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Böer T, Engelhardt L, Lüschen A, Eysell L, Yoshida H, Schneider D, Angenent LT, Basen M, Daniel R, Poehlein A. Isolation and characterization of novel acetogenic Moorella strains for employment as potential thermophilic biocatalysts. FEMS Microbiol Ecol 2024; 100:fiae109. [PMID: 39118367 PMCID: PMC11328732 DOI: 10.1093/femsec/fiae109] [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: 03/25/2024] [Revised: 06/05/2024] [Accepted: 08/07/2024] [Indexed: 08/10/2024] Open
Abstract
Thermophilic acetogenic bacteria have attracted attention as promising candidates for biotechnological applications such as syngas fermentation, microbial electrosynthesis, and methanol conversion. Here, we aimed to isolate and characterize novel thermophilic acetogens from diverse environments. Enrichment of heterotrophic and autotrophic acetogens was monitored by 16S rRNA gene-based bacterial community analysis. Seven novel Moorella strains were isolated and characterized by genomic and physiological analyses. Two Moorella humiferrea isolates showed considerable differences during autotrophic growth. The M. humiferrea LNE isolate (DSM 117358) fermented carbon monoxide (CO) to acetate, while the M. humiferrea OCP isolate (DSM 117359) transformed CO to hydrogen and carbon dioxide (H2 + CO2), employing the water-gas shift reaction. Another carboxydotrophic hydrogenogenic Moorella strain was isolated from the covering soil of an active charcoal burning pile and proposed as the type strain (ACPsT) of the novel species Moorella carbonis (DSM 116161T and CCOS 2103T). The remaining four novel strains were affiliated with Moorella thermoacetica and showed, together with the type strain DSM 2955T, the production of small amounts of ethanol from H2 + CO2 in addition to acetate. The physiological analyses of the novel Moorella strains revealed isolate-specific differences that considerably increase the knowledge base on thermophilic acetogens for future applications.
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Affiliation(s)
- Tim Böer
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Lisa Engelhardt
- Microbiology, Institute of Biological Sciences, University Rostock, 18059 Rostock, Germany
| | - Alina Lüschen
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Lena Eysell
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Hiroki Yoshida
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, 72074 Tübingen, Germany
| | - Dominik Schneider
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Largus T Angenent
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, 72074 Tübingen, Germany
| | - Mirko Basen
- Microbiology, Institute of Biological Sciences, University Rostock, 18059 Rostock, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, 37077 Göttingen, Germany
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Robazza A, Baleeiro FCF, Kleinsteuber S, Neumann A. Two-stage conversion of syngas and pyrolysis aqueous condensate into L-malate. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:85. [PMID: 38907325 PMCID: PMC11191387 DOI: 10.1186/s13068-024-02532-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
Hybrid thermochemical-biological processes have the potential to enhance the carbon and energy recovery from organic waste. This work aimed to assess the carbon and energy recovery potential of multifunctional processes to simultaneously sequestrate syngas and detoxify pyrolysis aqueous condensate (PAC) for short-chain carboxylates production. To evaluate relevant process parameters for mixed culture co-fermentation of syngas and PAC, two identical reactors were run under mesophilic (37 °C) and thermophilic (55 °C) conditions at increasing PAC loading rates. Both the mesophilic and the thermophilic process recovered at least 50% of the energy in syngas and PAC into short-chain carboxylates. During the mesophilic syngas and PAC co-fermentation, methanogenesis was completely inhibited while acetate, ethanol and butyrate were the primary metabolites. Over 90% of the amplicon sequencing variants based on 16S rRNA were assigned to Clostridium sensu stricto 12. During the thermophilic process, on the other hand, Symbiobacteriales, Syntrophaceticus, Thermoanaerobacterium, Methanothermobacter and Methanosarcina likely played crucial roles in aromatics degradation and methanogenesis, respectively, while Moorella thermoacetica and Methanothermobacter marburgensis were the predominant carboxydotrophs in the thermophilic process. High biomass concentrations were necessary to maintain stable process operations at high PAC loads. In a second-stage reactor, Aspergillus oryzae converted acetate, propionate and butyrate from the first stage into L-malate, confirming the successful detoxification of PAC below inhibitory levels. The highest L-malate yield was 0.26 ± 2.2 molL-malate/molcarboxylates recorded for effluent from the mesophilic process at a PAC load of 4% v/v. The results highlight the potential of multifunctional reactors where anaerobic mixed cultures perform simultaneously diverse process roles, such as carbon fixation, wastewater detoxification and carboxylates intermediate production. The recovered energy in the form of intermediate carboxylates allows for their use as substrates in subsequent fermentative stages.
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Affiliation(s)
- Alberto Robazza
- Institute of Process Engineering in Life Sciences 2: Electro Biotechnology, Karlsruhe Institute of Technology - KIT, 76131, Karlsruhe, Germany
| | - Flávio C F Baleeiro
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany
| | - Sabine Kleinsteuber
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany
| | - Anke Neumann
- Institute of Process Engineering in Life Sciences 2: Electro Biotechnology, Karlsruhe Institute of Technology - KIT, 76131, Karlsruhe, Germany.
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Kato J, Fujii T, Kato S, Wada K, Watanabe M, Nakamichi Y, Aoi Y, Morita T, Murakami K, Nakashimada Y. Genetic engineering of a thermophilic acetogen, Moorella thermoacetica Y72, to enable acetoin production. Front Bioeng Biotechnol 2024; 12:1398467. [PMID: 38812916 PMCID: PMC11133584 DOI: 10.3389/fbioe.2024.1398467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 04/29/2024] [Indexed: 05/31/2024] Open
Abstract
Acetogens are among the key microorganisms involved in the bioproduction of commodity chemicals from diverse carbon resources, such as biomass and waste gas. Thermophilic acetogens are particularly attractive because fermentation at higher temperatures offers multiple advantages. However, the main target product is acetic acid. Therefore, it is necessary to reshape metabolism using genetic engineering to produce the desired chemicals with varied carbon lengths. Although such metabolic engineering has been hampered by the difficulty involved in genetic modification, a model thermophilic acetogen, M. thermoacetica ATCC 39073, is the case with a few successful cases of C2 and C3 compound production, other than acetate. This brief report attempts to expand the product spectrum to include C4 compounds by using strain Y72 of Moorella thermoacetica. Strain Y72 is a strain related to the type strain ATCC 39073 and has been reported to have a less stringent restriction-modification system, which could alleviate the cumbersome transformation process. A simplified procedure successfully introduced a key enzyme for acetoin (a C4 chemical) production, and the resulting strains produced acetoin from sugars and gaseous substrates. The culture profile revealed varied acetoin yields depending on the type of substrate and culture conditions, implying the need for further engineering in the future. Thus, the use of a user-friendly chassis could benefit the genetic engineering of M. thermoacetica.
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Affiliation(s)
- Junya Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Hiroshima, Japan
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Hiroshima, Japan
| | - Tatsuya Fujii
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Hiroshima, Japan
| | - Setsu Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Hiroshima, Japan
| | - Keisuke Wada
- National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Masahiro Watanabe
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Hiroshima, Japan
| | - Yusuke Nakamichi
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Hiroshima, Japan
| | - Yoshiteru Aoi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Hiroshima, Japan
| | - Tomotake Morita
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Hiroshima, Japan
| | - Katsuji Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Hiroshima, Japan
| | - Yutaka Nakashimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Hiroshima, Japan
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Kato J, Matsuo T, Takemura K, Kato S, Fujii T, Wada K, Nakamichi Y, Watanabe M, Aoi Y, Morita T, Murakami K, Nakashimada Y. Isopropanol production via the thermophilic bioconversion of sugars and syngas using metabolically engineered Moorella thermoacetica. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:13. [PMID: 38281982 PMCID: PMC10823632 DOI: 10.1186/s13068-024-02460-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/11/2024] [Indexed: 01/30/2024]
Abstract
BACKGROUND Isopropanol (IPA) is a commodity chemical used as a solvent or raw material for polymeric products, such as plastics. Currently, IPA production depends largely on high-CO2-emission petrochemical methods that are not sustainable. Therefore, alternative low-CO2 emission methods are required. IPA bioproduction using biomass or waste gas is a promising method. RESULTS Moorella thermoacetica, a thermophilic acetogenic microorganism, was genetically engineered to produce IPA. A metabolic pathway related to acetone reduction was selected, and acetone conversion to IPA was achieved via the heterologous expression of secondary alcohol dehydrogenase (sadh) in the thermophilic bacterium. sadh-expressing strains were combined with acetone-producing strains, to obtain an IPA-producing strain. The strain produced IPA as a major product using hexose and pentose sugars as substrates (81% mol-IPA/mol-sugar). Furthermore, IPA was produced from CO, whereas acetate was an abundant byproduct. Fermentation using syngas containing both CO and H2 resulted in higher IPA production at the specific rate of 0.03 h-1. The supply of reducing power for acetone conversion from the gaseous substrates was examined by supplementing acetone to the culture, and the continuous and rapid conversion of acetone to IPA showed a sufficient supply of NADPH for Sadh. CONCLUSIONS The successful engineering of M. thermoacetica resulted in high IPA production from sugars. M. thermoacetica metabolism showed a high capacity for acetone conversion to IPA in the gaseous substrates, indicating acetone production as the bottleneck in IPA production for further improving the strain. This study provides a platform for IPA production via the metabolic engineering of thermophilic acetogens.
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Affiliation(s)
- Junya Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima, 739-8530, Japan
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Takeshi Matsuo
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima, 739-8530, Japan
| | - Kaisei Takemura
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima, 739-8530, Japan
| | - Setsu Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima, 739-8530, Japan
| | - Tatsuya Fujii
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Keisuke Wada
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Yusuke Nakamichi
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Masahiro Watanabe
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Yoshiteru Aoi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima, 739-8530, Japan
| | - Tomotake Morita
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Katsuji Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima, 739-0046, Japan
| | - Yutaka Nakashimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima, 739-8530, Japan.
