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Wang N, Gao M, Liu S, Zhu W, Zhang Y, Wang X, Sun H, Guo Y, Wang Q. Electrochemical promotion of organic waste fermentation: Research advances and prospects. ENVIRONMENTAL RESEARCH 2024; 244:117422. [PMID: 37866529 DOI: 10.1016/j.envres.2023.117422] [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: 07/14/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/24/2023]
Abstract
The current methods of treating organic waste suffer from limited resource usage and low product value. Research and development of value-added products emerges as an unavoidable trend for future growth. Electro-fermentation (EF) is a technique employed to stimulate cell proliferation, expedite microbial metabolism, and enhance the production of value-added products by administering minute voltages or currents in the fermentation system. This method represents a novel research direction lying at the crossroads of electrochemistry and biology. This article documents the current progress of EF for a range of value-added products, including gaseous fuels, organic acids, and other organics. It also presents novel value-added products, such as 1,3-propanediol, 3-hydroxypropionic acid, succinic acid, acrylic acid, and lysine. The latest research trends suggest a focus on EF for cogeneration of value-added products, studying microbial community structure and electroactive bacteria, exploring electron transfer mechanisms in EF systems, developing effective methods for nutrient recovery of nitrogen and phosphorus, optimizing EF conditions, and utilizing biosensors and artificial neural networks in this area. In this paper, an analysis is conducted on the challenges that currently exist regarding the selection of conductive materials, optimization of electrode materials, and development of bioelectrochemical system (BES) coupling processes in EF systems. The aim is to provide a reference for the development of more efficient, advanced, and value-added EF technologies. Overall, this paper aims to provide references and ideas for the development of more efficient and advanced EF technology.
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Affiliation(s)
- Nuohan Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Ming Gao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Shuo Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wenbin Zhu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yuanchun Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xiaona Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Haishu Sun
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yan Guo
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Qunhui Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Tianjin College, University of Science and Technology Beijing, Tianjin, 301811, China.
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Salar-García MJ, Ortiz-Martínez VM, Sánchez-Segado S, Valero Sánchez R, Sáez López A, Lozano Blanco LJ, Godínez-Seoane C. Sustainable Production of Biofuels and Biochemicals via Electro-Fermentation Technology. Molecules 2024; 29:834. [PMID: 38398584 PMCID: PMC10891623 DOI: 10.3390/molecules29040834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/04/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
The energy crisis and climate change are two of the most concerning issues for human beings nowadays. For that reason, the scientific community is focused on the search for alternative biofuels to conventional fossil fuels as well as the development of sustainable processes to develop a circular economy. Bioelectrochemical processes have been demonstrated to be useful for producing bioenergy and value-added products from several types of waste. Electro-fermentation has gained great attention in the last few years due to its potential contribution to biofuel and biochemical production, e.g., hydrogen, methane, biopolymers, etc. Conventional fermentation processes pose several limitations in terms of their practical and economic feasibility. The introduction of two electrodes in a bioreactor allows the regulation of redox instabilities that occur in conventional fermentation, boosting the overall process towards a high biomass yield and enhanced product formation. In this regard, key parameters such as the type of culture, the nature of the electrodes as well as the operating conditions are crucial in order to maximize the production of biofuels and biochemicals via electro-fermentation technology. This article comprises a critical overview of the benefits and limitations of this emerging bio-electrochemical technology and its contribution to the circular economy.
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Affiliation(s)
- María José Salar-García
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Alfonso XIII, Aulario C, 30203 Cartagena, Spain;
| | - Víctor Manuel Ortiz-Martínez
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Sergio Sánchez-Segado
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Raúl Valero Sánchez
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Alfonso XIII, Aulario C, 30203 Cartagena, Spain;
| | - Antonia Sáez López
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Luis Javier Lozano Blanco
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
| | - Carlos Godínez-Seoane
- Department of Chemical and Environmental Engineering, Technical University of Cartagena (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain; (S.S.-S.); (A.S.L.); (L.J.L.B.); (C.G.-S.)
