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Wang C, Wei W, Wu L, Wang Y, Dai X, Ni BJ. A Novel Sustainable and Self-Sufficient Biotechnological Strategy for Directly Transforming Sewage Sludge into High-Value Liquid Biochemicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:12520-12531. [PMID: 38953238 DOI: 10.1021/acs.est.4c03165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Sewage sludge, as a carbon-rich byproduct of wastewater treatment, holds significant untapped potential as a renewable resource. Upcycling this troublesome waste stream represents great promise in addressing global escalating energy demands through its wide practice of biochemical recovery concurrently. Here, we propose a biotechnological concept to gain value-added liquid bioproducts from sewage sludge in a self-sufficient manner by directly transforming sludge into medium-chain fatty acids (MCFAs). Our findings suggest that yeast, a cheap and readily available commercial powder, would involve ethanol-type fermentation in chain elongation to achieve abundant MCFA production from sewage sludge using electron donors (i.e., ethanol) and acceptors (i.e., short-chain fatty acids) produced in situ. The enhanced abundance and transcriptional activity of genes related to key enzymes, such as butyryl-CoA dehydrogenase and alcohol dehydrogenase, affirm the robust capacity for the self-sustained production of MCFAs. This is indicative of an effective metabolic network established between yeast and anaerobic microorganisms within this innovative sludge fermentation framework. Furthermore, life cycle assessment and techno-economic analysis evidence the sustainability and economic competitiveness of this biotechnological strategy. Overall, this work provides insights into sewage sludge upgrading independent of additional carbon input, which can be applied in existing anaerobic sludge fermentation infrastructure as well as to develop new applications in a diverse range of industries.
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Affiliation(s)
- Chen Wang
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Lan Wu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Yun Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Bing-Jie Ni
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
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Zhang JZ, Li YZ, Xi ZN, Gao HP, Zhang Q, Liu LC, Li FL, Ma XQ. Engineered acetogenic bacteria as microbial cell factory for diversified biochemicals. Front Bioeng Biotechnol 2024; 12:1395540. [PMID: 39055341 PMCID: PMC11269201 DOI: 10.3389/fbioe.2024.1395540] [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: 03/04/2024] [Accepted: 06/28/2024] [Indexed: 07/27/2024] Open
Abstract
Acetogenic bacteria (acetogens) are a class of microorganisms with conserved Wood-Ljungdahl pathway that can utilize CO and CO2/H2 as carbon source for autotrophic growth and convert these substrates to acetate and ethanol. Acetogens have great potential for the sustainable production of biofuels and bulk biochemicals using C1 gases (CO and CO2) from industrial syngas and waste gases, which play an important role in achieving carbon neutrality. In recent years, with the development and improvement of gene editing methods, the metabolic engineering of acetogens is making rapid progress. With introduction of heterogeneous metabolic pathways, acetogens can improve the production capacity of native products or obtain the ability to synthesize non-native products. This paper reviews the recent application of metabolic engineering in acetogens. In addition, the challenges of metabolic engineering in acetogens are indicated, and strategies to address these challenges are also discussed.
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Affiliation(s)
- Jun-Zhe Zhang
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu-Zhen Li
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Ning Xi
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Hui-Peng Gao
- Sinopec Dalian (Fushun) Research Institute of Petroleum and Petrochemicals, Dalian, China
| | - Quan Zhang
- Sinopec Dalian (Fushun) Research Institute of Petroleum and Petrochemicals, Dalian, China
| | - Li-Cheng Liu
- Key Laboratory of Marine Chemistry Theory and Technology (Ministry of Education), College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, China
| | - Fu-Li Li
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Shandong Energy Institute, Qingdao, China
- Qingdao New Energy Shandong Laboratory, Qingdao, China
| | - Xiao-Qing Ma
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Qingdao New Energy Shandong Laboratory, Qingdao, China
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3
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Chen Y, Chen Y, Dai DZ, Li XL, Song T, Xie J. ZnMo-MOF as anti-CO hydrogen electrocatalyst enhance microbial electrosynthesis for CO/CO 2 conversion. CHEMOSPHERE 2024; 358:142157. [PMID: 38679181 DOI: 10.1016/j.chemosphere.2024.142157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/15/2024] [Accepted: 04/24/2024] [Indexed: 05/01/2024]
Abstract
Microbial electrosynthesis (MES) is an electrically driven technology that can be used for converting CO/CO2 into chemicals. The unique electronic and substrate properties of CO make it an important research target for MES. However, CO can poison the cathode and increase the overpotential of hydrogen evolution reaction (HER), thus reducing the electron transfer rate via H2. This work evaluated the effect of an anti-CO HER catalyst on the performance of MES for CO/CO2 conversion. ZnMo-metal-organic framework (MOF) materials with different calcination temperatures were synthesized. ZnMo-MOF-800 with Mo2C nanoparticles as active centers exhibited excellent resistance to CO toxicity. It also obtained the highest hydrogen evolution and enhanced electron transfer rate in CO atmosphere. MES with ZnMo-MOF-800 cathode and Clostridium ljungdahlii as biocatalyst obtained 0.31 g L-1 d-1 acetate yield, 0.1 g L-1 d-1 butyrate yield, and 0.09 g L-1 d-1 2,3-butanediol yield in CO/CO2, while Pt/C only get 0.076 g L-1 d-1 acetate yield, 0.05 g L-1 d-1 butyrate yield and 0.02 g L-1 d-1 2,3-butanediol yield. ZnMo-MOF-800 was conducive to biofilm formation, enabling it to better resist CO toxicity. This work provides new opportunities for constructing a highly efficient cathode with an anti-CO hydrogen evolution catalyst to enhance CO/CO2 conversion in MES.
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Affiliation(s)
- Yu Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Yuhang Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | | | - Xiang Ling Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Tianshun Song
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
| | - Jingjing Xie
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, PR China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing 211816, PR China.
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Niu C, Zhao X, Shi D, Ying Y, Wu M, Lai CY, Guo J, Hu S, Liu T. Bioreduction of chromate in a syngas-based membrane biofilm reactor. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134195. [PMID: 38581872 DOI: 10.1016/j.jhazmat.2024.134195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/07/2024] [Accepted: 03/31/2024] [Indexed: 04/08/2024]
Abstract
This study leveraged synthesis gas (syngas), a renewable resource attainable through the gasification of biowaste, to achieve efficient chromate removal from water. To enhance syngas transfer efficiency, a membrane biofilm reactor (MBfR) was employed. Long-term reactor operation showed a stable and high-level chromate removal efficiency > 95%, yielding harmless Cr(III) precipitates, as visualised by scanning electron microscopy and energy dispersive X-ray analysis. Corresponding to the short hydraulic retention time of 0.25 days, a high chromate removal rate of 80 µmol/L/d was attained. In addition to chromate reduction, in situ production of volatile fatty acids (VFAs) by gas fermentation was observed. Three sets of in situ batch tests and two groups of ex situ batch tests jointly unravelled the mechanisms, showing that biological chromate reduction was primarily driven by VFAs produced from in situ syngas fermentation, whereas hydrogen originally present in the syngas played a minor role. 16 S rRNA gene amplicon sequencing has confirmed the enrichment of syngas-fermenting bacteria (such as Sporomusa), who performed in situ gas fermentation leading to the synthesis of VFAs, and organics-utilising bacteria (such as Aquitalea), who utilised VFAs to drive chromate reduction. These findings, combined with batch assays, elucidate the pathways orchestrating synergistic interactions between fermentative microbial cohorts and chromate-reducing microorganisms. The findings facilitate the development of cost-effective strategies for groundwater and drinking water remediation and present an alternative application scenario for syngas.
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Affiliation(s)
- Chenkai Niu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Xinyu Zhao
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Danting Shi
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region of China
| | - Yifeng Ying
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Mengxiong Wu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Chun-Yu Lai
- College of Environmental and Resource Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Tao Liu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region of China.
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5
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Heffernan J, Garcia Gonzalez RA, Mahamkali V, McCubbin T, Daygon D, Liu L, Palfreyman R, Harris A, Koepke M, Valgepea K, Nielsen LK, Marcellin E. Adaptive laboratory evolution of Clostridium autoethanogenum to metabolize CO 2 and H 2 enhances growth rates in chemostat and unravels proteome and metabolome alterations. Microb Biotechnol 2024; 17:e14452. [PMID: 38568755 PMCID: PMC10990044 DOI: 10.1111/1751-7915.14452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 03/03/2024] [Accepted: 03/06/2024] [Indexed: 04/05/2024] Open
Abstract
Gas fermentation of CO2 and H2 is an attractive means to sustainably produce fuels and chemicals. Clostridium autoethanogenum is a model organism for industrial CO to ethanol and presents an opportunity for CO2-to-ethanol processes. As we have previously characterized its CO2/H2 chemostat growth, here we use adaptive laboratory evolution (ALE) with the aim of improving growth with CO2/H2. Seven ALE lineages were generated, all with improved specific growth rates. ALE conducted in the presence of 2% CO along with CO2/H2 generated Evolved lineage D, which showed the highest ethanol titres amongst all the ALE lineages during the fermentation of CO2/H2. Chemostat comparison against the parental strain shows no change in acetate or ethanol production, while Evolved D could achieve a higher maximum dilution rate. Multi-omics analyses at steady state revealed that Evolved D has widespread proteome and intracellular metabolome changes. However, the uptake and production rates and titres remain unaltered until investigating their maximum dilution rate. Yet, we provide numerous insights into CO2/H2 metabolism via these multi-omics data and link these results to mutations, suggesting novel targets for metabolic engineering in this bacterium.