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Moon J, Schubert A, Poehlein A, Daniel R, Müller V. A new metabolic trait in an acetogen: Mixed acid fermentation of fructose in a methylene-tetrahydrofolate reductase mutant of Acetobacterium woodii. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:339-351. [PMID: 37150590 PMCID: PMC10472528 DOI: 10.1111/1758-2229.13160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/20/2023] [Indexed: 05/09/2023]
Abstract
To inactivate the Wood-Ljungdahl pathway in the acetogenic model bacterium Acetobacterium woodii, the genes metVF encoding two of the subunits of the methylene-tetrahydrofolate reductase were deleted. As expected, the mutant did not grow on C1 compounds and also not on lactate, ethanol or butanediol. In contrast to a mutant in which the first enzyme of the pathway (hydrogen-dependent CO2 reductase) had been genetically deleted, cells were able to grow on fructose, albeit with lower rates and yields than the wild-type. Growth was restored by addition of an external electron sink, glycine betaine + CO2 or caffeate. Resting cells pre-grown on fructose plus an external electron acceptor fermented fructose to two acetate and four hydrogen, that is, performed hydrogenogenesis. Cells pre-grown under fermentative conditions on fructose alone redirected carbon and electrons to form lactate, formate, ethanol as well as hydrogen. Apparently, growth on fructose alone induced enzymes for mixed acid fermentation (MAF). Transcriptome analyses revealed enzymes potentially involved in MAF and a quantitative model for MAF from fructose in A. woodii is presented.
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Affiliation(s)
- Jimyung Moon
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular BiosciencesJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Anja Schubert
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular BiosciencesJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Anja Poehlein
- Göttingen Genomics Laboratory, Institute for Microbiology and GeneticsGeorg August UniversityGöttingenGermany
| | - Rolf Daniel
- Göttingen Genomics Laboratory, Institute for Microbiology and GeneticsGeorg August UniversityGöttingenGermany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular BiosciencesJohann Wolfgang Goethe UniversityFrankfurtGermany
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Neukirchen S, Pereira IAC, Sousa FL. Stepwise pathway for early evolutionary assembly of dissimilatory sulfite and sulfate reduction. THE ISME JOURNAL 2023; 17:1680-1692. [PMID: 37468676 PMCID: PMC10504309 DOI: 10.1038/s41396-023-01477-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/21/2023]
Abstract
Microbial dissimilatory sulfur metabolism utilizing dissimilatory sulfite reductases (Dsr) influenced the biochemical sulfur cycle during Earth's history and the Dsr pathway is thought to be an ancient metabolic process. Here we performed comparative genomics, phylogenetic, and synteny analyses of several Dsr proteins involved in or associated with the Dsr pathway across over 195,000 prokaryotic metagenomes. The results point to an archaeal origin of the minimal DsrABCMK(N) protein set, having as primordial function sulfite reduction. The acquisition of additional Dsr proteins (DsrJOPT) increased the Dsr pathway complexity. Archaeoglobus would originally possess the archaeal-type Dsr pathway and the archaeal DsrAB proteins were replaced with the bacterial reductive-type version, possibly at the same time as the acquisition of the QmoABC and DsrD proteins. Further inventions of two Qmo complex types, which are more spread than previously thought, allowed microorganisms to use sulfate as electron acceptor. The ability to use the Dsr pathway for sulfur oxidation evolved at least twice, with Chlorobi and Proteobacteria being extant descendants of these two independent adaptations.
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Affiliation(s)
- Sinje Neukirchen
- Genome Evolution and Ecology Group, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Inês A C Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Filipa L Sousa
- Genome Evolution and Ecology Group, Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
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Jia D, Deng W, Hu P, Jiang W, Gu Y. Thermophilic Moorella thermoacetica as a platform microorganism for C1 gas utilization: physiology, engineering, and applications. BIORESOUR BIOPROCESS 2023; 10:61. [PMID: 38647965 PMCID: PMC10992200 DOI: 10.1186/s40643-023-00682-z] [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: 06/27/2023] [Accepted: 08/29/2023] [Indexed: 04/25/2024] Open
Abstract
In the context of the rapid development of low-carbon economy, there has been increasing interest in utilizing naturally abundant and cost-effective one-carbon (C1) substrates for sustainable production of chemicals and fuels. Moorella thermoacetica, a model acetogenic bacterium, has attracted significant attention due to its ability to utilize carbon dioxide (CO2) and carbon monoxide (CO) via the Wood-Ljungdahl (WL) pathway, thereby showing great potential for the utilization of C1 gases. However, natural strains of M. thermoacetica are not yet fully suitable for industrial applications due to their limitations in carbon assimilation and conversion efficiency as well as limited product range. Over the past decade, progresses have been made in the development of genetic tools for M. thermoacetica, accelerating the understanding and modification of this acetogen. Here, we summarize the physiological and metabolic characteristics of M. thermoacetica and review the recent advances in engineering this bacterium. Finally, we propose the future directions for exploring the real potential of M. thermoacetica in industrial applications.
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Affiliation(s)
- Dechen Jia
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wangshuying Deng
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng Hu
- Shanghai GTLB Biotech Co., Ltd, 1688 North Guoquan Road, Shanghai, 200438, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
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Kim JY, Lee M, Oh S, Kang B, Yasin M, Chang IS. Acetogen and acetogenesis for biological syngas valorization. BIORESOURCE TECHNOLOGY 2023; 384:129368. [PMID: 37343794 DOI: 10.1016/j.biortech.2023.129368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 06/23/2023]
Abstract
The bioconversion of syngas using (homo)acetogens as biocatalysts shows promise as a viable option due to its higher selectivity and milder reaction conditions compared to thermochemical conversion. The current bioconversion process operates primarily to produce C2 chemicals (e.g., acetate and ethanol) with sufficient technology readiness levels (TRLs) in process engineering (as midstream) and product purification (as downstream). However, the economic feasibility of this process could be improved with greater biocatalytic options in the upstream phase. This review focuses on the Wood-Ljungdahl pathway (WLP) which is a biological syngas-utilization pathway, redox balance and ATP generation, suggesting that the use of a specific biocatalysts including Eubacterium limosum could be advantageous in syngas valorization. A pertinent strategy to mainly produce chemicals with a high degree of reduction is also provided with examples of flux control, mixed cultivation and mixotrophy. Finally, this article presents future direction of industrial utilization of syngas fermentation.
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Affiliation(s)
- Ji-Yeon Kim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Mungyu Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Soyoung Oh
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Byeongchan Kang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Muhammad Yasin
- Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Pakistan
| | - In Seop Chang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea.
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Takemura K, Kato J, Kato S, Fujii T, Wada K, Iwasaki Y, Aoi Y, Matsushika A, Morita T, Murakami K, Nakashimada Y. Enhancing acetone production from H 2 and CO 2 using supplemental electron acceptors in an engineered Moorella thermoacetica. J Biosci Bioeng 2023:S1389-1723(23)00112-3. [PMID: 37100649 DOI: 10.1016/j.jbiosc.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/08/2023] [Accepted: 04/02/2023] [Indexed: 04/28/2023]
Abstract
Acetogens grow autotrophically and use hydrogen (H2) as the energy source to fix carbon dioxide (CO2). This feature can be applied to gas fermentation, contributing to a circular economy. A challenge is the gain of cellular energy from H2 oxidation, which is substantially low, especially when acetate formation coupled with ATP production is diverted to other chemicals in engineered strains. Indeed, an engineered strain of the thermophilic acetogen Moorella thermoacetica that produces acetone lost autotrophic growth on H2 and CO2. We aimed to recover autotrophic growth and enhance acetone production, in which ATP production was assumed to be a limiting factor, by supplementing with electron acceptors. Among the four selected electron acceptors, thiosulfate and dimethyl sulfoxide (DMSO) enhanced both bacterial growth and acetone titers. DMSO was the most effective and was further analyzed. We showed that DMSO supplementation enhanced intracellular ATP levels, leading to increased acetone production. Although DMSO is an organic compound, it functions as an electron acceptor, not a carbon source. Thus, supplying electron acceptors is a potential strategy to complement the low ATP production caused by metabolic engineering and to improve chemical production from H2 and CO2.
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Affiliation(s)
- Kaisei Takemura
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Junya Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Setsu Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Tatsuya Fujii
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Keisuke Wada
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Yuki Iwasaki
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Yoshiteru Aoi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Akinori Matsushika
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan; National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Tomotake Morita
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Katsuji Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Yutaka Nakashimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan.
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Harahap BM, Ahring BK. Acetate Production from Syngas Produced from Lignocellulosic Biomass Materials along with Gaseous Fermentation of the Syngas: A Review. Microorganisms 2023; 11:microorganisms11040995. [PMID: 37110418 PMCID: PMC10143712 DOI: 10.3390/microorganisms11040995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/05/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Biotransformation of lignocellulose-derived synthetic gas (syngas) into acetic acid is a promising way of creating biochemicals from lignocellulosic waste materials. Acetic acid has a growing market with applications within food, plastics and for upgrading into a wide range of biofuels and bio-products. In this paper, we will review the microbial conversion of syngas to acetic acid. This will include the presentation of acetate-producing bacterial strains and their optimal fermentation conditions, such as pH, temperature, media composition, and syngas composition, to enhance acetate production. The influence of syngas impurities generated from lignocellulose gasification will further be covered along with the means to alleviate impurity problems through gas purification. The problem with mass transfer limitation of gaseous fermentation will further be discussed as well as ways to improve gas uptake during the fermentation.
