbon monoxide, cellulose, and more), into valuable products. Biofuels, such as ethanol and butanol, and several chemicals, such as acetone, 1,3-propanediol, and butyric acid, can be produced by these organisms through fermentation processes. Among the most well-known species, Clostridium carboxidivorans, C. ragsdalei, and C. ljungdahlii can be highlighted for their ability to use gaseous feedstocks (as syngas), obtained from the gasification or pyrolysis of waste material, to produce ethanol and butanol. C. beijerinckii is an important species for the production of isopropanol and butanol, with the advantage of using hydrolysate lignocellulosic material, which is produced in large amounts by first-generation ethanol industries. High yields of 1,3 propanediol by C. butyricum are reported with the use of another by-product from fuel industries, glycerol. In this context, several Clostridium wild species are good candidates to be used as biocatalysts in biochemical or hybrid processes. In this review, literature data showing the technical viability of these processes are presented, evidencing the opportunity to investigate them in a biorefinery context.
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50
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Syngas-aided anaerobic fermentation for medium-chain carboxylate and alcohol production: the case for microbial communities. Appl Microbiol Biotechnol 2019; 103:8689-8709. [PMID: 31612269 DOI: 10.1007/s00253-019-10086-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 01/01/2023]
Abstract
Syngas fermentation has been successfully implemented in commercial-scale plants and can enable the biochemical conversion of the driest fractions of biomass through synthesis gas (H2, CO2, and CO). The process relies on optimized acetogenic strains able to reach and maintain high productivity of ethanol and acetate. In parallel, microbial communities have shown to be the best choice for the production of valuable medium-chain carboxylates through anaerobic fermentation of biomass, demanding low technical complexity and being able to realize simultaneous hydrolysis of the substrate. Each of the two technologies benefits from different strong points and has different challenges to overcome. This review discusses the rationales for merging these two seemingly disparate technologies by analyzing previous studies and drawing opinions based on the lessons learned from such studies. For keeping the technical demands of the resulting process low, a case is built for using microbial communities instead of pure strains. For that to occur, a shift from conventional syngas-based to "syngas-aided" anaerobic fermentation is suggested. Strategies for tackling the intricacies of working simultaneously with communities and syngas, such as competing pathways, and thermodynamic aspects are discussed as well as the stoichiometry and economic feasibility of the concept. Overall, syngas-aided anaerobic fermentation seems to be a promising concept for the biorefinery of the future. However, the effects of process parameters on microbial interactions have to be understood in greater detail, in order to achieve and sustain feasible medium-chain carboxylate and alcohol productivity.
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