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Affiliation(s)
- James Heffernan
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
| | - R. Axayactl Garcia Gonzalez
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
| | | | - Tim McCubbin
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Dara Daygon
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Lian Liu
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Robin Palfreyman
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
| | | | | | - Kaspar Valgepea
- ERA Chair in Gas Fermentation Technologies, Institute of TechnologyUniversity of TartuTartuEstonia
| | - Lars Keld Nielsen
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
| | - Esteban Marcellin
- Australian Institute of Bioengineering and NanotechnologyThe University of QueenslandSt. LuciaQueenslandAustralia
- ARC Centre of Excellence in Synthetic BiologyThe University of QueenslandSt. LuciaQueenslandAustralia
- Queensland Metabolomics and Proteomics Q‐MAPThe University of QueenslandSt. LuciaQueenslandAustralia
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Liu H, Zeng Y, Chen W, Liu C, Sun D, Hu Z, Li P, Xu H, Wu H, Qiu B, Liu X, Dang Y. Effect of different hydrogen evolution rates at cathode on bioelectrochemical reduction of CO 2 to acetate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169744. [PMID: 38176559 DOI: 10.1016/j.scitotenv.2023.169744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/26/2023] [Accepted: 12/26/2023] [Indexed: 01/06/2024]
Abstract
Microbial electrosynthesis (MES) offers a promising approach for converting CO2 into valuable chemicals such as acetate. However, the relative low conversion rate severely limits its practical application. This study investigated the impact of different hydrogen evolution rates on the conversion rate of CO2 to acetate in the MES system. Three potentials (-0.8 V, -0.9 V and -1.0 V) corresponding to various hydrogen evolution rates were set and analyzed, revealing an optimal hydrogen evolution rate, yielding a maximum acetate formation rate of 1410.9 mg/L and 73.5 % coulomb efficiency. The electrochemical findings revealed that an optimal hydrogen evolution rate facilitated the formation of an electroactive biofilm. The microbial community of the cathode biofilm highlighted key genera, including Clostridium and Acetobacterium, which played essential roles in electrosynthesis within the MES system. Notably, a low hydrogen evolution rate failed to provide sufficient energy for the electrochemical reduction of CO2 to acetate, while a high rate led to cathode alkalinization, impeding the reaction and causing significant energy wastage. Therefore, maintaining an appropriate hydrogen evolution rate is crucial for the development of mature electroactive biofilms and achieving optimal performance in the MES system.
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Affiliation(s)
- Huanying Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yiwei Zeng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Wenwen Chen
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Chuanqi Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Dezhi Sun
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Zhen Hu
- School of Environmental Science & Engineering, Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Pengsong Li
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Haiyu Xu
- Qinglin Chuangneng (Shanghai) Technology Co., Ltd, Shanghai 201800, China
| | - Hongbin Wu
- Qinglin Chuangneng (Shanghai) Technology Co., Ltd, Shanghai 201800, China
| | - Bin Qiu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Xinying Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yan Dang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
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Zhang J, Li F, Liu D, Liu Q, Song H. Engineering extracellular electron transfer pathways of electroactive microorganisms by synthetic biology for energy and chemicals production. Chem Soc Rev 2024; 53:1375-1446. [PMID: 38117181 DOI: 10.1039/d3cs00537b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The excessive consumption of fossil fuels causes massive emission of CO2, leading to climate deterioration and environmental pollution. The development of substitutes and sustainable energy sources to replace fossil fuels has become a worldwide priority. Bio-electrochemical systems (BESs), employing redox reactions of electroactive microorganisms (EAMs) on electrodes to achieve a meritorious combination of biocatalysis and electrocatalysis, provide a green and sustainable alternative approach for bioremediation, CO2 fixation, and energy and chemicals production. EAMs, including exoelectrogens and electrotrophs, perform extracellular electron transfer (EET) (i.e., outward and inward EET), respectively, to exchange energy with the environment, whose rate determines the efficiency and performance of BESs. Therefore, we review the synthetic biology strategies developed in the last decade for engineering EAMs to enhance the EET rate in cell-electrode interfaces for facilitating the production of electricity energy and value-added chemicals, which include (1) progress in genetic manipulation and editing tools to achieve the efficient regulation of gene expression, knockout, and knockdown of EAMs; (2) synthetic biological engineering strategies to enhance the outward EET of exoelectrogens to anodes for electricity power production and anodic electro-fermentation (AEF) for chemicals production, including (i) broadening and strengthening substrate utilization, (ii) increasing the intracellular releasable reducing equivalents, (iii) optimizing c-type cytochrome (c-Cyts) expression and maturation, (iv) enhancing conductive nanowire biosynthesis and modification, (v) promoting electron shuttle biosynthesis, secretion, and immobilization, (vi) engineering global regulators to promote EET rate, (vii) facilitating biofilm formation, and (viii) constructing cell-material hybrids; (3) the mechanisms of inward EET, CO2 fixation pathway, and engineering strategies for improving the inward EET of electrotrophic cells for CO2 reduction and chemical production, including (i) programming metabolic pathways of electrotrophs, (ii) rewiring bioelectrical circuits for enhancing inward EET, and (iii) constructing microbial (photo)electrosynthesis by cell-material hybridization; (4) perspectives on future challenges and opportunities for engineering EET to develop highly efficient BESs for sustainable energy and chemical production. We expect that this review will provide a theoretical basis for the future development of BESs in energy harvesting, CO2 fixation, and chemical synthesis.
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Affiliation(s)
- Junqi Zhang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Feng Li
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Dingyuan Liu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Qijing Liu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Hao Song
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
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Wu KK, Zhao L, Wang ZH, Sun ZF, Wu JT, Chen C, Xing DF, Yang SS, Wang AJ, Zhang YF, Ren NQ. Simultaneous biogas upgrading and medium-chain fatty acids production using a dual membrane biofilm reactor. WATER RESEARCH 2024; 249:120915. [PMID: 38029487 DOI: 10.1016/j.watres.2023.120915] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
Utilizing H2-assisted ex-situ biogas upgrading and acetate recovery holds great promise for achieving high value utilization of biogas. However, it faces a significant challenge due to acetate's high solubility and limited economic value. To address this challenge, we propose an innovative strategy for simultaneous upgrading of biogas and the production of medium-chain fatty acids (MCFAs). A series of batch tests evaluated the strategy's efficiency under varying initial gas ratios (v/v) of H2, CH4, CO2, along with varying ethanol concentrations. The results identified the optimal conditions as initial gas ratios of 3H2:3CH4:2CO2 and an ethanol concentration of 241.2 mmol L-1, leading to maximum CH4 purity (97.2 %), MCFAs yield (54.2 ± 2.1 mmol L-1), and MCFAs carbon-flow distribution (62.3 %). Additionally, an analysis of the microbial community's response to varying conditions highlighted the crucial roles played by microorganisms such as Clostridium, Proteiniphilum, Sporanaerobacter, and Bacteroides in synergistically assimilating H2 and CO2 for MCFAs production. Furthermore, a 160-day continuous operation using a dual-membrane aerated biofilm reactor (dMBfR) was conducted. Remarkable achievements were made at a hydraulic retention time of 2 days, including an upgraded CH4 content of 96.4 ± 0.3 %, ethanol utilization ratio (URethanol) of 95.7 %, MCFAs production rate of 28.8 ± 0.3 mmol L-1 d-1, and MCFAs carbon-flow distribution of 70 ± 0.8 %. This enhancement is proved to be an efficient in biogas upgrading and MCFAs production. These results lay the foundation for maximizing the value of biogas, reducing CO2 emissions, and providing valuable insights into resource recovery.
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Affiliation(s)
- Kai-Kai Wu
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Department of Environmental & Resource Engineering, Technical University of Denmark, Lyngby DK-2800, Denmark
| | - Lei Zhao
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Zi-Han Wang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhong-Fang Sun
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Jie-Ting Wu
- School of Environment, Liaoning University, Shenyang 110000, China
| | - Chuan Chen
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - De-Feng Xing
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shan-Shan Yang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ai-Jie Wang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Yi-Feng Zhang
- Department of Environmental & Resource Engineering, Technical University of Denmark, Lyngby DK-2800, Denmark
| | - Nan-Qi Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
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9
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Agrawal A, Yang Z, Blenner M. Engineering Yarrowia lipolytica for the biosynthesis of geraniol. Metab Eng Commun 2023; 17:e00228. [PMID: 38029016 PMCID: PMC10652127 DOI: 10.1016/j.mec.2023.e00228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 10/27/2023] [Accepted: 11/01/2023] [Indexed: 12/01/2023] Open
Abstract
Geraniol is a monoterpene with wide applications in the food, cosmetics, and pharmaceutical industries. Microbial production has largely used model organisms lacking favorable properties for monoterpene production. In this work, we produced geraniol in metabolically engineered Yarrowia lipolytica. First, two plant-derived geraniol synthases (GES) from Catharanthus roseus (Cr) and Valeriana officinalis (Vo) were tested based on previous reports of activity. Both wild type and truncated mutants of GES (without signal peptide targeting chloroplast) were examined by co-expressing with MVA pathway enzymes tHMG1 and IDI1. Truncated CrGES (tCrGES) produced the most geraniol and thus was used for further experimentation. The initial strain was obtained by overexpression of the truncated HMG1, IDI and tCrGES. The acetyl-CoA precursor pool was enhanced by overexpressing mevalonate pathway genes such as ERG10, HMGS or MVK, PMK. The final strain overexpressing 3 copies of tCrGES and single copies of ERG10, HMGS, tHMG1, IDI produced approximately 1 g/L in shake-flask fermentation. This is the first demonstration of geraniol production in Yarrowia lipolytica and the highest de novo titer reported to date in yeast.