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Affiliation(s)
- Budi Mandra Harahap
- Bioproducts, Science, and Engineering Laboratory, Washington State University Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA
- Department of Biological System Engineering, Washington State University, L. J. Smith Hall, Pullman, WA 99164, USA
| | - Birgitte K Ahring
- Bioproducts, Science, and Engineering Laboratory, Washington State University Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA
- Department of Biological System Engineering, Washington State University, L. J. Smith Hall, Pullman, WA 99164, USA
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Wegner Hall, Pullman, WA 99164, USA
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11
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Wang Z, Lin H, Zhang M, Yu W, Zhu C, Wang P, Huang Y, Lv F, Bai H, Wang S. Water-soluble conjugated polymers for bioelectronic systems. MATERIALS HORIZONS 2023; 10:1210-1233. [PMID: 36752220 DOI: 10.1039/d2mh01520j] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Bioelectronics is an interdisciplinary field of research that aims to establish a synergy between electronics and biology. Contributing to a deeper understanding of bioelectronic processes and the built bioelectronic systems, a variety of new phenomena, mechanisms and concepts have been derived in the field of biology, medicine, energy, artificial intelligence science, etc. Organic semiconductors can promote the applications of bioelectronics in improving original performance and creating new features for organisms due to their excellent photoelectric and electrical properties. Recently, water-soluble conjugated polymers (WSCPs) have been employed as a class of ideal interface materials to regulate bioelectronic processes between biological systems and electronic systems, relying on their satisfying ionic conductivity, water-solubility, good biocompatibility and the additional mechanical and electrical properties. In this review, we summarize the prominent contributions of WSCPs in the aspect of the regulation of bioelectronic processes and highlight the latest advances in WSCPs for bioelectronic applications, involving biosynthetic systems, photosynthetic systems, biophotovoltaic systems, and bioelectronic devices. The challenges and outlooks of WSCPs in designing high-performance bioelectronic systems are also discussed.
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Affiliation(s)
- Zenghao Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Hongrui Lin
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Miaomiao Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
| | - Wen Yu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Chuanwei Zhu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Pengcheng Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
| | - Yiming Huang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
| | - Fengting Lv
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
| | - Haotian Bai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
| | - Shu Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
- College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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12
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Isolation and Genomics of Futiania mangrovii gen. nov., sp. nov., a Rare and Metabolically Versatile Member in the Class Alphaproteobacteria. Microbiol Spectr 2023; 11:e0411022. [PMID: 36541777 PMCID: PMC9927469 DOI: 10.1128/spectrum.04110-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mangrove microorganisms are a major part of the coastal ecosystem and are directly associated with nutrient cycling. Despite their ecological significance, the collection of culturable mangrove microbes is limited due to difficulties in isolation and cultivation. Here, we report the isolation and genome sequence of strain FT118T, the first cultured representative of a previously uncultivated order UBA8317 within Alphaproteobacteria, based on the combined results of 16S rRNA gene similarity, phylogenomic, and average amino acid identity analyses. We propose Futianiales ord. nov. and Futianiaceae fam. nov. with Futiania as the type genus, and FT118T represents the type species with the name Futiania mangrovii gen. nov, sp. nov. The 16S rRNA gene sequence comparison reveals that this novel order is a rare member but has a ubiquitous distribution across various habitats worldwide, which is corroborated by the experimental confirmation that this isolate can physiologically adapt to a wide range of oxygen levels, temperatures, pH and salinity levels. Biochemical characterization, genomic annotation, and metatranscriptomic analysis of FT118T demonstrate that it is metabolically versatile and active in situ. Genomic analysis reveals adaptive features of Futianiales to fluctuating mangrove environments, including the presence of high- and low-affinity terminal oxidases, N-type ATPase, and the genomic capability of producing various compatible solutes and polyhydroxybutyrate, which possibly allow for the persistence of this novel order across various habitats. Collectively, these results expand the current culture collection of mangrove microorganisms, providing genomic insights of how this novel taxon adapts to fluctuating environments and the culture reference to unravel possible microbe-environment interactions. IMPORTANCE The rare biosphere constitutes an essential part of the microbial community and may drive nutrient cycling and other geochemical processes. However, the difficulty in microbial isolation and cultivation has hampered our understanding of the physiology and ecology of uncultured rare lineages. In this study, we successfully isolated a novel alphaproteobacterium, designated as FT118T, and performed a combination of phenotypic, phylogenetic, and phylogenomic analyses, confirming that this isolate represents the first cultured member of a previously uncultivated order UBA8317 within Alphaproteobacteria. It is a rare species with a ubiquitous distribution across different habitats. Genomic and metatranscriptomic analyses demonstrate that it is metabolically versatile and active in situ, suggesting its potential role in nutrient cycling despite being scarce. This work not only expands the current phylogeny of isolated Alphaproteobacteria but also provides genomic and culture reference to unravel microbial adaptation strategies in mangrove sediments and possible microbe-environment interactions.
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Kobayashi S, Kato J, Wada K, Takemura K, Kato S, Fujii T, Iwasaki Y, Aoi Y, Morita T, Matsushika A, Murakami K, Nakashimada Y. Reversible Hydrogenase Activity Confers Flexibility to Balance Intracellular Redox in Moorella thermoacetica. Front Microbiol 2022; 13:897066. [PMID: 35633713 PMCID: PMC9133594 DOI: 10.3389/fmicb.2022.897066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Hydrogen (H2) converted to reducing equivalents is used by acetogens to fix and metabolize carbon dioxide (CO2) to acetate. The utilization of H2 enables not only autotrophic growth, but also mixotrophic metabolism in acetogens, enhancing carbon utilization. This feature seems useful, especially when the carbon utilization efficiency of organic carbon sources is lowered by metabolic engineering to produce reduced chemicals, such as ethanol. The potential advantage was tested using engineered strains of Moorella thermoacetica that produce ethanol. By adding H2 to the fructose-supplied culture, the engineered strains produced increased levels of acetate, and a slight increase in ethanol was observed. The utilization of a knockout strain of the major acetate production pathway, aimed at increasing the carbon flux to ethanol, was unexpectedly hindered by H2-mediated growth inhibition in a dose-dependent manner. Metabolomic analysis showed a significant increase in intracellular NADH levels due to H2 in the ethanol-producing strain. Higher NADH level was shown to be the cause of growth inhibition because the decrease in NADH level by dimethyl sulfoxide (DMSO) reduction recovered the growth. When H2 was not supplemented, the intracellular NADH level was balanced by the reversible electron transfer from NADH oxidation to H2 production in the ethanol-producing strain. Therefore, reversible hydrogenase activity confers the ability and flexibility to balance the intracellular redox state of M. thermoacetica. Tuning of the redox balance is required in order to benefit from H2-supplemented mixotrophy, which was confirmed by engineering to produce acetone.
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Affiliation(s)
- Shunsuke Kobayashi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Junya Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Keisuke Wada
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Kaisei Takemura
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Setsu Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Tatsuya Fujii
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Yuki Iwasaki
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Yoshiteru Aoi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
| | - Tomotake Morita
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Akinori Matsushika
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Katsuji Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), Higashihiroshima, Japan
| | - Yutaka Nakashimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Japan
- *Correspondence: Yutaka Nakashimada,
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14
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Hu L, Guo S, Wang B, Fu R, Fan D, Jiang M, Fei Q, Gonzalez R. Bio-valorization of C1 gaseous substrates into bioalcohols: Potentials and challenges in reducing carbon emissions. Biotechnol Adv 2022; 59:107954. [DOI: 10.1016/j.biotechadv.2022.107954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 03/29/2022] [Accepted: 04/04/2022] [Indexed: 11/02/2022]
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15
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Abstract
The majority of the genes present in bacterial genomes remain poorly characterized, with up to one-third of those that are protein encoding having no definitive function. Transposon insertion sequencing represents a high-throughput technique that can help rectify this deficiency. The technology, however, can only be realistically applied to those species in which high rates of DNA transfer can be achieved. Here, we have developed a number of approaches that overcome this barrier in the autotrophic species Clostridium autoethanogenum by using a mariner-based transposon system. The inherent instability of such systems in the Escherichia coli conjugation donor due to transposition events was counteracted through the incorporation of a conditionally lethal codA marker on the plasmid backbone. Relatively low frequencies of transformation of the plasmid into C. autoethanogenum were circumvented through the use of a plasmid that is conditional for replication coupled with the routine implementation of an Illumina library preparation protocol that eliminates plasmid-based reads. A transposon library was then used to determine the essential genes needed for growth using carbon monoxide as the sole carbon and energy source. IMPORTANCE Although microbial genome sequences are relatively easily determined, assigning gene function remains a bottleneck. Consequently, relatively few genes are well characterized, leaving the function of many as either hypothetical or entirely unknown. High-throughput transposon sequencing can help remedy this deficiency, but is generally only applicable to microbes with efficient DNA transfer procedures. These exclude many microorganisms of importance to humankind either as agents of disease or as industrial process organisms. Here, we developed approaches to facilitate transposon insertion sequencing in the acetogen Clostridium autoethanogenum, a chassis being exploited to convert single-carbon waste gases CO and CO2 into chemicals and fuels at an industrial scale. This allowed the determination of gene essentiality under heterotrophic and autotrophic growth, providing insights into the utilization of CO as a sole carbon and energy source. The strategies implemented are translatable and will allow others to apply transposon insertion sequencing to other microbes where DNA transfer has until now represented a barrier to progress.
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16
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Rosenbaum FP, Poehlein A, Daniel R, Müller V. Energy‐conserving dimethyl sulfoxide reduction in the acetogenic bacterium
Moorella thermoacetica. Environ Microbiol 2022; 24:2000-2012. [DOI: 10.1111/1462-2920.15971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/02/2022] [Accepted: 03/07/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Florian P. Rosenbaum
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences Johann Wolfgang Goethe University Frankfurt Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics Georg‐August University Göttingen Göttingen 37077 Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics Georg‐August University Göttingen Göttingen 37077 Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences Johann Wolfgang Goethe University Frankfurt Germany
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17
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Hoyt KO, Woolston BM. Adapting isotopic tracer and metabolic flux analysis approaches to study C1 metabolism. Curr Opin Biotechnol 2022; 75:102695. [PMID: 35182834 DOI: 10.1016/j.copbio.2022.102695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 12/20/2022]
Abstract
Single-carbon (C1, or one-carbon) substrates are promising feedstocks for sustainable biofuel and biochemical production. Crucial to the goal of engineering C1-utilizing strains for improved production is a quantitative understanding of the organization, regulation and rates of the reactions that underpin C1 metabolism. 13C Metabolic flux analysis (MFA) is a well-established platform for interrogating these questions with multi-carbon substrates, and uses the differential labeling of metabolites that results from feeding a substrate with position-specific incorporation of 13C in order to infer quantitative fluxes and pathway topology. Adapting isotopic tracer approaches to C1 metabolism, where position-specific substrate labeling is impossible, requires additional experimental considerations. Here we review recent studies that have developed isotopic tracer approaches to overcome the challenge of uniform metabolite labeling and provide quantitative insight into C1 metabolism.