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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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Gu L, Xiao X, Yup Lee S, Lai B, Solem C. Superior anodic electro-fermentation by enhancing capacity for extracellular electron transfer. BIORESOURCE TECHNOLOGY 2023; 389:129813. [PMID: 37776913 DOI: 10.1016/j.biortech.2023.129813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/02/2023]
Abstract
Anodic electro-fermentation (AEF), where an anode replaces the terminal electron acceptor, shows great promise. Recently a Lactococcus lactis strain blocked in NAD+ regeneration was demonstrated to use ferricyanide as an alternative electron acceptor to support fast growth, but the need for high concentrations of this non-regenerated electron acceptor limits practical applications. To address this, growth of this L. lactis strain, and an adaptively evolved (ALE) mutant with enhanced ferricyanide respiration capacity were investigated using an anode as electron acceptor in a bioelectrochemical system (BES) setup. Both strains grew well, however, the ALE mutant significantly faster. The ALE mutant almost exclusively generated 2,3-butanediol, whereas its parent strain mainly produced acetoin. The ALE mutant interacted efficiently with the anode, achieving a record high current density of 0.81 ± 0.05 mA/cm2. It is surprising that a Lactic Acid Bacterium, with fermentative metabolism, interacts so well with an anode, which demonstrates the potential of AEF.
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Affiliation(s)
- Liuyan Gu
- National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark
| | - Xinxin Xiao
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark
| | - Sang Yup Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Bin Lai
- BMBF junior research group Biophotovoltaics, Helmholtz Center for Environmental Research - UFZ, Leipzig 04318, Germany.
| | - Christian Solem
- National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
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5
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Ye X, Zheng T, Zhang W, Dong W, Wu H, Ma J, Jiang M. Membrane engineering of Escherichia coli based on "Building bridges" and "Digging tunnels" to improve electro-fermentation of succinate. Bioelectrochemistry 2023; 152:108455. [PMID: 37163911 DOI: 10.1016/j.bioelechem.2023.108455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 04/26/2023] [Accepted: 04/28/2023] [Indexed: 05/12/2023]
Abstract
Succinate is the end product of anaerobic metabolism of Escherichia coli, and its over-production needs abundant reducing force. Electro-fermentation (EF) is a novel biotechnology to steer and control fermentative processes by supplying extra electrons. However, E.coli is a non-electroactive strain which needs the support of electron shuttle in EF. Here, membrane engineering strategies of "Building bridges" via screening direct electron transport pathway and "Digging tunnels" via screening membrane porins were developed to improve the transmembrane transport of electron during the cathodic electro-fermentation (CEF). As a result, the total electron quantity during electro-fermentation was increased from 1.21 mmol to 7.90 mmol, and succinate yield was increased by 23.3% when these strategies simultaneously were applied to the succinate candidate E. coli Suc260. Hence, this study provides a reference mode for designing and constructing non-electroactive bacteria for electro-fermentation of reductive metabolites.
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Affiliation(s)
- Xiaohan Ye
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Tianwen Zheng
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China
| | - Hao Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China.
| | - Jiangfeng Ma
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China.
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211800, PR China
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Production of 3-Hydroxypropionic Acid from Renewable Substrates by Metabolically Engineered Microorganisms: A Review. Molecules 2023; 28:molecules28041888. [PMID: 36838875 PMCID: PMC9960984 DOI: 10.3390/molecules28041888] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
3-Hydroxypropionic acid (3-HP) is a platform chemical with a wide range of existing and potential applications, including the production of poly(3-hydroxypropionate) (P-3HP), a biodegradable plastic. The microbial synthesis of 3-HP has attracted significant attention in recent years due to its green and sustainable properties. In this paper, we provide an overview of the microbial synthesis of 3-HP from four major aspects, including the main 3-HP biosynthesis pathways and chassis strains used for the construction of microbial cell factories, the major carbon sources used for 3-HP production, and fermentation processes. Recent advances in the biosynthesis of 3-HP and related metabolic engineering strategies are also summarized. Finally, this article provides insights into the future direction of 3-HP biosynthesis.
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7
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Garg A, Jers C, Hwang HJ, Kalantari A, Ventina I, Mijakovic I. Engineering Bacillus subtilis for production of 3-hydroxypropanoic acid. Front Bioeng Biotechnol 2023; 11:1101232. [PMID: 36726744 PMCID: PMC9885095 DOI: 10.3389/fbioe.2023.1101232] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/04/2023] [Indexed: 01/17/2023] Open
Abstract
3-Hydroxypropionic acid (3-HP) is a valuable platform chemical that is used as a precursor for several higher value-added chemical products. There is an increased interest in development of cell factories as a means for the synthesis of 3-HP and various other platform chemicals. For more than a decade, concentrated effort has been invested by the scientific community towards developing bio-based approaches for the production of 3-HP using primarily Escherichia coli and Klebsiella pneumoniae as production hosts. These hosts however might not be optimal for applications in e.g., food industry due primarily to endotoxin production and the pathogenic origin of particularly the K. pneumoniae. We have previously demonstrated that the generally recognized as safe organism Bacillus subtilis can be engineered to produce 3-HP using glycerol, an abundant by-product of the biodiesel industry, as substrate. For commercial exploitation, there is a need to substantially increase the titer. In the present study, we optimized the bioprocess conditions and further engineered the B. subtilis 3-HP production strain. Thereby, using glycerol as substrate, we were able to improve 3-HP production in a 1-L bioreactor to a final titer of 22.9 g/L 3-HP.