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Affiliation(s)
- Ayushi Agrawal
- Department of Chemical and Biomolecular Engineering, 590 Avenue 1743, University of Delaware, Newark, DE, 19713, USA
| | - Zhiliang Yang
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 S. Palmetto Blvd., Clemson, SC, 29634, USA
| | - Mark Blenner
- Department of Chemical and Biomolecular Engineering, 590 Avenue 1743, University of Delaware, Newark, DE, 19713, USA
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 S. Palmetto Blvd., Clemson, SC, 29634, USA
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10
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Bährle R, Böhnke S, Englhard J, Bachmann J, Perner M. Current status of carbon monoxide dehydrogenases (CODH) and their potential for electrochemical applications. BIORESOUR BIOPROCESS 2023; 10:84. [PMID: 38647803 PMCID: PMC10992861 DOI: 10.1186/s40643-023-00705-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/16/2023] [Indexed: 04/25/2024] Open
Abstract
Anthropogenic carbon dioxide (CO2) levels are rising to alarming concentrations in earth's atmosphere, causing adverse effects and global climate changes. In the last century, innovative research on CO2 reduction using chemical, photochemical, electrochemical and enzymatic approaches has been addressed. In particular, natural CO2 conversion serves as a model for many processes and extensive studies on microbes and enzymes regarding redox reactions involving CO2 have already been conducted. In this review we focus on the enzymatic conversion of CO2 to carbon monoxide (CO) as the chemical conversion downstream of CO production render CO particularly attractive as a key intermediate. We briefly discuss the different currently known natural autotrophic CO2 fixation pathways, focusing on the reversible reaction of CO2, two electrons and protons to CO and water, catalyzed by carbon monoxide dehydrogenases (CODHs). We then move on to classify the different type of CODHs, involved catalyzed chemical reactions and coupled metabolisms. Finally, we discuss applications of CODH enzymes in photochemical and electrochemical cells to harness CO2 from the environment transforming it into commodity chemicals.
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Affiliation(s)
- Rebecca Bährle
- Department of Marine Geomicrobiology, Faculty of Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148, Kiel, Germany
| | - Stefanie Böhnke
- Department of Marine Geomicrobiology, Faculty of Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148, Kiel, Germany
| | - Jonas Englhard
- Chemistry of Thin Film Materials, IZNF, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058, Erlangen, Germany
| | - Julien Bachmann
- Chemistry of Thin Film Materials, IZNF, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstr. 3, 91058, Erlangen, Germany
| | - Mirjam Perner
- Department of Marine Geomicrobiology, Faculty of Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148, Kiel, Germany.
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11
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Caivano A, van Winden W, Dragone G, Mussatto SI. Enzyme-constrained metabolic model and in silico metabolic engineering of Clostridium ljungdahlii for the development of sustainable production processes. Comput Struct Biotechnol J 2023; 21:4634-4646. [PMID: 37790242 PMCID: PMC10543971 DOI: 10.1016/j.csbj.2023.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 10/05/2023] Open
Abstract
Constraint-based genome-scale models (GEMs) of microorganisms provide a powerful tool for predicting and analyzing microbial phenotypes as well as for understanding how these are affected by genetic and environmental perturbations. Recently, MATLAB and Python-based tools have been developed to incorporate enzymatic constraints into GEMs. These constraints enhance phenotype predictions by accounting for the enzyme cost of catalyzed model´s reactions, thereby reducing the space of possible metabolic flux distributions. In this study, enzymatic constraints were added to an existing GEM of Clostridium ljungdahlii, a model acetogenic bacterium, by including its enzyme turnover numbers (kcats) and molecular masses, using the Python-based AutoPACMEN approach. When compared to the metabolic model iHN637, the enzyme cost-constrained model (ec_iHN637) obtained in our study showed an improved predictive ability of growth rate and product profile. The model ec_iHN637 was then employed to perform in silico metabolic engineering of C. ljungdahlii, by using the OptKnock computational framework to identify knockouts to enhance the production of desired fermentation products. The in silico metabolic engineering was geared towards increasing the production of fermentation products by C. ljungdahlii, with a focus on the utilization of synthesis gas and CO2. This resulted in different engineering strategies for overproduction of valuable metabolites under different feeding conditions, without redundant knockouts for different products. Importantly, the results of the in silico engineering results indicated that the mixotrophic growth of C. ljungdahlii is a promising approach to coupling improved cell growth and acetate and ethanol productivity with net CO2 fixation.
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Affiliation(s)
- Antonio Caivano
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800, Kongens Lyngby, Denmark
| | - Wouter van Winden
- DSM-Firmenich Science & Research - Bioprocess Innovation, Rosalind Franklin Biotechnology Center, Alexander Fleminglaan 1, 2613 AX, Delft, the Netherlands
| | - Giuliano Dragone
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800, Kongens Lyngby, Denmark
| | - Solange I. Mussatto
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800, Kongens Lyngby, Denmark
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12
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Wu KK, Zhao L, Zheng XC, Sun ZF, Wang ZH, Chen C, Xing DF, Yang SS, Ren NQ. Recovery of methane and acetate during ex-situ biogas upgrading via novel dual-membrane aerated biofilm reactor. BIORESOURCE TECHNOLOGY 2023; 382:129181. [PMID: 37210035 DOI: 10.1016/j.biortech.2023.129181] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/29/2023] [Accepted: 05/13/2023] [Indexed: 05/22/2023]
Abstract
Biological biogas upgrading has been well-proven to be a promising approach for renewable bioenergy recovery, but hydrogen (H2)-assisted ex-situ biogas upgrading is hindered by a large solubility discrepancy between H2 and carbon dioxide (CO2). This study established a new dual-membrane aerated biofilm reactor (dMBfR) to improve the upgrading efficiency. Results showed that dMBfR operated at 1.25 atm H2 partial pressure, 1.5 atm biogas partial pressure, and 1.0 d hydraulic retention time could significantly improve the efficiency. The maximum methane purity of 97.6%, acetate production rate of 34.5 mmol L-1d-1, and H2 and CO2 utilization ratios of 96.5% and 96.3% were achieved. Further analysis showed that the improved performances of biogas upgrading and acetate recovery were positively correlated with the total abundances of functional microorganisms. Taken together, these results suggest that the dMBfR, which facilitates the precise CO2 and H2 supply, is an ideal approach for efficient biological biogas upgrading.
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Affiliation(s)
- Kai-Kai Wu
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Lei Zhao
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Xiao-Chuan Zheng
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhong-Fang Sun
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zi-Han Wang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chuan Chen
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - De-Feng Xing
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shan-Shan Yang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Nan-Qi Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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13
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Lo J, Wu C, Humphreys JR, Yang B, Jiang Z, Wang X, Maness P, Tsesmetzis N, Xiong W. Thermodynamic and Kinetic Modeling Directs Pathway Optimization for Isopropanol Production in a Gas-Fermenting Bacterium. mSystems 2023; 8:e0127422. [PMID: 36971551 PMCID: PMC10134883 DOI: 10.1128/msystems.01274-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Highly efficient bioproduction from gaseous substrates (e.g., hydrogen and carbon oxides) will require systematic optimization of the host microbes. To date, the rational redesign of gas-fermenting bacteria is still in its infancy, due in part to the lack of quantitative and precise metabolic knowledge that can direct strain engineering.
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14
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Ceron-Chafla P, de Vrieze J, Rabaey K, van Lier JB, Lindeboom REF. Steering the product spectrum in high-pressure anaerobic processes: CO 2 partial pressure as a novel tool in biorefinery concepts. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:27. [PMID: 36803622 PMCID: PMC9938588 DOI: 10.1186/s13068-023-02262-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 01/05/2023] [Indexed: 02/19/2023]
Abstract
BACKGROUND Elevated CO2 partial pressure (pCO2) has been proposed as a potential steering parameter for selective carboxylate production in mixed culture fermentation. It is anticipated that intermediate product spectrum and production rates, as well as changes in the microbial community, are (in)directly influenced by elevated pCO2. However, it remains unclear how pCO2 interacts with other operational conditions, namely substrate specificity, substrate-to-biomass (S/X) ratio and the presence of an additional electron donor, and what effect pCO2 has on the exact composition of fermentation products. Here, we investigated possible steering effects of elevated pCO2 combined with (1) mixed substrate (glycerol/glucose) provision; (2) subsequent increments in substrate concentration to increase the S/X ratio; and (3) formate as an additional electron donor. RESULTS Metabolite predominance, e.g., propionate vs. butyrate/acetate, and cell density, depended on interaction effects between pCO2-S/X ratio and pCO2-formate. Individual substrate consumption rates were negatively impacted by the interaction effect between pCO2-S/X ratio and were not re-established after lowering the S/X ratio and adding formate. The product spectrum was influenced by the microbial community composition, which in turn, was modified by substrate type and the interaction effect between pCO2-formate. High propionate and butyrate levels strongly correlated with Negativicutes and Clostridia predominance, respectively. After subsequent pressurized fermentation phases, the interaction effect between pCO2-formate enabled a shift from propionate towards succinate production when mixed substrate was provided. CONCLUSIONS Overall, interaction effects between elevated pCO2, substrate specificity, high S/X ratio and availability of reducing equivalents from formate, rather than an isolated pCO2 effect, modified the proportionality of propionate, butyrate and acetate in pressurized mixed substrate fermentations at the expense of reduced consumption rates and increased lag-phases. The interaction effect between elevated pCO2 and formate was beneficial for succinate production and biomass growth with a glycerol/glucose mixture as the substrate. The positive effect may be attributed to the availability of extra reducing equivalents, likely enhanced carbon fixating activity and hindered propionate conversion due to increased concentration of undissociated carboxylic acids.
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Affiliation(s)
- Pamela Ceron-Chafla
- Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands.
| | - Jo de Vrieze
- grid.5342.00000 0001 2069 7798Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Korneel Rabaey
- grid.5342.00000 0001 2069 7798Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium ,grid.510907.aCenter for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Coupure Links 653, 9000 Ghent, Belgium
| | - Jules B. van Lier
- grid.5292.c0000 0001 2097 4740Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
| | - Ralph E. F. Lindeboom
- grid.5292.c0000 0001 2097 4740Sanitary Engineering Section, Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
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15
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Biowaste upcycling into second-generation microbial protein through mixed-culture fermentation. Trends Biotechnol 2023; 41:197-213. [PMID: 35989113 DOI: 10.1016/j.tibtech.2022.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 01/24/2023]
Abstract
Securing a sustainable protein supply at the global level is among the greatest challenges currently faced by humanity. Alternative protein sources, such as second-generation microbial protein (MP), could give rise to innovative circular bioeconomy practices, synthesizing high-value bioproducts through the recovery and upcycling of resources from overabundant biowastes and residues. Within such a multi-feedstock biorefinery scenario, the wide range of microbial pathways and networks that characterize mixed microbial cultures, offers interesting and not yet fully explored advantages over conventional monoculture-based processes. In this review, we combine a comprehensive analysis of waste recovery platforms for second-generation MP production with a critical evaluation of the research gaps and potentials offered by mixed culture-based MP fermentation processes.