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Affiliation(s)
- Kathryn O Hoyt
- Department of Chemical Engineering, 201 Cullinane, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Benjamin M Woolston
- Department of Chemical Engineering, 201 Cullinane, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA.
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18
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Zhang Y, Pan X, Zuo J, Hu J. Production of n-caproate using food waste through thermophilic fermentation without addition of external electron donors. BIORESOURCE TECHNOLOGY 2022; 343:126144. [PMID: 34673194 DOI: 10.1016/j.biortech.2021.126144] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
The effectiveness of producing n-caproate from food waste without external electron donors (EDs) was investigated through batch and semi-continuous fermentation. The maximum concentration of n-caproate reached 10,226.28 mg COD/L during semi-continuous fermentation. The specificity for n-caproate was the highest at 40.19 ± 3.95%, and the soluble COD conversion rate of n-caproate reached up to 22.50 ± 1.09% at the end of batch fermentation. The production of n-caproate was coupled with the generation of lactate as an ED to facilitate chain elongation reactions. When lactate was used as the only substrate, n-butyrate (64.12 ± 20.11%) markedly dominated the products, instead of n-caproate (0.63 ± 0.07%). Microbial community analysis revealed that Caproiciproducens, Rummeliibacillus, and Clostridium_sensu_stricto_12 were the key genera related to n-caproate production. In addition to n-caproate, n-butyrate dominated the products in batch and semi-continuous fermentation with a maximum specificity of 47.59 ± 3.39%. Clostridium_sensu_stricto_7 was committed to producing n-butyrate from lactate.
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Affiliation(s)
- Yanyan Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xinrong Pan
- College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, China
| | - Jiane Zuo
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China.
| | - Jiamin Hu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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Biological conversion of carbon monoxide and hydrogen by anaerobic culture: Prospect of anaerobic digestion and thermochemical processes combination. Biotechnol Adv 2021; 58:107886. [PMID: 34915147 DOI: 10.1016/j.biotechadv.2021.107886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/26/2021] [Accepted: 12/08/2021] [Indexed: 01/04/2023]
Abstract
Waste biomass is considered a promising renewable energy feedstock that can be converted by anaerobic digestion. However, anaerobic digestion application can be challenging due to the structural complexity of several waste biomass kinds. Therefore, coupling anaerobic digestion with thermochemical processes can offset the limitations and convert the hardly biodegradable waste biomass, including digestate residue, into value-added products: syngas and pyrogas (gaseous mixtures consisting mainly of H2, CO, CO2), bio-oil, and biochar for further valorisation. In this review, the utilisation boundaries and benefits of the aforementioned products by anaerobic culture are discussed. First, thermochemical process parameters for an enhanced yield of desired products are summarised. Particularly, the microbiology of CO and H2 mixture biomethanation and fermentation in anaerobic digestion is presented. Finally, the state-of-the-art biological conversion of syngas and pyrogas to CH4 mediated by anaerobic culture is adequately described. Extensive research shows the successful selective biological conversion of CO and H2 to CH4, acetic acid, and alcohols. The main bottleneck is the gas-liquid mass transfer which can be enhanced appropriately by bioreactors' configurations. A few research groups focus on bio-oil and biochar addition into anaerobic digesters. However, according to the literature review, there has been no research for utilising all value-added products at once in anaerobic digestion published so far. Although synergic effects of such can be expected. In summary, the combination of anaerobic digestion and thermochemical processes is a promising alternative for wide-scale waste biomass utilisation in practice.
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20
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Jiao JY, Fu L, Hua ZS, Liu L, Salam N, Liu PF, Lv AP, Wu G, Xian WD, Zhu Q, Zhou EM, Fang BZ, Oren A, Hedlund BP, Jiang HC, Knight R, Cheng L, Li WJ. Insight into the function and evolution of the Wood-Ljungdahl pathway in Actinobacteria. THE ISME JOURNAL 2021; 15:3005-3018. [PMID: 33953361 PMCID: PMC8443620 DOI: 10.1038/s41396-021-00935-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/07/2021] [Accepted: 02/10/2021] [Indexed: 02/03/2023]
Abstract
Carbon fixation by chemoautotrophic microbes such as homoacetogens had a major impact on the transition from the inorganic to the organic world. Recent reports have shown the presence of genes for key enzymes associated with the Wood-Ljungdahl pathway (WLP) in the phylum Actinobacteria, which adds to the diversity of potential autotrophs. Here, we compiled 42 actinobacterial metagenome-assembled genomes (MAGs) from new and existing metagenomic datasets and propose three novel classes, Ca. Aquicultoria, Ca. Geothermincolia and Ca. Humimicrobiia. Most members of these classes contain genes coding for acetogenesis through the WLP, as well as a variety of hydrogenases (NiFe groups 1a and 3b-3d; FeFe group C; NiFe group 4-related hydrogenases). We show that the three classes acquired the hydrogenases independently, yet the carbon monoxide dehydrogenase/acetyl-CoA synthase complex (CODH/ACS) was apparently present in their last common ancestor and was inherited vertically. Furthermore, the Actinobacteria likely donated genes for CODH/ACS to multiple lineages within Nitrospirae, Deltaproteobacteria (Desulfobacterota), and Thermodesulfobacteria through multiple horizontal gene transfer events. Finally, we show the apparent growth of Ca. Geothermincolia and H2-dependent acetate production in hot spring enrichment cultures with or without the methanogenesis inhibitor 2-bromoethanesulfonate, which is consistent with the proposed homoacetogenic metabolism.
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Affiliation(s)
- Jian-Yu Jiao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Li Fu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Areas, Chengdu, PR China
| | - Zheng-Shuang Hua
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, PR China
| | - Lan Liu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Nimaichand Salam
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Peng-Fei Liu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Areas, Chengdu, PR China
| | - Ai-Ping Lv
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Geng Wu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, PR China
| | - Wen-Dong Xian
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Qiyun Zhu
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
| | - En-Min Zhou
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Bao-Zhu Fang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, PR China
| | - Aharon Oren
- The Alexander Silberman Institute of Life Sciences, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, USA
- Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Hong-Chen Jiang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, PR China
| | - Rob Knight
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, USA
| | - Lei Cheng
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Areas, Chengdu, PR China.
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China.
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, PR China.
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21
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Liu C, Ren L, Yan B, Luo L, Zhang J, Awasthi MK. Electron transfer and mechanism of energy production among syntrophic bacteria during acidogenic fermentation: A review. BIORESOURCE TECHNOLOGY 2021; 323:124637. [PMID: 33421831 DOI: 10.1016/j.biortech.2020.124637] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/25/2020] [Accepted: 12/26/2020] [Indexed: 06/12/2023]
Abstract
Volatile fatty acids (VFAs) production plays an important role in the process of anaerobic digestion (AD), which is often the critical factor determining the metabolic pathways and energy recovery efficiency. Fermenting bacteria and acetogenic bacteria are in syntrophic relations during AD. Thus, clear elucidation of the interspecies electron transfer and energetic mechanisms among syntrophic bacteria is essential for optimization of acidogenic. This review aims to discuss the electron transfer and energetic mechanism in syntrophic processes between fermenting bacteria and acetogenic bacteria during VFAs production. Homoacetogenesis also plays a role in the syntrophic system by converting H2 and CO2 to acetate. Potential applications of these syntrophic activities in bioelectrochemical system and value-added product recovery from AD of organic wastes are also discussed. The study of acidogenic syntrophic relations is in its early stages, and additional investigation is required to better understand the mechanism of syntrophic relations.
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Affiliation(s)
- Chao Liu
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China
| | - Liheng Ren
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China
| | - Binghua Yan
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China
| | - Lin Luo
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China
| | - Jiachao Zhang
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Swedish Centre for Resource Recovery, University of Borås, 50190 Borås, Sweden.
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22
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Göbbels L, Poehlein A, Dumnitch A, Egelkamp R, Kröger C, Haerdter J, Hackl T, Feld A, Weller H, Daniel R, Streit WR, Schoelmerich MC. Cysteine: an overlooked energy and carbon source. Sci Rep 2021; 11:2139. [PMID: 33495538 PMCID: PMC7835215 DOI: 10.1038/s41598-021-81103-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/31/2020] [Indexed: 11/09/2022] Open
Abstract
Biohybrids composed of microorganisms and nanoparticles have emerged as potential systems for bioenergy and high-value compound production from CO2 and light energy, yet the cellular and metabolic processes within the biological component of this system are still elusive. Here we dissect the biohybrid composed of the anaerobic acetogenic bacterium Moorella thermoacetica and cadmium sulphide nanoparticles (CdS) in terms of physiology, metabolism, enzymatics and transcriptomic profiling. Our analyses show that while the organism does not grow on l-cysteine, it is metabolized to acetate in the biohybrid system and this metabolism is independent of CdS or light. CdS cells have higher metabolic activity, despite an inhibitory effect of Cd2+ on key enzymes, because of an intracellular storage compound linked to arginine metabolism. We identify different routes how cysteine and its oxidized form can be innately metabolized by the model acetogen and what intracellular mechanisms are triggered by cysteine, cadmium or blue light.