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Affiliation(s)
- Abhroop Garg
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Carsten Jers
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Hee Jin Hwang
- Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden,Department of Molecular Science and Technology, Ajou University, World cup-ro, Yeongtong-gu, Suwon-si, South Korea
| | - Aida Kalantari
- Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ildze Ventina
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Ivan Mijakovic
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark,Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden,*Correspondence: Ivan Mijakovic,
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8
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Sun Y, Kokko M, Vassilev I. Anode-assisted electro-fermentation with Bacillus subtilis under oxygen-limited conditions. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:6. [PMID: 36627716 PMCID: PMC9832610 DOI: 10.1186/s13068-022-02253-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023]
Abstract
BACKGROUND Bacillus subtilis is generally regarded as a ubiquitous facultative anaerobe. Oxygen is the major electron acceptor of B. subtilis, and when oxygen is absent, B. subtilis can donate electrons to nitrate or perform fermentation. An anode electrode can also be used by microorganisms as the electron sink in systems called anodic electro-fermentation. The facultative anaerobic character of B. subtilis makes it an excellent candidate to explore with different electron acceptors, such as an anode. This study aimed to optimise industrial aerobic bioprocesses using alternative electron acceptors. In particular, different end product spectrum of B. subtilis with various electron acceptors, including anode from the electro-fermentation system, was investigated. RESULTS B. subtilis was grown using three electron acceptors, i.e. oxygen, nitrate and anode (poised at a potential of 0.7 V vs. standard hydrogen electrode). The results showed oxygen had a crucial role for cells to remain metabolically active. When nitrate or anode was applied as the sole electron acceptor anaerobically, immediate cell lysis and limited glucose consumption were observed. In anode-assisted electro-fermentation with a limited aeration rate, acetoin, as the main end product showed the highest yield of 0.78 ± 0.04 molproduct/molglucose, two-fold higher than without poised potential (0.39 ± 0.08 molproduct/molglucose). CONCLUSIONS Oxygen controls B. subtilis biomass growth, alternative electron acceptors utilisation and metabolites formation. Limited oxygen/air supply enabled the bacteria to donate excess electrons to nitrate or anode, leading to steered product spectrum. The anode-assisted electro-fermentation showed its potential to boost acetoin production for future industrial biotechnology applications.
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Affiliation(s)
- Yu Sun
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Marika Kokko
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Igor Vassilev
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
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Zabed HM, Akter S, Rupani PF, Akor J, Zhang Y, Zhao M, Zhang C, Ragauskas AJ, Qi X. Biocatalytic gateway to convert glycerol into 3-hydroxypropionic acid in waste-based biorefineries: Fundamentals, limitations, and potential research strategies. Biotechnol Adv 2023; 62:108075. [PMID: 36502965 DOI: 10.1016/j.biotechadv.2022.108075] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/02/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022]
Abstract
Microbial conversion of bioenergy-derived waste glycerol into value-added chemicals has emerged as an important bioprocessing technology due to its eco-friendliness, feasible technoeconomics, and potential to provide sustainability in biodiesel and bioethanol production. Glycerol is an abundant liquid waste from bioenergy plants with a projected volume of 6 million tons by 2025, accounting for about 10% of biodiesel and 2.5% of bioethanol yields. 3-Hydroxypropionic acid (3-HP) is a major product of glycerol bioconversion, which is the third largest biobased platform compound with expected market size and value of 3.6 million tons/year and USD 10 billion/year, respectively. Despite these biorefinery values, 3-HP biosynthesis from glycerol is still at an immature stage of commercial exploitation. The main challenges behind this immaturity are the toxic effects of 3-HPA on cells, the distribution of carbon flux to undesirable pathways, low tolerance of cells to glycerol and 3-HP, co-factor dependence of enzymes, low enzyme activity and stability, and the problems of substrate inhibition and specificity of enzymes. To address these challenges, it is necessary to understand the fundamentals of glycerol bioconversion and 3-HP production in terms of metabolic pathways, related enzymes, cell factories, midstream process configurations, and downstream 3-HP recovery, as discussed in this review critically and comprehensively. It is equally important to know the current challenges and limitations in 3-HP production, which are discussed in detail along with recent research efforts and remaining gaps. Finally, possible research strategies are outlined considering the recent technological advances in microbial biosynthesis, aiming to attract further research efforts to achieve a sustainable and industrially exploitable 3-HP production technology. By discussing the use of advanced tools and strategies to overcome the existing challenges in 3-HP biosynthesis, this review will attract researchers from many other similar biosynthesis technologies and provide a common gateway for their further development.