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16
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Wu KK, Zhao L, Sun ZF, Wang ZH, Chen C, Ren HY, Yang SS, Ren NQ. Synergistic effect of hydrogen and nanoscale zero-valent iron on ex-situ biogas upgrading and acetate recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159100. [PMID: 36174700 DOI: 10.1016/j.scitotenv.2022.159100] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/16/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Hydrogen (H2) assisted ex-situ biogas upgrading and liquid chemicals production can augment the fossil fuel-dominated energy market, and alleviate CO2-induced global warming. Recent investigations confirmed that nanoscale zero-valent iron (nZVI) enabled the enhancement of anaerobic digestion for biogas production. However, little is known about the effect of nZVI on the downstream ex-situ biogas upgrading. Herein, different levels (0 mg L-1, 100 mg L-1, 200 mg L-1, 500 mg L-1, 1000 mg L-1, 2000 mg L-1) of nZVI were added for H2-assisted ex-situ biogas upgrading, to study whether nZVI could impact the biomethane purity and acetate yield for the first time. Results showed that all tested nZVI levels were favorable for biogas upgrading in the presence of H2, the highest biomethane content (94.1 %, v/v), the CO2 utilization ratio (95.9 %), and acetate yield (19.4 mmol L-1) were achieved at 500 mg L-1 nZVI, respectively. Further analysis indicated that increased biogas upgrading efficiency was related to an increase in extracellular polymeric substances, which ensures the microbial activity and stability of the ex-situ biogas upgrading. Microbial community characterization showed that the Petrimonas, Romboutsia, Acidaminococcus, and Clostridium predominated the microbiome during biogas upgrading at 500 mg L-1 nZVI with H2 supply. These results suggested that nZVI and H2 contributed jointly to promoting the bioconversion of CO2 in biogas to acetate. The findings could be helpful for paving a new way for efficient simultaneous ex-situ biogas upgrading and liquid chemicals recovery.
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Affiliation(s)
- Kai-Kai Wu
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Lei Zhao
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Zhong-Fang Sun
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zi-Han Wang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chuan Chen
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hong-Yu Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shan-Shan Yang
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Nan-Qi Ren
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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17
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Li C, Wang R, Wang J, Liu L, Li H, Zheng H, Ni J. A Highly Compatible Phototrophic Community for Carbon-Negative Biosynthesis. Angew Chem Int Ed Engl 2023; 62:e202215013. [PMID: 36378012 DOI: 10.1002/anie.202215013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/09/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022]
Abstract
CO2 sequestration engineering is promising for carbon-negative biosynthesis, and artificial communities can solve more complex problems than monocultures. However, obtaining an ideal photosynthetic community is still a great challenge. Herein, we describe the development of a highly compatible photosynthetic community (HCPC) by integrating a sucrose-producing CO2 sequestration module and a super-coupled module. The cyanobacteria CO2 sequestration module was obtained using stepwise metabolic engineering and then coupled with the efficient sucrose utilization module Vibrio natriegens. Integrated omics analysis indicated that enhanced photosynthetic electron transport and extracellular vesicles promote intercellular communication. Additionally, the HCPC was used to channel CO2 into valuable chemicals, enabling the overall release of -22.27 to -606.59 kgCO2 e kg-1 in the end products. This novel light-driven community could facilitate circular economic implementation in the future.
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Affiliation(s)
- Chaofeng Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ruoyu Wang
- School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiawei Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Liangxu Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hengrun Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Haotian Zheng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jun Ni
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China
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18
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Qian J, Zheng P. Fixation of CO2 from ethanol fermentation for succinic acid production in a dual-chamber bioreactor system. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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19
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Joseph RC, Sandoval NR. Single and multiplexed gene repression in solventogenic Clostridium via Cas12a-based CRISPR interference. Synth Syst Biotechnol 2022; 8:148-156. [PMID: 36687471 PMCID: PMC9842803 DOI: 10.1016/j.synbio.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/28/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022] Open
Abstract
The Gram-positive, spore-forming, obligate anaerobic firmicute species that make up the Clostridium genus have broad feedstock consumption capabilities and produce value-added metabolic products, but genetic manipulation is difficult, limiting their broad appeal. CRISPR-Cas systems have recently been applied to Clostridium species, primarily using Cas9 as a counterselection marker in conjunction with plasmid-based homologous recombination. CRISPR interference is a method that reduces gene expression of specific genes via precision targeting of a nuclease deficient Cas effector protein. Here, we develop a dCas12a-based CRISPR interference system for transcriptional gene repression in multiple mesophilic Clostridium species. We show the Francisella novicida Cas12a-based system has a broader applicability due to the low GC content in Clostridium species compared to CRISPR Cas systems derived from other bacteria. We demonstrate >99% reduction in transcript levels of targeted genes in Clostridium acetobutylicum and >75% reduction in Clostridium pasteurianum. We also demonstrate multiplexed repression via use of a single synthetic CRISPR array, achieving 99% reduction in targeted gene expression and elucidating a unique metabolic profile for their reduced expression. Overall, this work builds a foundation for high throughput genetic screens without genetic editing, a key limitation in current screening methods used in the Clostridium community.
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Affiliation(s)
| | - Nicholas R. Sandoval
- Corresponding author. Department of Chemical and Biomolecular Engineering, Tulane University, St. Charles Ave, New Orleans, LA, 70118, United States.
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20
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Recent progress in the engineering of C1-utilizing microbes. Curr Opin Biotechnol 2022; 78:102836. [PMID: 36334444 DOI: 10.1016/j.copbio.2022.102836] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 11/06/2022]
Abstract
The global climate crisis has led to the transition toward the sustainable production of chemicals and fuels with a low carbon footprint. Microbial utilization of one-carbon (C1) substrates, such as carbon dioxide, carbon monoxide, methane, formate, and methanol, may be a promising replacement for the current fossil fuel-based industry. However, natural C1-utilizing microbes are currently unsuitable for industrial applications because of their slow growth and low carbon conversion efficiency, which results in low productivity and yield. Here, we review the recent achievements in engineering C1-utilizing microbes with improved carbon assimilation efficiency and describe the development of synthetic microorganisms by introducing natural C1 assimilation pathways in non-C1-utilizing microbes. Finally, we outline the future directions for realizing the industrial potential of C1-utilizing microbes.
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21
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Thi Quynh Le H, Lee EY. Biological production of 2-propanol from propane using a metabolically engineered type I methanotrophic bacterium. BIORESOURCE TECHNOLOGY 2022; 362:127835. [PMID: 36031125 DOI: 10.1016/j.biortech.2022.127835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
2-Propanol is a widely used industrial solvents. Herein, we employed a unique feature of type I methanotrophic bacterium Methylotuvimicrobium alcaliphilum 20Z possessing only particulate methane monooxygenase (pMMO) for one-step direct production of pure 2-propanol from propane. By maintaining cell growth on glycerol, and after deletion of both Ca2+-dependent and La3+-dependent methanol dehydrogenases, propane was converted to 2-propanol by pMMO. Although most of the 2-propanol produced was further oxidized to acetone, deletion of active alcohol dehydrogenase, concomitant with synchronous overexpression of secondary alcohol dehydrogenase, significantly inhibited such undesirable oxidation. As a result, a remarkable enhancement (263 mg/L) of 2-propanol was achieved for 120 h by increasing cell growth with a supply of 50% (v/v) propane in headspace. This is the first demonstration to develop an engineered methanotrophic strain for the one-step direct production of pure 2-propanol from propane using one-phase cultivation without the supply of chemical inhibitors or additional reducing-power sources.
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Affiliation(s)
- Hoa Thi Quynh Le
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin 17104, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin 17104, Republic of Korea.
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22
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Lo J, Humphreys JR, Magnusson L, Wachter B, Urban C, Hebdon SD, Xiong W, Chou KJ, Ching Maness P. Acetogenic production of 3-Hydroxybutyrate using a native 3-Hydroxybutyryl-CoA Dehydrogenase. Front Microbiol 2022; 13:948369. [PMID: 36003933 PMCID: PMC9393629 DOI: 10.3389/fmicb.2022.948369] [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: 05/19/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
Abstract
3-Hydroxybutyrate (3HB) is a product of interest as it is a precursor to the commercially produced bioplastic polyhydroxybutyrate. It can also serve as a platform for fine chemicals, medicines, and biofuels, making it a value-added product and feedstock. Acetogens non-photosynthetically fix CO2 into acetyl-CoA and have been previously engineered to convert acetyl-CoA into 3HB. However, as acetogen metabolism is poorly understood, those engineering efforts have had varying levels of success. 3HB, using acetyl-CoA as a precursor, can be synthesized by a variety of different pathways. Here we systematically compare various pathways to produce 3HB in acetogens and discover a native (S)-3-hydroxybutyryl-CoA dehydrogenase, hbd2, responsible for endogenous 3HB production. In conjunction with the heterologous thiolase atoB and CoA transferase ctfAB, hbd2 overexpression improves yields of 3HB on both sugar and syngas (CO/H2/CO2), outperforming the other tested pathways. These results uncovered a previously unknown 3HB production pathway, inform data from prior metabolic engineering efforts, and have implications for future physiological and biotechnological anaerobic research.
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23
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Okoye-Chine CG, Otun K, Shiba N, Rashama C, Ugwu SN, Onyeaka H, Okeke CT. Conversion of carbon dioxide into fuels—A review. J CO2 UTIL 2022. [DOI: 10.1016/j.jcou.2022.102099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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24
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He Y, Kennes C, Lens PNL. Enhanced solventogenesis in syngas bioconversion: Role of process parameters and thermodynamics. CHEMOSPHERE 2022; 299:134425. [PMID: 35351479 DOI: 10.1016/j.chemosphere.2022.134425] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Biofuels, such as ethanol and butanol, obtained from carbon monoxide-rich gas or syngas bioconversion (solventogenesis) are an attractive alternative to traditional fermentation processes with merits of no competition with food production and sustainability. However, there is a lack of comprehensive understanding of some key process parameters and mechanisms enhancing solventogenesis during the fermentation process. This review provides an overview of the current state of the art of the main influencing factors during the syngas fermentation process catalyzed by acetogenic species as well as undefined mixed cultures. The role of syngas pressure, syngas components, fermentation pH, temperature, trace metals, organic compounds and additional materials is overviewed. As a so far hardly considered approach, thermodynamic calculations of the Gibbs free energy of CO conversion to acetic acid, ethanol, butyric acid and butanol under different CO pressures and pH at 25, 33 and 55 °C are also addressed and reviewed. Strategies for enhancing mass transfer and longer carbon chain solvent production are considered as well.