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Affiliation(s)
- Luise Göbbels
- Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, University of Hamburg, 22609, Hamburg, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstraße 8, 37077, Göttingen, Germany
| | - Albert Dumnitch
- Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, University of Hamburg, 22609, Hamburg, Germany
| | - Richard Egelkamp
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstraße 8, 37077, Göttingen, Germany
| | - Cathrin Kröger
- Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, University of Hamburg, 22609, Hamburg, Germany
| | - Johanna Haerdter
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Thomas Hackl
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Artur Feld
- Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Horst Weller
- Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Georg-August University Göttingen, Grisebachstraße 8, 37077, Göttingen, Germany
| | - Wolfgang R Streit
- Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, University of Hamburg, 22609, Hamburg, Germany
| | - Marie Charlotte Schoelmerich
- Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, University of Hamburg, 22609, Hamburg, Germany.
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23
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Hidalgo-Ulloa A, Sánchez-Andrea I, Buisman C, Weijma J. Sulfur Reduction at Hyperthermoacidophilic Conditions with Mesophilic Anaerobic Sludge as the Inoculum. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14656-14663. [PMID: 33136376 PMCID: PMC7676295 DOI: 10.1021/acs.est.0c02557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Sulfur reduction at hyperthermoacidophilic conditions represents a promising opportunity for metal sulfide precipitation from hot acidic metallurgical streams, avoiding costly cooling down. The suitability of mesophilic anaerobic sludges as the inoculum for sulfur-reducing bioreactors operated at high temperature and low pH was explored. We examined sludges from full-scale anaerobic reactors for sulfur-reducing activity at pH 2.0-3.5 and 70 or 80 °C, with H2 as an electron donor. At pH 3.5 in batch experiments, sulfidogenesis started within 4 days, reaching up to 100-200 mg·L-1 of dissolved sulfide produced after 19-24 days, depending on the origin of the sludge. Sulfidogenesis resumed after removing H2S by flushing with nitrogen gas, indicating that sulfide was limiting the conversion. The best performing sludge was used to inoculate a 4 L gas-lift reactor fed with H2 as the electron donor, CO2 as the carbon source, and elemental sulfur as the electron acceptor. The reactor was operated in semibatch mode at a pH 3.5 and 80 °C, and stable sulfide production rates of 60-80 mg·L-1·d-1 were achieved for a period of 24 days, without formation of methane or acetate. Our results reveal the potential of mesophilic anaerobic sludges as seed material for sulfur-reducing bioprocesses operated at hyperthermoacidophilic conditions. The process needs further optimization of the volumetric sulfide production rate to gain relevance for practice.
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Affiliation(s)
- Adrian Hidalgo-Ulloa
- Department
of Environmental Technology, Wageningen
University & Research, Wageningen 6708 WG, the Netherlands
| | - Irene Sánchez-Andrea
- Laboratory
of Microbiology, Wageningen University &
Research, Wageningen 6708 WE, the Netherlands
| | - Cees Buisman
- Department
of Environmental Technology, Wageningen
University & Research, Wageningen 6708 WG, the Netherlands
| | - Jan Weijma
- Department
of Environmental Technology, Wageningen
University & Research, Wageningen 6708 WG, the Netherlands
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24
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Vees CA, Neuendorf CS, Pflügl S. Towards continuous industrial bioprocessing with solventogenic and acetogenic clostridia: challenges, progress and perspectives. J Ind Microbiol Biotechnol 2020; 47:753-787. [PMID: 32894379 PMCID: PMC7658081 DOI: 10.1007/s10295-020-02296-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022]
Abstract
The sustainable production of solvents from above ground carbon is highly desired. Several clostridia naturally produce solvents and use a variety of renewable and waste-derived substrates such as lignocellulosic biomass and gas mixtures containing H2/CO2 or CO. To enable economically viable production of solvents and biofuels such as ethanol and butanol, the high productivity of continuous bioprocesses is needed. While the first industrial-scale gas fermentation facility operates continuously, the acetone-butanol-ethanol (ABE) fermentation is traditionally operated in batch mode. This review highlights the benefits of continuous bioprocessing for solvent production and underlines the progress made towards its establishment. Based on metabolic capabilities of solvent producing clostridia, we discuss recent advances in systems-level understanding and genome engineering. On the process side, we focus on innovative fermentation methods and integrated product recovery to overcome the limitations of the classical one-stage chemostat and give an overview of the current industrial bioproduction of solvents.
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Affiliation(s)
- Charlotte Anne Vees
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria
| | - Christian Simon Neuendorf
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria
| | - Stefan Pflügl
- Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria
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25
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Sorokin DY, Diender M, Merkel AY, Koenen M, Bale NJ, Pabst M, Sinninghe Damsté JS, Sousa DZ. Natranaerofaba carboxydovora gen. nov., sp. nov., an extremely haloalkaliphilic CO-utilizing acetogen from a hypersaline soda lake representing a novel deep phylogenetic lineage in the class 'Natranaerobiia'. Environ Microbiol 2020; 23:3460-3476. [PMID: 32955149 PMCID: PMC8359318 DOI: 10.1111/1462-2920.15241] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 01/02/2023]
Abstract
An anaerobic enrichment with CO from sediments of hypersaline soda lakes resulted in a methane‐forming binary culture, whereby CO was utilized by a bacterium and not the methanogenic partner. The bacterial isolate ANCO1 forms a deep‐branching phylogenetic lineage at the level of a new family within the class ‘Natranaerobiia’. It is an extreme haloalkaliphilic and moderate thermophilic acetogen utilizing CO, formate, pyruvate and lactate as electron donors and thiosulfate, nitrate (reduced to ammonia) and fumarate as electron acceptors. The genome of ANCO1 encodes a full Wood–Ljungdahl pathway allowing for CO oxidation and acetogenic conversion of pyruvate. A locus encoding Nap nitrate reductase/NrfA ammonifying nitrite reductase is also present. Thiosulfate respiration is encoded by a Phs/Psr‐like operon. The organism obviously relies on Na‐based bioenergetics, since the genome encodes for the Na+‐Rnf complex, Na+‐F1F0 ATPase and Na+‐translocating decarboxylase. Glycine betaine serves as a compatible solute. ANCO1 has an unusual membrane polar lipid composition dominated by diethers, more common among archaea, probably a result of adaptation to multiple extremophilic conditions. Overall, ANCO1 represents a unique example of a triple extremophilic CO‐oxidizing anaerobe and is classified as a novel genus and species Natranaerofaba carboxydovora in a novel family Natranaerofabacea.
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Affiliation(s)
- Dimitry Y Sorokin
- Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia.,Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Martijn Diender
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Alexander Y Merkel
- Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Michel Koenen
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Den Burg, The Netherlands
| | - Nicole J Bale
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Den Burg, The Netherlands
| | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Jaap S Sinninghe Damsté
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Den Burg, The Netherlands.,Department of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
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26
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Abstract
Microbial CO2 fixation and conversion constitute a potential solution to both utilization of greenhouse gas or industrial waste gases and sustainable production of bulk chemicals and fuels. Autotrophic gas-fermenting bacteria play central roles in this bioprocess. This study provides new insights regarding the metabolic regulatory mechanisms underlying CO2 reduction in Clostridium ljungdahlii, a representative gas-fermenting bacterium. A critical formate dehydrogenase (FDH1) responsible for fixing CO2 and a dominant reversible lysine acetylation system, At2/Dat1, were identified. Furthermore, FDH1 was found to be interactively regulated by both the At2/Dat1 system and the global transcriptional factor CcpA, and the two regulatory systems are mutually restricted. Reconstruction of this multilevel metabolic regulatory module led to improved CO2 metabolism by C. ljungdahlii. These findings not only substantively expand our understanding but also provide a potentially useful metabolic engineering strategy for microbial carbon fixation. Protein lysine acetylation, a prevalent posttranslational modification, regulates numerous crucial biological processes in cells. Nevertheless, how lysine acetylation interacts with other types of regulation to coordinate metabolism remains largely unknown owing to the complexity of the process. Here, using a representative gas-fermenting bacterium, Clostridium ljungdahlii, we revealed a novel regulatory mechanism that employs both the lysine acetylation and transcriptional regulation systems to interactively control CO2 fixation, a key biological process for utilizing this one-carbon gas. A dominant lysine acetyltransferase/deacetylase system, At2/Dat1, was identified and found to regulate FDH1 (formate dehydrogenase responsible for CO2 fixation) activity via a crucial acetylation site (lysine-29). Notably, the global transcription factor CcpA was also shown to be regulated by At2/Dat1; in turn, CcpA could directly control At2 expression, thus indicating an unreported interaction mode between the acetylation system and transcription factors. Moreover, CcpA was observed to negatively regulate FDH1 expression, which, when combined with At2/Dat1, leads to the collaborative regulation of this enzyme. Based on this concept, we reconstructed the regulatory network related to FDH1, realizing significantly increased CO2 utilization by C. ljungdahlii.
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27
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Inoue M, Izumihara H, Fukuyama Y, Omae K, Yoshida T, Sako Y. Carbon monoxide-dependent transcriptional changes in a thermophilic, carbon monoxide-utilizing, hydrogen-evolving bacterium Calderihabitans maritimus KKC1 revealed by transcriptomic analysis. Extremophiles 2020; 24:551-564. [PMID: 32388815 PMCID: PMC7306483 DOI: 10.1007/s00792-020-01175-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/27/2020] [Indexed: 11/30/2022]
Abstract
Calderihabitans maritimus KKC1 is a thermophilic, carbon monoxide (CO)-utilizing, hydrogen-evolving bacterium that harbors seven cooS genes for anaerobic CO dehydrogenases and six hyd genes for [NiFe] hydrogenases and capable of using a variety of electron acceptors coupled to CO oxidation. To understand the relationships among these unique features and the transcriptional adaptation of the organism to CO, we performed a transcriptome analysis of C. maritimus KKC1 grown under 100% CO and N2 conditions. Of its 3114 genes, 58 and 32 genes were significantly upregulated and downregulated in the presence of CO, respectively. A cooS–ech gene cluster, an “orphan” cooS gene, and bidirectional hyd genes were upregulated under CO, whereas hydrogen-uptake hyd genes were downregulated. Transcriptional changes in anaerobic respiratory genes supported the broad usage of electron acceptors in C. maritimus KKC1 under CO metabolism. Overall, the majority of the differentially expressed genes were oxidoreductase-like genes, suggesting metabolic adaptation to the cellular redox change upon CO oxidation. Moreover, our results suggest a transcriptional response mechanism to CO that involves multiple transcription factors, as well as a CO-responsive transcriptional activator (CooA). Our findings shed light on the diverse mechanisms for transcriptional and metabolic adaptations to CO in CO-utilizing and hydrogen-evolving bacteria.