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Affiliation(s)
- Hossain M Zabed
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Suely Akter
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Parveen Fatemah Rupani
- Department of Chemical Engineering, Ku Luven, Jan De Nayerlaan 5, 2860 Sint-Katelijne-Waver, Belgium
| | - Joseph Akor
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Yufei Zhang
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Mei Zhao
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Cunsheng Zhang
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996, USA; UTK-ORNL Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Xianghui Qi
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China; School of Life Sciences, Guangzhou University, Guangzhou 510,006, Guangdong Province, China.
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10
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Sriram S, Wong JWC, Pradhan N. Recent advances in electro-fermentation technology: A novel approach towards balanced fermentation. BIORESOURCE TECHNOLOGY 2022; 360:127637. [PMID: 35853590 DOI: 10.1016/j.biortech.2022.127637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Biotransformation of organic substrates via acidogenic fermentation (AF) to high-value products such as C1-C6 carboxylic acids and alcohol serves as platform chemicals for various industrial applications. However, the AF technology suffers from low product titers due to thermodynamic constraints. Recent studies suggest that augmenting AF redox potential can regulate the metabolic pathway and provide seamless electron flow by lowering the activation energy barrier, thus positively influencing the substrate utilization rate, product yield, and speciation. Hence, the augmented AF system with an exogenous electricity supply is termed as electro-fermentation (EF), which has enormous potential to strengthen the fermentation technology domain. Therefore, this critical review systematically discusses the current understanding of EF with a special focus on the extracellular electron transfer mechanism of electroactive bacteria and provides perspectives and research gaps to further improve the technology for green chemical synthesis, sustainable waste management, and circular bio-economy.
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Affiliation(s)
- Saranya Sriram
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Hong Kong, SAR
| | - Jonathan W C Wong
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Hong Kong, SAR; Institute of Bioresource and Agriculture, Hong Kong Baptist University, Kowloon Tong, Hong Kong, SAR.
| | - Nirakar Pradhan
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Hong Kong, SAR; Institute of Bioresource and Agriculture, Hong Kong Baptist University, Kowloon Tong, Hong Kong, SAR.
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11
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Baek J, Kim C, Eun Song Y, Kong DS, Mutyala S, Seol EH, Kim JR. Bioelectrochemical metabolic regulation of a heterologously expressed glycerol reductive pathway in E. coli BL21(DE3). Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.141260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Gemünde A, Lai B, Pause L, Krömer J, Holtmann D. Redox mediators in microbial electrochemical systems. ChemElectroChem 2022. [DOI: 10.1002/celc.202200216] [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]
Affiliation(s)
- André Gemünde
- Technische Hochschule Mittelhessen Institute of Bioprocess Engineering and Pharmaceutical Technology Wiesenstraße 14 35390 Gießen GERMANY
| | - Bin Lai
- Helmholtz Centre for Environmental Research UFZ Department of Environmental Microbiology: Helmholtz-Zentrum fur Umweltforschung UFZ Abteilung Umweltmikrobiologie Systems Biotechnology 04318 Leipzig GERMANY
| | - Laura Pause
- Helmholtz Centre for Environmental Research UFZ Environmental Engineering and Biotechnology Research Unit: Helmholtz-Zentrum fur Umweltforschung UFZ Themenbereich Umwelt- und Biotechnologie Systems Biotechnology 04318 Leipzig GERMANY
| | - Jens Krömer
- Helmholtz Centre for Environmental Research UFZ Environmental Engineering and Biotechnology Research Unit: Helmholtz-Zentrum fur Umweltforschung UFZ Themenbereich Umwelt- und Biotechnologie Systems Biotechnology 04318 Leipzig GERMANY
| | - Dirk Holtmann
- Technische Hochschule Mittelhessen IBPT Wiesenstrasse 14 35390 Giessen GERMANY
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13
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Virdis B, Hoelzle R, Marchetti A, Boto ST, Rosenbaum MA, Blasco-Gómez R, Puig S, Freguia S, Villano M. Electro-fermentation: Sustainable bioproductions steered by electricity. Biotechnol Adv 2022; 59:107950. [PMID: 35364226 DOI: 10.1016/j.biotechadv.2022.107950] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 02/22/2022] [Accepted: 03/24/2022] [Indexed: 01/06/2023]
Abstract