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Affiliation(s)
- Yaxue He
- National University of Ireland Galway, H91 TK33, Galway, Ireland; Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research - Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña (UDC), E-15008, La Coruña, Spain.
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research - Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña (UDC), E-15008, La Coruña, Spain
| | - Piet N L Lens
- National University of Ireland Galway, H91 TK33, Galway, Ireland
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25
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Vamsi Krishna K, Bharathi N, George Shiju S, Alagesan Paari K, Malaviya A. An updated review on advancement in fermentative production strategies for biobutanol using Clostridium spp. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:47988-48019. [PMID: 35562606 DOI: 10.1007/s11356-022-20637-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 04/30/2022] [Indexed: 06/15/2023]
Abstract
A significant concern of our fuel-dependent era is the unceasing exhaustion of petroleum fuel supplies. In parallel to this, environmental issues such as the greenhouse effect, change in global climate, and increasing global temperature must be addressed on a priority basis. Biobutanol, which has fuel characteristics comparable to gasoline, has attracted global attention as a viable green fuel alternative among the many biofuel alternatives. Renewable biomass could be used for the sustainable production of biobutanol by the acetone-butanol-ethanol (ABE) pathway. Non-extinguishable resources, such as algal and lignocellulosic biomass, and starch are some of the most commonly used feedstock for fermentative production of biobutanol, and each has its particular set of advantages. Clostridium, a gram-positive endospore-forming bacterium that can produce a range of compounds, along with n-butanol is traditionally known for its biobutanol production capabilities. Clostridium fermentation produces biobased n-butanol through ABE fermentation. However, low butanol titer, a lack of suitable feedstock, and product inhibition are the primary difficulties in biobutanol synthesis. Critical issues that are essential for sustainable production of biobutanol include (i) developing high butanol titer producing strains utilizing genetic and metabolic engineering approaches, (ii) renewable biomass that could be used for biobutanol production at a larger scale, and (iii) addressing the limits of traditional batch fermentation by integrated bioprocessing technologies with effective product recovery procedures that have increased the efficiency of biobutanol synthesis. Our paper reviews the current progress in all three aspects of butanol production and presents recent data on current practices in fermentative biobutanol production technology.
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Affiliation(s)
- Kondapalli Vamsi Krishna
- Applied and Industrial Biotechnology Laboratory, CHRIST (Deemed-to-Be University), Hosur road, Bangalore, Karnataka, India
| | - Natarajan Bharathi
- Department of Life Sciences, CHRIST (Deemed to Be University), Bengaluru, India
| | - Shon George Shiju
- Applied and Industrial Biotechnology Laboratory, CHRIST (Deemed-to-Be University), Hosur road, Bangalore, Karnataka, India
| | | | - Alok Malaviya
- Applied and Industrial Biotechnology Laboratory, CHRIST (Deemed-to-Be University), Hosur road, Bangalore, Karnataka, India.
- Department of Life Sciences, CHRIST (Deemed to Be University), Bengaluru, India.
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26
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Vees CA, Herwig C, Pflügl S. Mixotrophic co-utilization of glucose and carbon monoxide boosts ethanol and butanol productivity of continuous Clostridium carboxidivorans cultures. BIORESOURCE TECHNOLOGY 2022; 353:127138. [PMID: 35405210 DOI: 10.1016/j.biortech.2022.127138] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
In this study, continuous cultivations of C.carboxidivorans to study heterotrophic and mixotrophic conversion of glucose and H2, CO2, and CO were established. Glucose fermentations at pH 6 showed a high ratio of alcohol-to-acid production of 2.79 mol mol-1. While H2 or CO2 were not utilized together with glucose, CO feeding drastically increased the combined alcohol titer to 9.1 g l-1. Specifically, CO enhanced acetate (1.9-fold) and ethanol (1.7-fold) production and triggered chain elongation to butanol (1.5-fold) production but did not change the alcohol:acid ratio. Flux balance analysis showed that CO served both as a carbon and energy source, and CO mixotrophy displayed a carbon and energy efficiency of 45 and 77%, respectively. This study expands the knowledge on physiology and metabolism of C.carboxidivorans and can serve as the starting point for rational engineering and process intensification to establish efficient production of alcohols and acids from carbon waste.
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Affiliation(s)
- Charlotte Anne Vees
- Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
| | - Christoph Herwig
- Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria; Competence Center CHASE GmbH, Altenbergerstraße 69, 4040 Linz, Austria.
| | - Stefan Pflügl
- Technische Universität Wien, Institute of Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
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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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Lee H, Bae J, Jin S, Kang S, Cho BK. Engineering Acetogenic Bacteria for Efficient One-Carbon Utilization. Front Microbiol 2022; 13:865168. [PMID: 35615514 PMCID: PMC9124964 DOI: 10.3389/fmicb.2022.865168] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/19/2022] [Indexed: 12/03/2022] Open
Abstract
C1 gases, including carbon dioxide (CO2) and carbon monoxide (CO), are major contributors to climate crisis. Numerous studies have been conducted to fix and recycle C1 gases in order to solve this problem. Among them, the use of microorganisms as biocatalysts to convert C1 gases to value-added chemicals is a promising solution. Acetogenic bacteria (acetogens) have received attention as high-potential biocatalysts owing to their conserved Wood–Ljungdahl (WL) pathway, which fixes not only CO2 but also CO. Although some metabolites have been produced via C1 gas fermentation on an industrial scale, the conversion of C1 gases to produce various biochemicals by engineering acetogens has been limited. The energy limitation of acetogens is one of the challenges to overcome, as their metabolism operates at a thermodynamic limit, and the low solubility of gaseous substrates results in a limited supply of cellular energy. This review provides strategies for developing efficient platform strains for C1 gas conversion, focusing on engineering the WL pathway. Supplying liquid C1 substrates, which can be obtained from CO2, or electricity is introduced as a strategy to overcome the energy limitation. Future prospective approaches on engineering acetogens based on systems and synthetic biology approaches are also discussed.
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Affiliation(s)
- Hyeonsik Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jiyun Bae
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Sangrak Jin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seulgi Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- *Correspondence: Byung-Kwan Cho,
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Li Z, Cai J, Gao Y, Zhang L, Liang Q, Hao W, Jiang Y, Jianxiong Zeng R. Efficient production of medium chain fatty acids in microbial electrosynthesis with simultaneous bio-utilization of carbon dioxide and ethanol. BIORESOURCE TECHNOLOGY 2022; 352:127101. [PMID: 35367601 DOI: 10.1016/j.biortech.2022.127101] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Microbial electrosynthesis (MES) is a promising technology for chemicals production driven by renewable energy. However, how the medium chain fatty acids (MCFAs) production in MES is affected by the method of chain elongation is not clear, and no direct evidence is provided yet for a simultaneous bio-utilization of CO2 and ethanol. In this study, different methods of chain elongation in MES reactors were investigated. During in-situ chain elongation, a maximum caproate concentration of 11.9 ± 0.6 g L-1 was achieved, while the C6 specificity (56.4% ± 0.5%) was much lower than that of ex-situ chain elongation (78.7% ± 1.5%). Carbon distribution and reduction degree balance indicated a simultaneous bio-utilization of CO2 and ethanol, and it was validated by the isotope tracer technique. MCFAs-forming microbes, acetogens, and electrochemically active microorganisms were enriched. This study provides fundamental insights relevant to the carbon and electron fluxes driven by electricity.
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Affiliation(s)
- Zhigang Li
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jiayi Cai
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yu Gao
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lixia Zhang
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Qinjun Liang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wen Hao
- Department of Applied Chemistry, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yong Jiang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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30
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Oh HJ, Ko JK, Gong G, Lee SM, Um Y. Production of Hexanol as the Main Product Through Syngas Fermentation by Clostridium carboxidivorans P7. Front Bioeng Biotechnol 2022; 10:850370. [PMID: 35547160 PMCID: PMC9081523 DOI: 10.3389/fbioe.2022.850370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/04/2022] [Indexed: 11/24/2022] Open
Abstract
The production of hexanol from syngas by acetogens has gained attention as a replacement for petroleum-derived hexanol, which is widely used in the chemical synthesis and plastic industries. However, acetogenic bacteria generally produce C2 compounds (e.g., acetate and ethanol) as the main products. In this study, the gas fermentation conditions favorable for hexanol production were investigated at different temperatures (30-37°C) and CO gas contents (30-70%) in batch gas fermentation. Hexanol production increased from 0.02 to 0.09 g/L when the cultivation temperature was lowered from 37 to 30°C. As the CO content increased from 30 to 70%, the CO consumption rate and hexanol production (yield, titer, and ratio of C6 compound to total products) increased with the CO content. When 70% CO gas was repeatedly provided by flushing the headspace of the bottles at 30°C, the total alcohol production increased to 4.32 g/L at the expense of acids. Notably, hexanol production (1.90 g/L) was higher than that of ethanol (1.20 g/L) and butanol (1.20 g/L); this is the highest level of hexanol produced in gas fermentation to date and the first report of hexanol as the main product. Hexanol production was further enhanced to 2.34 g/L when 2 g/L ethanol was supplemented at the beginning of 70% CO gas refeeding fermentation. Particularly, hexanol productivity was significantly enhanced to 0.18 g/L/day while the supplemented ethanol was consumed, indicating that the conversion of ethanol to acetyl-CoA and reducing equivalents positively affected hexanol production. These optimized culture conditions (gas fermentation at 30°C and refeeding with 70% CO gas) and ethanol supplementation provide an effective and sustainable approach for bio-hexanol production.