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Affiliation(s)
- Masao Inoue
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Hikaru Izumihara
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yuto Fukuyama
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Kimiho Omae
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Takashi Yoshida
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yoshihiko Sako
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
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28
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29
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Müller V. New Horizons in Acetogenic Conversion of One-Carbon Substrates and Biological Hydrogen Storage. Trends Biotechnol 2019; 37:1344-1354. [DOI: 10.1016/j.tibtech.2019.05.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/17/2019] [Accepted: 05/23/2019] [Indexed: 01/12/2023]
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30
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Schoelmerich MC, Müller V. Energy-converting hydrogenases: the link between H 2 metabolism and energy conservation. Cell Mol Life Sci 2019; 77:1461-1481. [PMID: 31630229 DOI: 10.1007/s00018-019-03329-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/17/2019] [Accepted: 10/01/2019] [Indexed: 10/25/2022]
Abstract
The reversible interconversion of molecular hydrogen and protons is one of the most ancient microbial metabolic reactions and catalyzed by hydrogenases. A widespread yet largely enigmatic group comprises multisubunit [NiFe] hydrogenases, that directly couple H2 metabolism to the electrochemical ion gradient across the membranes of bacteria and of archaea. These complexes are collectively referred to as energy-converting hydrogenases (Ech), as they reversibly transform redox energy into physicochemical energy. Redox energy is typically provided by a low potential electron donor such as reduced ferredoxin to fuel H2 evolution and the establishment of a transmembrane electrochemical ion gradient ([Formula: see text]). The [Formula: see text] is then utilized by an ATP synthase for energy conservation by generating ATP. This review describes the modular structure/function of Ech complexes, focuses on insights into the energy-converting mechanisms, describes the evolutionary context and delves into the implications of relying on an Ech complex as respiratory enzyme for microbial metabolism.
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Affiliation(s)
- Marie Charlotte Schoelmerich
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.,Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, Universität Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany
| | - Volker Müller
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.
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31
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Emerson DF, Stephanopoulos G. Limitations in converting waste gases to fuels and chemicals. Curr Opin Biotechnol 2019; 59:39-45. [DOI: 10.1016/j.copbio.2019.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 01/29/2019] [Accepted: 02/04/2019] [Indexed: 12/22/2022]
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32
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Keller A, Schink B, Müller N. Alternative Pathways of Acetogenic Ethanol and Methanol Degradation in the Thermophilic Anaerobe Thermacetogenium phaeum. Front Microbiol 2019; 10:423. [PMID: 30949135 PMCID: PMC6436200 DOI: 10.3389/fmicb.2019.00423] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/18/2019] [Indexed: 11/26/2022] Open
Abstract
Growth of the anaerobic thermophile Thermacetogenium phaeum with methanol, ethanol, ethanolamine, and acetate was investigated in axenic cultures and in syntrophic cultures with Methanothermobacter thermautotrophicus. Microcompartment genes were identified in the T. phaeum genome, and presence of microcompartments was confirmed by transmission electron microscopy and proteome analysis. These genes were expressed only during growth with ethanolamine. Proteome data were compared after growth with all four substrates, and activities of key enzymes of the Wood–Ljungdahl pathway and of enzyme systems leading to production or degradation of acetaldehyde such as alcohol dehydrogenase, aldehyde:ferredoxin oxidoreductase, acetate kinase, and phosphate acetyltransferase were measured in cytoplasmic fractions. Accounting of fermentation stoichiometries and growth yields with all four substrates showed that ethanol and methanol oxidation follow the same stoichiometries as in Acetobacterium woodii. On the other hand, the pathways of ethanol and methanol degradations vary between both organisms. Growth yields of T. phaeum were substantially lower than reported for A. woodii. Since T. phaeum has no Rnf complex encoded in its genome, the mechanisms of ATP synthesis have to be different from those of A. woodii. In addition to the central degradation pathways also found in A. woodii, T. phaeum maintains enzyme systems that compensate for the absence of an Rnf-complex but which on the other hand cause a loss of energy. On the basis of our data, pathways of methanol and ethanol degradation in T. phaeum are discussed.
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Affiliation(s)
- Anja Keller
- Department of Biology, Universität Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology, Konstanz, Germany
| | - Bernhard Schink
- Department of Biology, Universität Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology, Konstanz, Germany
| | - Nicolai Müller
- Department of Biology, Universität Konstanz, Konstanz, Germany
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33
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Emerson DF, Woolston BM, Liu N, Donnelly M, Currie DH, Stephanopoulos G. Enhancing hydrogen-dependent growth of and carbon dioxide fixation by Clostridium ljungdahlii through nitrate supplementation. Biotechnol Bioeng 2018; 116:294-306. [PMID: 30267586 DOI: 10.1002/bit.26847] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/23/2018] [Accepted: 09/28/2018] [Indexed: 12/15/2022]
Abstract
Synthesis gas (syngas) fermentation via the Wood-Ljungdahl pathway is receiving growing attention as a possible platform for the fixation of CO 2 and renewable production of fuels and chemicals. However, the pathway operates near the thermodynamic limit of life, resulting in minimal adenosine triphosphate (ATP) production and long doubling times. This calls into question the feasibility of producing high-energy compounds at industrially relevant levels. In this study, we investigated the possibility of co-utilizing nitrate as an inexpensive additional electron acceptor to enhance ATP production during H 2 -dependent growth of Clostridium ljungdahlii, Moorella thermoacetica, and Acetobacterium woodii. In contrast to other acetogens tested, growth rate and final biomass titer were improved for C. ljungdahlii growing on a mixture of H 2 and CO 2 when supplemented with nitrate. Transcriptomic analysis, 13 CO 2 labeling, and an electron balance were used to understand how electron flux was partitioned between CO 2 and nitrate. We further show that, with nitrate supplementation, the ATP/adenosine diphosphate (ADP) ratio and acetyl-CoA pools were increased by fivefold and threefold, respectively, suggesting that this strategy could be useful for the production of ATP-intensive heterologous products from acetyl-CoA. Finally, we propose a pathway for enhanced ATP production from nitrate and use this as a basis to calculate theoretical yields for a variety of products. This study demonstrates a viable strategy for the decoupling of ATP production from carbon dioxide fixation, which will serve to significantly improve the CO 2 fixation rate and the production metrics of other chemicals from CO 2 and H 2 in this host.
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Affiliation(s)
- David F Emerson
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Benjamin M Woolston
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Nian Liu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Mackenzie Donnelly
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Devin H Currie
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Gregory Stephanopoulos
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
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34
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Burton R, Can M, Esckilsen D, Wiley S, Ragsdale SW. Production and properties of enzymes that activate and produce carbon monoxide. Methods Enzymol 2018; 613:297-324. [PMID: 30509471 PMCID: PMC6309614 DOI: 10.1016/bs.mie.2018.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The chapter focuses on the methods involved in producing and characterizing two key nickel-iron-sulfur enzymes in the Wood-Ljungdahl pathway (WLP) of anaerobic conversion of carbon dioxide fixation into acetyl-CoA: carbon monoxide dehydrogenase (CODH) and acetyl-CoA synthase (ACS). The WLP is used for biosynthesis of cell material and energy conservation by anaerobic bacteria and archaea, and it is central to several industrial biotechnology processes aimed at using syngas and waste gases for the production of fuels and chemicals. The pathway can run in reverse to allow organisms, e. g., methanogens and sulfate reducers, to grow on acetate. The CODH and ACS intertwine to form a tenacious CODH/ACS complex that converts CO2, a methyl group, and coenzyme A into acetyl-CoA. CODH also behaves as a modular unit that can function as an independent homodimer. Besides coupling to ACS, CODH can interact with hydrogenases to couple CO oxidation to H2 formation. These enzymes have been purified and characterized from several microbes.
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Affiliation(s)
- Rodney Burton
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Mehmet Can
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Daniel Esckilsen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Seth Wiley
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Stephen W Ragsdale
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, United States.
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35
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Pilizota T, Yang YT. "Do It Yourself" Microbial Cultivation Techniques for Synthetic and Systems Biology: Cheap, Fun, and Flexible. Front Microbiol 2018; 9:1666. [PMID: 30105008 PMCID: PMC6077191 DOI: 10.3389/fmicb.2018.01666] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/04/2018] [Indexed: 12/14/2022] Open
Abstract
With the emergence of inexpensive 3D printing technology, open-source platforms for electronic prototyping and single-board computers, "Do it Yourself" (DIY) approaches to the cultivation of microbial cultures are becoming more feasible, user-friendly, and thus wider spread. In this perspective, we survey some of these approaches, as well as add-on solutions to commercial instruments for synthetic and system biology applications. We discuss different cultivation designs, including capabilities and limitations. Our intention is to encourage the reader to consider the DIY solutions. Overall, custom cultivation devices offer controlled growth environments with in-line monitoring of, for example, optical density, fluorescence, pH, and dissolved oxygen, all at affordable prices. Moreover, they offer a great degree of flexibility for different applications and requirements and are fun to design and construct. We include several illustrative examples, such as gaining optogenetic control and adaptive laboratory evolution experiments.