The market of biobased products obtainable via fermentation processes is steadily increasing over the past few years, driven by the need to create a decarbonized economy. To date, industrial fermentation (IF) employs either pure or mixed microbial cultures (MMC) whereby the type of the microbial catalysts and the used feedstock affect metabolic pathways and, in turn, the type of product(s) generated. In many cases, especially when dealing with MMC, the economic viability of IF is hindered by factors such as the low attained product titer and selectivity, which ultimately challenge the downstream recovery and purification steps. In this context, electro-fermentation (EF) represents an innovative approach, based on the use of a polarized electrode interface to trigger changes in the rate, yield, titer or product distribution deriving from traditional fermentation processes. In principle, the electrode in EF can act as an electron acceptor (i.e., anodic electro-fermentation, AEF) or donor (i.e., cathodic electro-fermentation, CEF), or simply as a mean to control the oxidation-reduction potential of the fermentation broth. However, the molecular and biochemical basis underlying the EF process are still largely unknown. This review paper provides a comprehensive overview of recent literature studies including both AEF and CEF examples with either pure or mixed microbial cultures. A critical analysis of biochemical, microbiological, and engineering aspects which presently hamper the transition of the EF technology from the laboratory to the market is also presented.
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Affiliation(s)
- Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert Hoelzle
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angela Marchetti
- Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Santiago T Boto
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), 07743 Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), 07743 Jena, Germany
| | - Ramiro Blasco-Gómez
- LEQUIA, Institute of the Environment, University of Girona, Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Sebastià Puig
- LEQUIA, Institute of the Environment, University of Girona, Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Stefano Freguia
- Department of Chemical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Marianna Villano
- Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
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14
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Xu B, Li Z, Jiang Y, Chen M, Chen B, Xin F, Dong W, Jiang M. Recent advances in the improvement of bi-directional electron transfer between abiotic/biotic interfaces in electron-assisted biosynthesis system. Biotechnol Adv 2021; 54:107810. [PMID: 34333092 DOI: 10.1016/j.biotechadv.2021.107810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 07/06/2021] [Accepted: 07/26/2021] [Indexed: 12/18/2022]
Abstract
As an important biosynthesis technology, electron-assisted biosynthesis (EABS) system can utilize exogenous electrons to regulate the metabolic network of microorganisms, realizing the biosynthesis of high value-added chemicals and CO2 fixation. Electrons play crucial roles as the energy carriers in the EABS process. In fact, efficient interfacial electron transfer (ET) is the decisive factor to realize the rapid energy exchange, thus stimulating the biosynthesis of target metabolic products. However, due to the interfacial resistance of ET between the abiotic solid electrode and biotic microbial cells, the low efficiency of interfacial ET has become a major bottleneck, further limiting the practical application of EABS system. As the cell membrane is insulated, even the cell membrane embedded electron conduit (no matter cytochromes or channel protein for shuttle transferring) to increase the cell membrane conductivity, the ET between membrane electron conduit and electrode surface is kinetically restricted. In this review, the pathway of bi-directional interfacial ET in EABS system was summarized. Furthermore, we reviewed representative milestones and advances in both the anode outward interfacial ET (from organism to electrode) and cathode inward interfacial ET (from electrode to organism). Here, new insights from the perspectives of material science and synthetic biology were also proposed, which were expected to provide some innovative opinions and ideas for the following in-depth studies.
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Affiliation(s)
- Bin Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Zhe Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Yujia Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Minjiao Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China
| | - Boryann Chen
- Department of Chemical and Materials Engineering, National I-Lan University, I-Lan 26047, Taiwan
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, PR China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, PR China.
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, PR China.