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Affiliation(s)
- Hyun Ju Oh
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul, South Korea
- Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon, South Korea
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31
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Feng SS, Li W, Hu YJ, Feng JX, Deng J. The biological activity and application of Monascus pigments: a mini review. INTERNATIONAL JOURNAL OF FOOD ENGINEERING 2022. [DOI: 10.1515/ijfe-2021-0235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Abstract
Monascus pigments (MPs), as secondary metabolites of Monascus, are microbial pigments which have been used for thousands of years. MPs are widely used in food industry as food pigments and preservatives, which have the stability of light resistance, high temperature resistance and acid-base change resistance. In addition, the antioxidant, antibacterial, antiviral and anti-tumor biological activities of MPs have also attracted people’s attention. Moreover, Due to the presence of citrinin, the safety of MPs still needs to be discussed and explored. In this paper, the production, biological activity, application in various fields and methods of detection and reduction of citrinin of MPs were reviewed, which provide new insights into the study and safe application related to human different diseases, medicines or health care products with MPs as active substances.
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Affiliation(s)
- Shan-Shan Feng
- Hunan Province Key Laboratory of Edible Forestry Resources Safety and Processing Utilization , National Engineering Research Center of Rice and Byproduct Deep Processing , College of Food Science and Engineering , Central South University of Forestry and Technology , Changsha , China
- College of Life Sciences and Chemistry , Hunan University of Technology, Zhuzhou , China
| | - Wen Li
- Hunan Province Key Laboratory of Edible Forestry Resources Safety and Processing Utilization , National Engineering Research Center of Rice and Byproduct Deep Processing , College of Food Science and Engineering , Central South University of Forestry and Technology , Changsha , China
- College of Life Sciences and Chemistry , Hunan University of Technology, Zhuzhou , China
| | - Yong-Jun Hu
- Department of Ultrasound , Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal University , Changsha , Hunan 410002 , China
| | - Jian-Xiang Feng
- College of Life Sciences and Chemistry , Hunan University of Technology, Zhuzhou , China
| | - Jing Deng
- Hunan Province Key Laboratory of Edible Forestry Resources Safety and Processing Utilization , National Engineering Research Center of Rice and Byproduct Deep Processing , College of Food Science and Engineering , Central South University of Forestry and Technology , Changsha , China
- College of Life Sciences and Chemistry , Hunan University of Technology, Zhuzhou , China
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32
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Dahle ML, Papoutsakis ET, Antoniewicz MR. 13C-metabolic flux analysis of Clostridium ljungdahlii illuminates its core metabolism under mixotrophic culture conditions. Metab Eng 2022; 72:161-170. [DOI: 10.1016/j.ymben.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/25/2022] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
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Carbon-negative production of acetone and isopropanol by gas fermentation at industrial pilot scale. Nat Biotechnol 2022; 40:335-344. [DOI: 10.1038/s41587-021-01195-w] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/09/2021] [Indexed: 12/21/2022]
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34
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Wei Z, Ahmed Mohamed T, Zhao L, Zhu Z, Zhao Y, Wu J. Microhabitat drive microbial anabolism to promote carbon sequestration during composting. BIORESOURCE TECHNOLOGY 2022; 346:126577. [PMID: 34923079 DOI: 10.1016/j.biortech.2021.126577] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Transforming organic waste into stable carbon by composting is an eco-friendly way. However, the complex environment, huge microbial community and complicated metabolic of composting have limited the directional transformation of organic carbon, which is also not conducive to the fixation of organic carbon. Therefore, this review is based on the formation of humus, a stable by-product of composting, to expound how to promote carbon fixation by increasing the yield of humus. Firstly, we have clarified the transformation regularity of organic matter during composting. Meanwhile, the microhabitat factors affecting microbial catabolism and anabolism were deeply analyzed, in order to provide a theoretical basis for the micro habitat regulation of directional transformation of organic matter during composting. Given that, a method to adjust the directional humification and stabilization of organic carbon has been proposed. Hoping the rapid reduction and efficient stabilization of organic waste can be realized according to this method.
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Affiliation(s)
- Zimin Wei
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Taha Ahmed Mohamed
- College of Life Science, Northeast Agricultural University, Harbin 150030, China; Soil, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt
| | - Li Zhao
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Zechen Zhu
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Yue Zhao
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Junqiu Wu
- College of Life Science, Northeast Agricultural University, Harbin 150030, China.
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35
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Pavan M, Reinmets K, Garg S, Mueller AP, Marcellin E, Köpke M, Valgepea K. Advances in systems metabolic engineering of autotrophic carbon oxide-fixing biocatalysts towards a circular economy. Metab Eng 2022; 71:117-141. [DOI: 10.1016/j.ymben.2022.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 12/16/2022]
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36
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Hong Y, Zeng AP. Biosynthesis Based on One-Carbon Mixotrophy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2022; 180:351-371. [DOI: 10.1007/10_2021_198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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37
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Jia D, He M, Tian Y, Shen S, Zhu X, Wang Y, Zhuang Y, Jiang W, Gu Y. Metabolic Engineering of Gas-Fermenting Clostridium ljungdahlii for Efficient Co-production of Isopropanol, 3-Hydroxybutyrate, and Ethanol. ACS Synth Biol 2021; 10:2628-2638. [PMID: 34549587 DOI: 10.1021/acssynbio.1c00235] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rational design and modification of autotrophic bacteria to efficiently produce high-value chemicals and biofuels are crucial for establishing a sustainable and economically viable process for one-carbon (C1) source utilization, which, however, remains a challenge in metabolic engineering. In this study, autotrophic Clostridium ljungdahlii was metabolically engineered to efficiently co-produce three important bulk chemicals, isopropanol, 3-hydroxybutyrate (3-HB), and ethanol (together, IHE), using syngas (CO2/CO). An artificial isopropanol-producing pathway was first constructed and optimized in C. ljungdahlii to achieve an efficient production of isopropanol and an unexpected product, 3-HB. Based on this finding, an endogenous active dehydrogenase capable of converting acetoacetate to 3-HB was identified in C. ljungdahlii, thereby revealing an efficient 3-HB-producing pathway. The engineered strain was further optimized to reassimilate acetic acid and synthesize 3-HB by introducing heterologous functional genes. Finally, the best-performing strain was able to produce 13.4, 3.0, and 28.4 g/L of isopropanol, 3-HB, and ethanol, respectively, in continuous gas fermentation. Therefore, this work represents remarkable progress in microbial production of bulk chemicals using C1 gases.
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Affiliation(s)
- Dechen Jia
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meiyu He
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yi Tian
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Shaohuang Shen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xianfeng Zhu
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yonghong Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Weihong Jiang
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yang Gu
- Key Laboratory of Synthetic Biology, The State Key Laboratory of Plant Carbon-Nitrogen Assimilation, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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Arslan K, Veiga MC, Kennes C. Autotrophic (C 1-gas) versus heterotrophic (fructose) accumulation of acetic acid and ethanol in Clostridium aceticum. BIORESOURCE TECHNOLOGY 2021; 337:125485. [PMID: 34320764 DOI: 10.1016/j.biortech.2021.125485] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
The influence of the carbon source on the metabolism and growth of Clostridium aceticum was investigated, supplying either CO or fructose as sole carbon source. The acid and solvent production patterns were determined under either autotrophic or heterotrophic conditions, elucidating the effect of pH on the substrate's bioconversion pattern. The highest maximum specific growth rate was observed with CO, under the organism's optimal growth conditions, reaching 0.052 h-1 and an acetic acid concentration of 18 g·L-1. The production of 4.4 g·L-1 ethanol was also possible, after medium acidification, during CO bioconversion. Conversely, formic acid inhibition was observed during fructose fermentation under optimal growth conditions. In the latter experiments, it was not possible to stimulate solvent production when growing C. aceticum on fructose, despite applying the same medium acidification strategy as with CO, showing the selective effect of the carbon source (autotrophic vs heterotrophic) on the metabolic pattern and solventogenesis.
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Affiliation(s)
- Kübra Arslan
- Chemical Engineering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), BIOENGIN group, University of La Coruña, Rúa da Fraga 10, La Coruña 15008, Spain
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), BIOENGIN group, University of La Coruña, Rúa da Fraga 10, La Coruña 15008, Spain
| | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), BIOENGIN group, University of La Coruña, Rúa da Fraga 10, La Coruña 15008, Spain.
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Atasoy M, Cetecioglu Z. Bioaugmented Mixed Culture by Clostridium aceticum to Manipulate Volatile Fatty Acids Composition From the Fermentation of Cheese Production Wastewater. Front Microbiol 2021; 12:658494. [PMID: 34539589 PMCID: PMC8446653 DOI: 10.3389/fmicb.2021.658494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/30/2021] [Indexed: 11/13/2022] Open
Abstract
Production of targeted volatile fatty acid (VFA) composition by fermentation is a promising approach for upstream and post-stream VFA applications. In the current study, the bioaugmented mixed microbial culture by Clostridium aceticum was used to produce an acetic acid dominant VFA mixture. For this purpose, anaerobic sequencing batch reactors (bioaugmented and control) were operated under pH 10 and fed by cheese processing wastewater. The efficiency and stability of the bioaugmentation strategy were monitored using the production and composition of VFA, the quantity of C. aceticum (by qPCR), and bacterial community profile (16S rRNA Illumina Sequencing). The bioaugmented mixed culture significantly increased acetic acid concentration in the VFA mixture (from 1170 ± 18 to 122 ± 9 mgCOD/L) compared to the control reactor. Furthermore, the total VFA production (from 1254 ± 11 to 5493 ± 36 mgCOD/L) was also enhanced. Nevertheless, the bioaugmentation could not shift the propionic acid dominancy in the VFA mixture. The most significant effect of bioaugmentation on the bacterial community profile was seen in the relative abundance of the Thermoanaerobacterales Family III. Incertae sedis, its relative abundance increased simultaneously with the gene copy number of C. aceticum during bioaugmentation. These results suggest that there might be a syntropy between species of Thermoanaerobacterales Family III. Incertae sedis and C. aceticum. The cycle analysis showed that 6 h (instead of 24 h) was adequate retention time to achieve the same acetic acid and total VFA production efficiency. Biobased acetic acid production is widely applicable and economically competitive with petroleum-based production, and this study has the potential to enable a new approach as produced acetic acid dominant VFA can replace external carbon sources for different processes (such as denitrification) in WWTPs. In this way, the higher treatment efficiency for WWTPs can be obtained by recovered substrate from the waste streams that promote a circular economy approach.