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Affiliation(s)
- Teuta Pilizota
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ya-Tang Yang
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
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36
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Zhao J, Wang D, Liu Y, Ngo HH, Guo W, Yang Q, Li X. Novel stepwise pH control strategy to improve short chain fatty acid production from sludge anaerobic fermentation. BIORESOURCE TECHNOLOGY 2018; 249:431-438. [PMID: 29065325 DOI: 10.1016/j.biortech.2017.10.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 05/28/2023]
Abstract
This study reports an innovative strategy known as stepwise pH fermentation, developed to enhance the production of short chain volatile fatty acids (SCFA) from waste activated sludge (WAS) anaerobic fermentation. Experimental results confirmed the optimal pH for WAS disruption and acidification was 11 and 9, respectively, and corresponding optimal time was, respectively, 5 d and 2 d. In this scenario, the optimal SCFA yield was 2356 mg chemical oxygen demand (COD)/L, which was much higher than that derived from alkaline fermentation system. Investigation of the mechanism indicated that pH 11 could accelerate the disruption of WAS and inhibit the activities of methanogens; furthermore, pH 9 was beneficial to the activity of acid-producing bacteria, resulting in more SCFA production. Stepwise pH fermentation integrated with sodium chloride (NaCl) present in WAS had synergistic impacts on WAS anaerobic fermentation.
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Affiliation(s)
- Jianwei Zhao
- Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia; Department of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Yiwen Liu
- Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia; Department of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Huu Hao Ngo
- Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia; Department of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China.
| | - Wenshan Guo
- Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia; Department of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Qi Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Xiaoming Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
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Nangle SN, Sakimoto KK, Silver PA, Nocera DG. Biological-inorganic hybrid systems as a generalized platform for chemical production. Curr Opin Chem Biol 2017; 41:107-113. [DOI: 10.1016/j.cbpa.2017.10.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 10/16/2017] [Accepted: 10/20/2017] [Indexed: 12/16/2022]
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Genomic Analysis of Calderihabitans maritimus KKC1, a Thermophilic, Hydrogenogenic, Carboxydotrophic Bacterium Isolated from Marine Sediment. Appl Environ Microbiol 2017; 83:AEM.00832-17. [PMID: 28526793 DOI: 10.1128/aem.00832-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 05/13/2017] [Indexed: 11/20/2022] Open
Abstract
Calderihabitans maritimus KKC1 is a thermophilic, hydrogenogenic carboxydotroph isolated from a submerged marine caldera. Here, we describe the de novo sequencing and feature analysis of the C. maritimus KKC1 genome. Genome-based phylogenetic analysis confirmed that C. maritimus KKC1 was most closely related to the genus Moorella, which includes well-studied acetogenic members. Comparative genomic analysis revealed that, like Moorella, C. maritimus KKC1 retained both the CO2-reducing Wood-Ljungdahl pathway and energy-converting hydrogenase-based module activated by reduced ferredoxin, but it lacked the HydABC and NfnAB electron-bifurcating enzymes and pyruvate:ferredoxin oxidoreductase required for ferredoxin reduction for acetogenic growth. Furthermore, C. maritimus KKC1 harbored six genes encoding CooS, a catalytic subunit of the anaerobic CO dehydrogenase that can reduce ferredoxin via CO oxidation, whereas Moorella possessed only two CooS genes. Our analysis revealed that three cooS genes formed known gene clusters in other microorganisms, i.e., cooS-acetyl coenzyme A (acetyl-CoA) synthase (which contained a frameshift mutation), cooS-energy-converting hydrogenase, and cooF-cooS-FAD-NAD oxidoreductase, while the other three had novel genomic contexts. Sequence composition analysis indicated that these cooS genes likely evolved from a common ancestor. Collectively, these data suggest that C. maritimus KKC1 may be highly dependent on CO as a low-potential electron donor to directly reduce ferredoxin and may be more suited to carboxydotrophic growth compared to the acetogenic growth observed in Moorella, which show adaptation at a thermodynamic limit.IMPORTANCECalderihabitans maritimus KKC1 and members of the genus Moorella are phylogenetically related but physiologically distinct. The former is a hydrogenogenic carboxydotroph that can grow on carbon monoxide (CO) with H2 production, whereas the latter include acetogenic bacteria that grow on H2 plus CO2 with acetate production. Both species may require reduced ferredoxin as an actual "energy equivalent," but ferredoxin is a low-potential electron carrier and requires a high-energy substrate as an electron donor for reduction. Comparative genomic analysis revealed that C. maritimus KKC1 lacked specific electron-bifurcating enzymes and possessed six CO dehydrogenases, unlike Moorella species. This suggests that C. maritimus KKC1 may be more dependent on CO, a strong electron donor that can directly reduce ferredoxin via CO dehydrogenase, and may exhibit a survival strategy different from that of acetogenic Moorella, which solves the energetic barrier associated with endergonic reduction of ferredoxin with hydrogen.
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Redl S, Sukumara S, Ploeger T, Wu L, Ølshøj Jensen T, Nielsen AT, Noorman H. Thermodynamics and economic feasibility of acetone production from syngas using the thermophilic production host Moorella thermoacetica. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:150. [PMID: 28616074 PMCID: PMC5469130 DOI: 10.1186/s13068-017-0827-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 05/23/2017] [Indexed: 05/24/2023]
Abstract
BACKGROUND Syngas fermentation is a promising option for the production of biocommodities due to its abundance and compatibility with anaerobic fermentation. Using thermophilic production strains in a syngas fermentation process allows recovery of products with low boiling point from the off-gas via condensation. RESULTS In this study we analyzed the production of acetone from syngas with the hypothetical production host derived from Moorella thermoacetica in a bubble column reactor at 60 °C with respect to thermodynamic and economic feasibility. We determined the cost of syngas production from basic oxygen furnace (BOF) process gas, from natural gas, and from corn stover and identified BOF gas as an economically interesting source for syngas. Taking gas-liquid mass transfer limitations into account, we applied a thermodynamics approach to derive the CO to acetone conversion rate under the process conditions. We estimated variable costs of production of 389 $/t acetone for a representative production scenario from BOF gas with costs for syngas as the main contributor. In comparison, the variable costs of production from natural gas- and corn stover-derived syngas were determined to be higher due to the higher feedstock costs (1724 and 2878 $/t acetone, respectively). CONCLUSION We applied an approach of combining thermodynamic and economic assessment to analyze a hypothetical bioprocess in which the volatile product acetone is produced from syngas with a thermophilic microorganism. Our model allowed us to identify process metrics and quantify the variable production costs for different scenarios. Economical production of bulk chemicals is challenging, making rigorous thermodynamic/economic modeling critical before undertaking an experimental program and as an ongoing guide during the program. We intend this study to give an incentive to apply the demonstrated approach to other bioproduction processes.
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Affiliation(s)
- Stephanie Redl
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sumesh Sukumara
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Tom Ploeger
- DSM Biotechnology Center, PO Box 1, 2600 MA Delft, The Netherlands
| | - Liang Wu
- DSM Biotechnology Center, PO Box 1, 2600 MA Delft, The Netherlands
| | - Torbjørn Ølshøj Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Henk Noorman
- DSM Biotechnology Center, PO Box 1, 2600 MA Delft, The Netherlands
- Department of Biotechnology, Technical University Delft, Delft, The Netherlands
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In silico metabolic engineering of Clostridium ljungdahlii for synthesis gas fermentation. Metab Eng 2016; 38:389-400. [PMID: 27720802 DOI: 10.1016/j.ymben.2016.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 08/19/2016] [Accepted: 10/05/2016] [Indexed: 02/01/2023]
Abstract
Synthesis gas fermentation is one of the most promising routes to convert synthesis gas (syngas; mainly comprised of H2 and CO) to renewable liquid fuels and chemicals by specialized bacteria. The most commonly studied syngas fermenting bacterium is Clostridium ljungdahlii, which produces acetate and ethanol as its primary metabolic byproducts. Engineering of C. ljungdahlii metabolism to overproduce ethanol, enhance the synthesize of the native byproducts lactate and 2,3-butanediol, and introduce the synthesis of non-native products such as butanol and butyrate has substantial commercial value. We performed in silico metabolic engineering studies using a genome-scale reconstruction of C. ljungdahlii metabolism and the OptKnock computational framework to identify gene knockouts that were predicted to enhance the synthesis of these native products and non-native products, introduced through insertion of the necessary heterologous pathways. The OptKnock derived strategies were often difficult to assess because increase product synthesis was invariably accompanied by decreased growth. Therefore, the OptKnock strategies were further evaluated using a spatiotemporal metabolic model of a syngas bubble column reactor, a popular technology for large-scale gas fermentation. Unlike flux balance analysis, the bubble column model accounted for the complex tradeoffs between increased product synthesis and reduced growth rates of engineered mutants within the spatially varying column environment. The two-stage methodology for deriving and evaluating metabolic engineering strategies was shown to yield new C. ljungdahlii gene targets that offer the potential for increased product synthesis under realistic syngas fermentation conditions.
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Shin J, Song Y, Jeong Y, Cho BK. Analysis of the Core Genome and Pan-Genome of Autotrophic Acetogenic Bacteria. Front Microbiol 2016; 7:1531. [PMID: 27733845 PMCID: PMC5039349 DOI: 10.3389/fmicb.2016.01531] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 09/12/2016] [Indexed: 01/07/2023] Open
Abstract
Acetogens are obligate anaerobic bacteria capable of reducing carbon dioxide (CO2) to multicarbon compounds coupled to the oxidation of inorganic substrates, such as hydrogen (H2) or carbon monoxide (CO), via the Wood-Ljungdahl pathway. Owing to the metabolic capability of CO2 fixation, much attention has been focused on understanding the unique pathways associated with acetogens, particularly their metabolic coupling of CO2 fixation to energy conservation. Most known acetogens are phylogenetically and metabolically diverse bacteria present in 23 different bacterial genera. With the increased volume of available genome information, acetogenic bacterial genomes can be analyzed by comparative genome analysis. Even with the genetic diversity that exists among acetogens, the Wood-Ljungdahl pathway, a central metabolic pathway, and cofactor biosynthetic pathways are highly conserved for autotrophic growth. Additionally, comparative genome analysis revealed that most genes in the acetogen-specific core genome were associated with the Wood-Ljungdahl pathway. The conserved enzymes and those predicted as missing can provide insight into biological differences between acetogens and allow for the discovery of promising candidates for industrial applications.