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Affiliation(s)
- Merve Atasoy
- Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Zeynep Cetecioglu
- Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden
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Neuendorf CS, Vignolle GA, Derntl C, Tomin T, Novak K, Mach RL, Birner-Grünberger R, Pflügl S. A quantitative metabolic analysis reveals Acetobacterium woodii as a flexible and robust host for formate-based bioproduction. Metab Eng 2021; 68:68-85. [PMID: 34537366 DOI: 10.1016/j.ymben.2021.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/30/2021] [Accepted: 09/15/2021] [Indexed: 11/24/2022]
Abstract
Cheap and renewable feedstocks such as the one-carbon substrate formate are emerging for sustainable production in a growing chemical industry. We investigated the acetogen Acetobacterium woodii as a potential host for bioproduction from formate alone and together with autotrophic and heterotrophic co-substrates by quantitatively analyzing physiology, transcriptome, and proteome in chemostat cultivations in combination with computational analyses. Continuous cultivations with a specific growth rate of 0.05 h-1 on formate showed high specific substrate uptake rates (47 mmol g-1 h-1). Co-utilization of formate with H2, CO, CO2 or fructose was achieved without catabolite repression and with acetate as the sole metabolic product. A transcriptomic comparison of all growth conditions revealed a distinct adaptation of A. woodii to growth on formate as 570 genes were changed in their transcript level. Transcriptome and proteome showed higher expression of the Wood-Ljungdahl pathway during growth on formate and gaseous substrates, underlining its function during utilization of one-carbon substrates. Flux balance analysis showed varying flux levels for the WLP (0.7-16.4 mmol g-1 h-1) and major differences in redox and energy metabolism. Growth on formate, H2/CO2, and formate + H2/CO2 resulted in low energy availability (0.20-0.22 ATP/acetate) which was increased during co-utilization with CO or fructose (0.31 ATP/acetate for formate + H2/CO/CO2, 0.75 ATP/acetate for formate + fructose). Unitrophic and mixotrophic conversion of all substrates was further characterized by high energetic efficiencies. In silico analysis of bioproduction of ethanol and lactate from formate and autotrophic and heterotrophic co-substrates showed promising energetic efficiencies (70-92%). Collectively, our findings reveal A. woodii as a promising host for flexible and simultaneous bioconversion of multiple substrates, underline the potential of substrate co-utilization to improve the energy availability of acetogens and encourage metabolic engineering of acetogenic bacteria for the efficient synthesis of bulk chemicals and fuels from sustainable one carbon substrates.
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Affiliation(s)
- Christian Simon Neuendorf
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
| | - Gabriel A Vignolle
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
| | - Christian Derntl
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
| | - Tamara Tomin
- Technische Universität Wien, Institute for Chemical Technologies and Analytics, Research Group Bioanalytics, Getreidemarkt 9, 1060, Vienna, Austria.
| | - Katharina Novak
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
| | - Robert L Mach
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
| | - Ruth Birner-Grünberger
- Technische Universität Wien, Institute for Chemical Technologies and Analytics, Research Group Bioanalytics, Getreidemarkt 9, 1060, Vienna, Austria; Medical University of Graz, Diagnostic and Research Institute of Pathology, Center for Medical Research, Stiftingtalstrasse 24, 8036, Graz, Austria.
| | - Stefan Pflügl
- Technische Universität Wien, Institute for Chemical, Environmental and Bioscience Engineering, Research Area Biochemical Engineering, Gumpendorfer Straße 1a, 1060, Vienna, Austria.
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Flores AD, Holland SC, Mhatre A, Sarnaik AP, Godar A, Onyeabor M, Varman AM, Wang X, Nielsen DR. A coculture-coproduction system designed for enhanced carbon conservation through inter-strain CO 2 recycling. Metab Eng 2021; 67:387-395. [PMID: 34365009 DOI: 10.1016/j.ymben.2021.08.001] [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: 04/27/2021] [Revised: 07/08/2021] [Accepted: 08/04/2021] [Indexed: 11/30/2022]
Abstract
Carbon loss in the form of CO2 is an intrinsic and persistent challenge faced during conventional and advanced biofuel production from biomass feedstocks. Current mechanisms for increasing carbon conservation typically require the provision of reduced co-substrates as additional reducing equivalents. This need can be circumvented, however, by exploiting the natural heterogeneity of lignocellulosic sugars mixtures and strategically using specific fractions to drive complementary CO2 emitting vs. CO2 fixing pathways. As a demonstration of concept, a coculture-coproduction system was developed by pairing two catabolically orthogonal Escherichia coli strains; one converting glucose to ethanol (G2E) and the other xylose to succinate (X2S). 13C-labeling studies reveled that G2E + X2S cocultures were capable of recycling 24% of all evolved CO2 and achieved a carbon conservation efficiency of 77%; significantly higher than the 64% achieved when all sugars are instead converted to just ethanol. In addition to CO2 exchange, the latent exchange of pyruvate between strains was discovered, along with significant carbon rearrangement within X2S.
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Affiliation(s)
- Andrew D Flores
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Steven C Holland
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States
| | - Apurv Mhatre
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Aditya P Sarnaik
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Amanda Godar
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States
| | - Moses Onyeabor
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States
| | - Arul M Varman
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, AZ, 85287, United States.
| | - David R Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, AZ 85287, ECG 301, 501 E. Tyler Mall, Arizona, 85287, United States.
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42
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Joseph RC, Kelley SQ, Kim NM, Sandoval NR. Metabolic Engineering and the Synthetic Biology Toolbox for
Clostridium. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Liu N, Stephanopoulos G. Metabolic Engineering Perspectives. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bio-conversion of CO 2 into biofuels and other value-added chemicals via metabolic engineering. Microbiol Res 2021; 251:126813. [PMID: 34274880 DOI: 10.1016/j.micres.2021.126813] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/28/2021] [Accepted: 07/04/2021] [Indexed: 11/24/2022]
Abstract
Carbon dioxide (CO2) occurs naturally in the atmosphere as a trace gas, which is produced naturally as well as by anthropogenic activities. CO2 is a readily available source of carbon that in principle can be used as a raw material for the synthesis of valuable products. The autotrophic organisms are naturally equipped to convert CO2 into biomass by obtaining energy from sunlight or inorganic electron donors. This autotrophic CO2 fixation has been exploited in biotechnology, and microbial cell factories have been metabolically engineered to convert CO2 into biofuels and other value-added bio-based chemicals. A variety of metabolic engineering efforts for CO2 fixation ranging from basic copy, paste, and fine-tuning approaches to engineering and testing of novel synthetic CO2 fixing pathways have been demonstrated. In this paper, we review the current advances and innovations in metabolic engineering for bio-conversion of CO2 into bio biofuels and other value-added bio-based chemicals.
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45
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Xu S, Qiao Z, Luo L, Sun Y, Wong JWC, Geng X, Ni J. On-site CO 2 bio-sequestration in anaerobic digestion: Current status and prospects. BIORESOURCE TECHNOLOGY 2021; 332:125037. [PMID: 33840612 DOI: 10.1016/j.biortech.2021.125037] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The advantages of anaerobic digestion (AD) technology in organic solid waste treatment for bioenergy recovery are evidenced in worldwide. Recently, more attention has been paid to on-site biogas research, as well as biogenic CO2 sequestration from AD plant, to promote "carbon neutral". Single-phase and two-phase AD system can be incorporated with various CO2 bioconversion technologies through H2 mediated CO2 bioconversion (in-situ and ex-situ biogas upgrading), or other emerging strategies for CO2 fixation without exogenous H2 injection; these include in-situ direct interspecies electron transfer reinforcement, electromethanogenesis, and off-gas reutilization. The existing and potential scenarios for on-site CO2 bio-sequestration within the AD framework are reviewed from the perspectives of metabolic pathways, functional microorganisms, the limitations on reaction kinetics. This review concluded that on-site CO2 bio-sequestration is a promising solution to reduce greenhouse gas emissions and increase renewable energy recovery.
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Affiliation(s)
- Suyun Xu
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Zihao Qiao
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Liwen Luo
- Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong Special Administrative Region, China; Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China
| | - Yongqi Sun
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Jonathan Woon-Chung Wong
- Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong Special Administrative Region, China; Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China.
| | - Xueyu Geng
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Jing Ni
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
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46
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Bang J, Ahn JH, Lee JA, Hwang CH, Kim GB, Lee J, Lee SY. Synthetic Formatotrophs for One-Carbon Biorefinery. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2100199. [PMID: 34194943 PMCID: PMC8224422 DOI: 10.1002/advs.202100199] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/06/2021] [Indexed: 06/13/2023]
Abstract
The use of CO2 as a carbon source in biorefinery is of great interest, but the low solubility of CO2 in water and the lack of efficient CO2 assimilation pathways are challenges to overcome. Formic acid (FA), which can be easily produced from CO2 and more conveniently stored and transported than CO2, is an attractive CO2-equivalent carbon source as it can be assimilated more efficiently than CO2 by microorganisms and also provides reducing power. Although there are native formatotrophs, they grow slowly and are difficult to metabolically engineer due to the lack of genetic manipulation tools. Thus, much effort is exerted to develop efficient FA assimilation pathways and synthetic microorganisms capable of growing solely on FA (and CO2). Several innovative strategies are suggested to develop synthetic formatotrophs through rational metabolic engineering involving new enzymes and reconstructed FA assimilation pathways, and/or adaptive laboratory evolution (ALE). In this paper, recent advances in development of synthetic formatotrophs are reviewed, focusing on biological FA and CO2 utilization pathways, enzymes involved and newly developed, and metabolic engineering and ALE strategies employed. Also, future challenges in cultivating formatotrophs to higher cell densities and producing chemicals from FA and CO2 are discussed.
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Affiliation(s)
- Junho Bang
- Metabolic and Biomolecular Engineering National Research LaboratoryDepartment of Chemical and Biomolecular Engineering (BK21 Plus Program)Institute for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Systems Metabolic Engineering and Systems Healthcare Cross‐Generation Collaborative LaboratoryKAISTDaejeon34141Republic of Korea
| | - Jung Ho Ahn
- Metabolic and Biomolecular Engineering National Research LaboratoryDepartment of Chemical and Biomolecular Engineering (BK21 Plus Program)Institute for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Systems Metabolic Engineering and Systems Healthcare Cross‐Generation Collaborative LaboratoryKAISTDaejeon34141Republic of Korea
| | - Jong An Lee
- Metabolic and Biomolecular Engineering National Research LaboratoryDepartment of Chemical and Biomolecular Engineering (BK21 Plus Program)Institute for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Systems Metabolic Engineering and Systems Healthcare Cross‐Generation Collaborative LaboratoryKAISTDaejeon34141Republic of Korea
| | - Chang Hun Hwang
- Metabolic and Biomolecular Engineering National Research LaboratoryDepartment of Chemical and Biomolecular Engineering (BK21 Plus Program)Institute for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Systems Metabolic Engineering and Systems Healthcare Cross‐Generation Collaborative LaboratoryKAISTDaejeon34141Republic of Korea
| | - Gi Bae Kim
- Metabolic and Biomolecular Engineering National Research LaboratoryDepartment of Chemical and Biomolecular Engineering (BK21 Plus Program)Institute for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Systems Metabolic Engineering and Systems Healthcare Cross‐Generation Collaborative LaboratoryKAISTDaejeon34141Republic of Korea
| | - Jinwon Lee
- Department of Chemical and Biomolecular EngineeringSogang UniversitySeoul04107Republic of Korea
- C1 Gas Refinery R&D CenterSogang UniversitySeoul04107Republic of Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research LaboratoryDepartment of Chemical and Biomolecular Engineering (BK21 Plus Program)Institute for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Systems Metabolic Engineering and Systems Healthcare Cross‐Generation Collaborative LaboratoryKAISTDaejeon34141Republic of Korea
- BioInformatics Research Center and BioProcess Engineering Research CenterKAISTDaejeon34141Republic of Korea
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Flaiz M, Ludwig G, Bengelsdorf FR, Dürre P. Production of the biocommodities butanol and acetone from methanol with fluorescent FAST-tagged proteins using metabolically engineered strains of Eubacterium limosum. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:117. [PMID: 33971948 PMCID: PMC8111989 DOI: 10.1186/s13068-021-01966-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/29/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND The interest in using methanol as a substrate to cultivate acetogens increased in recent years since it can be sustainably produced from syngas and has the additional benefit of reducing greenhouse gas emissions. Eubacterium limosum is one of the few acetogens that can utilize methanol, is genetically accessible and, therefore, a promising candidate for the recombinant production of biocommodities from this C1 carbon source. Although several genetic tools are already available for certain acetogens including E. limosum, the use of brightly fluorescent reporter proteins is still limited. RESULTS In this study, we expanded the genetic toolbox of E. limosum by implementing the fluorescence-activating and absorption shifting tag (FAST) as a fluorescent reporter protein. Recombinant E. limosum strains that expressed the gene encoding FAST in an inducible and constitutive manner were constructed. Cultivation of these recombinant strains resulted in brightly fluorescent cells even under anaerobic conditions. Moreover, we produced the biocommodities butanol and acetone from methanol with recombinant E. limosum strains. Therefore, we used E. limosum cultures that produced FAST-tagged fusion proteins of the bifunctional acetaldehyde/alcohol dehydrogenase or the acetoacetate decarboxylase, respectively, and determined the fluorescence intensity and product concentrations during growth. CONCLUSIONS The addition of FAST as an oxygen-independent fluorescent reporter protein expands the genetic toolbox of E. limosum. Moreover, our results show that FAST-tagged fusion proteins can be constructed without negatively impacting the stability, functionality, and productivity of the resulting enzyme. Finally, butanol and acetone can be produced from methanol using recombinant E. limosum strains expressing genes encoding fluorescent FAST-tagged fusion proteins.
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Affiliation(s)
- Maximilian Flaiz
- Institute of Microbiology and Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
| | - Gideon Ludwig
- Institute of Microbiology and Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Frank R Bengelsdorf
- Institute of Microbiology and Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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48
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Fackler N, Heffernan J, Juminaga A, Doser D, Nagaraju S, Gonzalez-Garcia RA, Simpson SD, Marcellin E, Köpke M. Transcriptional control of Clostridium autoethanogenum using CRISPRi. Synth Biol (Oxf) 2021; 6:ysab008. [PMID: 33928195 PMCID: PMC8062849 DOI: 10.1093/synbio/ysab008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/15/2021] [Accepted: 02/01/2021] [Indexed: 02/06/2023] Open
Abstract
Gas fermentation by Clostridium autoethanogenum is a commercial process for the sustainable biomanufacturing of fuels and valuable chemicals using abundant, low-cost C1 feedstocks (CO and CO2) from sources such as inedible biomass, unsorted and nonrecyclable municipal solid waste, and industrial emissions. Efforts toward pathway engineering and elucidation of gene function in this microbe have been limited by a lack of genetic tools to control gene expression and arduous genome engineering methods. To increase the pace of progress, here we developed an inducible CRISPR interference (CRISPRi) system for C. autoethanogenum and applied that system toward transcriptional repression of genes with ostensibly crucial functions in metabolism.
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Affiliation(s)
| | - James Heffernan
- Australian Institute for Bioengineering and Nanotechnology, ARC Centre of Excellence in Synthetic Biology & Metabolomics Australia, The University of Queensland, Brisbane, Queensland, 4072 Australia
| | | | | | | | - R Axayacatl Gonzalez-Garcia
- Australian Institute for Bioengineering and Nanotechnology, ARC Centre of Excellence in Synthetic Biology & Metabolomics Australia, The University of Queensland, Brisbane, Queensland, 4072 Australia
| | | | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, ARC Centre of Excellence in Synthetic Biology & Metabolomics Australia, The University of Queensland, Brisbane, Queensland, 4072 Australia
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49
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Kato J, Takemura K, Kato S, Fujii T, Wada K, Iwasaki Y, Aoi Y, Matsushika A, Murakami K, Nakashimada Y. Metabolic engineering of Moorella thermoacetica for thermophilic bioconversion of gaseous substrates to a volatile chemical. AMB Express 2021; 11:59. [PMID: 33891189 PMCID: PMC8065083 DOI: 10.1186/s13568-021-01220-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 04/09/2021] [Indexed: 11/26/2022] Open
Abstract
Gas fermentation is one of the promising bioprocesses to convert CO2 or syngas to important chemicals. Thermophilic gas fermentation of volatile chemicals has the potential for the development of consolidated bioprocesses that can simultaneously separate products during fermentation. This study reports the production of acetone from CO2 and H2, CO, or syngas by introducing the acetone production pathway using acetyl–coenzyme A (Ac-CoA) and acetate produced via the Wood–Ljungdahl pathway in Moorella thermoacetica. Reducing the carbon flux from Ac-CoA to acetate through genetic engineering successfully enhanced acetone productivity, which varied on the basis of the gas composition. The highest acetone productivity was obtained with CO–H2, while autotrophic growth collapsed with CO2–H2. By adding H2 to CO, the acetone productivity from the same amount of carbon source increased compared to CO gas only, and the maximum specific acetone production rate also increased from 0.04 to 0.09 g-acetone/g-dry cell/h. Our development of the engineered thermophilic acetogen M. thermoacetica, which grows at a temperature higher than the boiling point of acetone (58 °C), would pave the way for developing a consolidated process with simplified and cost-effective recovery via condensation following gas fermentation.
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50
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Lo J, Humphreys JR, Jack J, Urban C, Magnusson L, Xiong W, Gu Y, Ren ZJ, Maness PC. The Metabolism of Clostridium ljungdahlii in Phosphotransacetylase Negative Strains and Development of an Ethanologenic Strain. Front Bioeng Biotechnol 2020; 8:560726. [PMID: 33195125 PMCID: PMC7653027 DOI: 10.3389/fbioe.2020.560726] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 10/05/2020] [Indexed: 11/13/2022] Open
Abstract
The sustainable production of chemicals from non-petrochemical sources is one of the greatest challenges of our time. CO2 release from industrial activity is not environmentally friendly yet provides an inexpensive feedstock for chemical production. One means of addressing this problem is using acetogenic bacteria to produce chemicals from CO2, waste streams, or renewable resources. Acetogens are attractive hosts for chemical production for many reasons: they can utilize a variety of feedstocks that are renewable or currently waste streams, can capture waste carbon sources and covert them to products, and can produce a variety of chemicals with greater carbon efficiency over traditional fermentation technologies. Here we investigated the metabolism of Clostridium ljungdahlii, a model acetogen, to probe carbon and electron partitioning and understand what mechanisms drive product formation in this organism. We utilized CRISPR/Cas9 and an inducible riboswitch to target enzymes involved in fermentation product formation. We focused on the genes encoding phosphotransacetylase (pta), aldehyde ferredoxin oxidoreductases (aor1 and aor2), and bifunctional alcohol/aldehyde dehydrogenases (adhE1 and adhE2) and performed growth studies under a variety of conditions to probe the role of those enzymes in the metabolism. Finally, we demonstrated a switch from acetogenic to ethanologenic metabolism by these manipulations, providing an engineered bacterium with greater application potential in biorefinery industry.
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Affiliation(s)
- Jonathan Lo
- National Renewable Energy Laboratory, Golden, CO, United States
| | | | - Joshua Jack
- Andlinger Center for Energy and Environment, Princeton University, Princeton, NJ, United States
| | - Chris Urban
- National Renewable Energy Laboratory, Golden, CO, United States
| | | | - Wei Xiong
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Yang Gu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Zhiyong Jason Ren
- Andlinger Center for Energy and Environment, Princeton University, Princeton, NJ, United States
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