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Affiliation(s)
- Jongoh Shin
- Systems and Synthetic Biology Laboratory, Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Yoseb Song
- Systems and Synthetic Biology Laboratory, Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Yujin Jeong
- Systems and Synthetic Biology Laboratory, Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Byung-Kwan Cho
- Systems and Synthetic Biology Laboratory, Department of Biological Sciences and KI for the BioCentury, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea; Intelligent Synthetic Biology CenterDaejeon, South Korea
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Abstract
Acetogenic bacteria are a diverse group of strictly anaerobic bacteria that utilize the Wood-Ljungdahl pathway for CO2 fixation and energy conservation. These microorganisms play an important part in the global carbon cycle and are a key component of the anaerobic food web. Their most prominent metabolic feature is autotrophic growth with molecular hydrogen and carbon dioxide as the substrates. However, most members also show an outstanding metabolic flexibility for utilizing a vast variety of different substrates. In contrast to autotrophic growth, which is hardly competitive, metabolic flexibility is seen as a key ability of acetogens to compete in ecosystems and might explain the almost-ubiquitous distribution of acetogenic bacteria in anoxic environments. This review covers the latest findings with respect to the heterotrophic metabolism of acetogenic bacteria, including utilization of carbohydrates, lactate, and different alcohols, especially in the model acetogen Acetobacterium woodii Modularity of metabolism, a key concept of pathway design in synthetic biology, together with electron bifurcation, to overcome energetic barriers, appears to be the basis for the amazing substrate spectrum. At the same time, acetogens depend on only a relatively small number of enzymes to expand the substrate spectrum. We will discuss the energetic advantages of coupling CO2 reduction to fermentations that exploit otherwise-inaccessible substrates and the ecological advantages, as well as the biotechnological applications of the heterotrophic metabolism of acetogens.
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Islam MA, Zengler K, Edwards EA, Mahadevan R, Stephanopoulos G. Investigating Moorella thermoacetica metabolism with a genome-scale constraint-based metabolic model. Integr Biol (Camb) 2016; 7:869-82. [PMID: 25994252 DOI: 10.1039/c5ib00095e] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Moorella thermoacetica is a strictly anaerobic, endospore-forming, and metabolically versatile acetogenic bacterium capable of conserving energy by both autotrophic (acetogenesis) and heterotrophic (homoacetogenesis) modes of metabolism. Its metabolic diversity and the ability to efficiently convert a wide range of compounds, including syngas (CO + H2) into acetyl-CoA have made this thermophilic bacterium a promising host for industrial biotechnology applications. However, lack of detailed information on M. thermoacetica's metabolism is a major impediment to its use as a microbial cell factory. In order to overcome this issue, a genome-scale constraint-based metabolic model of Moorella thermoacetica, iAI558, has been developed using its genome sequence and physiological data from published literature. The reconstructed metabolic network of M. thermoacetica comprises 558 metabolic genes, 705 biochemical reactions, and 698 metabolites. Of the total 705 model reactions, 680 are gene-associated while the rest are non-gene associated reactions. The model, in addition to simulating both autotrophic and heterotrophic growth of M. thermoacetica, revealed degeneracy in its TCA-cycle, a common characteristic of anaerobic metabolism. Furthermore, the model helped elucidate the poorly understood energy conservation mechanism of M. thermoacetica during autotrophy. Thus, in addition to generating experimentally testable hypotheses regarding its physiology, such a detailed model will facilitate rapid strain designing and metabolic engineering of M. thermoacetica for industrial applications.
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Affiliation(s)
- M Ahsanul Islam
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Glycerol acts as alternative electron sink during syngas fermentation by thermophilic anaerobe Moorella thermoacetica. J Biosci Bioeng 2016; 121:268-73. [DOI: 10.1016/j.jbiosc.2015.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 07/07/2015] [Accepted: 07/08/2015] [Indexed: 01/03/2023]
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Ma H, Chen X, Liu H, Liu H, Fu B. Improved volatile fatty acids anaerobic production from waste activated sludge by pH regulation: Alkaline or neutral pH? WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 48:397-403. [PMID: 26652215 DOI: 10.1016/j.wasman.2015.11.029] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/11/2015] [Accepted: 11/14/2015] [Indexed: 05/17/2023]
Abstract
In this study, the anaerobic fermentation was carried out for volatile fatty acids (VFAs) production at different pH (between 7.0 and 10.0) conditions with untreated sludge and heat-alkaline pretreated waste activated sludge. In the fermentation with untreated sludge, the extent of hydrolysis of organic matters and extent of acidification at alkaline pH are 54.37% and 30.37%, respectively, resulting in the highest VFAs yield at 235.46mg COD/gVS of three pH conditions. In the fermentation with heat-alkaline pretreated sludge, the acidification rate and VFAs yield at neutral pH are 30.98% and 240.14mg COD/gVS, respectively, which are higher than that at other pH conditions. With the glucose or bovine serum albumin as substrate for VFAs production, the neutral pH showed a higher VFAs concentration than the alkaline pH condition. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the alkaline pH caused low microbial richness. Based on the results in this study, we demonstrated that the alkaline pH is favor of hydrolysis of organic matter in sludge while neutral pH improved the acidogenesis for the VFAs production from sludge. Our finding is obvious different to the previous research and helpful for the understanding of how heat-alkaline pretreatment and alkaline fermentation influence the VFAs production, and beneficial to the development of VFAs production process.
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Affiliation(s)
- Huijun Ma
- School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China
| | - Xingchun Chen
- School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China
| | - He Liu
- School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, 214122 Wuxi, China.
| | - Hongbo Liu
- School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, 214122 Wuxi, China
| | - Bo Fu
- School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, 214122 Wuxi, China
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Schut GJ, Lipscomb GL, Nguyen DMN, Kelly RM, Adams MWW. Heterologous Production of an Energy-Conserving Carbon Monoxide Dehydrogenase Complex in the Hyperthermophile Pyrococcus furiosus. Front Microbiol 2016; 7:29. [PMID: 26858706 PMCID: PMC4731540 DOI: 10.3389/fmicb.2016.00029] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/11/2016] [Indexed: 11/13/2022] Open
Abstract
Carbon monoxide (CO) is an important intermediate in anaerobic carbon fixation pathways in acetogenesis and methanogenesis. In addition, some anaerobes can utilize CO as an energy source. In the hyperthermophilic archaeon Thermococcus onnurineus, which grows optimally at 80°C, CO oxidation and energy conservation is accomplished by a respiratory complex encoded by a 16-gene cluster containing a CO dehydrogenase, a membrane-bound [NiFe]-hydrogenase and a Na+/H+ antiporter module. This complex oxidizes CO, evolves CO2 and H2, and generates a Na+ motive force that is used to conserve energy by a Na+-dependent ATP synthase. Herein we used a bacterial artificial chromosome to insert the 13.2 kb gene cluster encoding the CO-oxidizing respiratory complex of T. onnurineus into the genome of the heterotrophic archaeon, Pyrococcus furiosus, which grows optimally at 100°C. P. furiosus is normally unable to utilize CO, however, the recombinant strain readily oxidized CO and generated H2 at 80°C. Moreover, CO also served as an energy source and allowed the P. furiosus strain to grow with a limiting concentration of sugar or with peptides as the carbon source. Moreover, CO oxidation by P. furiosus was also coupled to the re-utilization, presumably for biosynthesis, of acetate generated by fermentation. The functional transfer of CO utilization between Thermococcus and Pyrococcus species demonstrated herein is representative of the horizontal gene transfer of an environmentally relevant metabolic capability. The transfer of CO utilizing, hydrogen-producing genetic modules also has applications for biohydrogen production and a CO-based industrial platform for various thermophilic organisms.
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Affiliation(s)
- Gerrit J Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
| | - Gina L Lipscomb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
| | - Diep M N Nguyen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
| | - Robert M Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh NC, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
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Sakimoto KK, Wong AB, Yang P. Self-photosensitization of nonphotosynthetic bacteria for solar-to-chemical production. Science 2016; 351:74-7. [PMID: 26721997 DOI: 10.1126/science.aad3317] [Citation(s) in RCA: 507] [Impact Index Per Article: 63.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Improving natural photosynthesis can enable the sustainable production of chemicals. However, neither purely artificial nor purely biological approaches seem poised to realize the potential of solar-to-chemical synthesis. We developed a hybrid approach, whereby we combined the highly efficient light harvesting of inorganic semiconductors with the high specificity, low cost, and self-replication and -repair of biocatalysts. We induced the self-photosensitization of a nonphotosynthetic bacterium, Moorella thermoacetica, with cadmium sulfide nanoparticles, enabling the photosynthesis of acetic acid from carbon dioxide. Biologically precipitated cadmium sulfide nanoparticles served as the light harvester to sustain cellular metabolism. This self-augmented biological system selectively produced acetic acid continuously over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction.
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Affiliation(s)
- Kelsey K Sakimoto
- Department of Chemistry, University of California-Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Andrew Barnabas Wong
- Department of Chemistry, University of California-Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Peidong Yang
- Department of Chemistry, University of California-Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Department of Materials Science and Engineering, University of California-Berkeley, Berkeley, CA 94720, USA. Kavli Energy NanoSciences Institute, Berkeley, CA 94720, USA
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Shen Y, Jarboe L, Brown R, Wen Z. A thermochemical–biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals. Biotechnol Adv 2015; 33:1799-813. [DOI: 10.1016/j.biotechadv.2015.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 12/28/2022]
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Diender M, Stams AJM, Sousa DZ. Pathways and Bioenergetics of Anaerobic Carbon Monoxide Fermentation. Front Microbiol 2015; 6:1275. [PMID: 26635746 PMCID: PMC4652020 DOI: 10.3389/fmicb.2015.01275] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/31/2015] [Indexed: 11/29/2022] Open
Abstract
Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO-rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis, and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.
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Affiliation(s)
- Martijn Diender
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands ; Centre of Biological Engineering, University of Minho Braga, Portugal
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
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