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15
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Kong DS, Kim C, Song YE, Baek J, Im HS, Kim JR. Zero-valent iron driven bioconversion of glycerol to 1,3-propanediol using Klebsiella pneumoniae L17. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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16
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Zhang Y, Li J, Meng J, Wang X. A cathodic electro-fermentation system for enhancing butyric acid production from rice straw with a mixed culture. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 767:145011. [PMID: 33636772 DOI: 10.1016/j.scitotenv.2021.145011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/24/2020] [Accepted: 12/29/2020] [Indexed: 06/12/2023]
Abstract
Bio-electrochemical system (BES) emerges as a versatile approach to handling environmental problems with the harvest of sustainable energy and value-added chemicals. To enhance the butyric acid production from rice straw, microbial fuel cell (MFC) and cathodic electro-fermentation (CEF) systems were constructed in this study. Inoculated with the same mixed culture, fermentative butyric acid production efficiency of the two BESs were evaluated with/without neutral red (NR) as electron mediator, respectively. It was found that the butyric acid fermentation efficiency in the MFC system was inefficient. While, the CEF system presented an evident positive effect on butyric acid production. The production and specific yield of butyric acid in the CEF system reached 5.54 g/L and 0.41 g/g, higher than that in the open circuit (OC) system by 17.37% and 28.13%, respectively. Mass percentage of butyric acid in the produced total volatile fatty acids (VFAs) was also increased from 44.74% to 52.76%. The addition of NR had no positive effect on the butyric acid production, due to the low contribution of electric current to the end-products. With the cathode potential of -0.80 V (vs Ag/AgCl), relative abundance of the butyric acid fermenting bacteria (Clostridium cluster IV and cluster XIVa) in the microbial mixture was increased from 20.25% in the OC system to 33.61% in the CEF system. This research work not only presents a novel method for enhancing butyric acid production by rice straw fermentation, but also aids an understanding of the fermentation mechanism in CEF systems.
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Affiliation(s)
- Yafei Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China
| | - Jianzheng Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China
| | - Jia Meng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China.
| | - Xin Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China
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17
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Vassilev I, Averesch NJH, Ledezma P, Kokko M. Anodic electro-fermentation: Empowering anaerobic production processes via anodic respiration. Biotechnol Adv 2021; 48:107728. [PMID: 33705913 DOI: 10.1016/j.biotechadv.2021.107728] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/31/2021] [Accepted: 03/03/2021] [Indexed: 11/24/2022]
Abstract
In nature as well as in industrial microbiology, all microorganisms need to achieve redox balance. Their redox state and energy conservation highly depend on the availability of a terminal electron acceptor, for example oxygen in aerobic production processes. Under anaerobic conditions in the absence of an electron acceptor, redox balance is achieved via the production of reduced carbon-compounds (fermentation). An alternative strategy to artificially stabilize microbial redox and energy state is the use of anodic electro-fermentation (AEF). This emerging biotechnology empowers respiration under anaerobic conditions using the anode of a bioelectrochemical system as an undepletable terminal electron acceptor. Electrochemical control of redox metabolism and energy conservation via AEF can steer the carbon metabolism towards a product of interest and avoid the need for continuous and cost-inefficient supply of oxygen as well as the production of mixed reduced by-products, as is the case in aerobic production and fermentation processes, respectively. The great challenge for AEF is to establish efficient extracellular electron transfer (EET) from the microbe to the anode and link it to central carbon metabolism to enhance the synthesis of a target product. This article reviews the advantages and challenges of AEF, EET mechanisms, microbial energy gain, and discusses the rational choice of substrate-product couple as well as the choice of microbial catalyst. Besides, it discusses the potential of the industrial model-organism Bacillus subtilis as a promising candidate for AEF, which has not been yet considered for such an application. This prospective review contributes to a better understanding of how industrial microbiology can benefit from AEF and analyses key-factors required to successfully implement AEF processes. Overall, this work aims to advance the young research field especially by critically revisiting the fundamental aspects of AEF.
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Affiliation(s)
- Igor Vassilev
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
| | - Nils J H Averesch
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States.
| | - Pablo Ledezma
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia.
| | - Marika Kokko
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
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18
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Isipato M, Dessì P, Sánchez C, Mills S, Ijaz UZ, Asunis F, Spiga D, De Gioannis G, Mascia M, Collins G, Muntoni A, Lens PNL. Propionate Production by Bioelectrochemically-Assisted Lactate Fermentation and Simultaneous CO 2 Recycling. Front Microbiol 2021; 11:599438. [PMID: 33384675 PMCID: PMC7769879 DOI: 10.3389/fmicb.2020.599438] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/23/2020] [Indexed: 11/17/2022] Open
Abstract
Production of volatile fatty acids (VFAs), fundamental building blocks for the chemical industry, depends on fossil fuels but organic waste is an emerging alternative substrate. Lactate produced from sugar-containing waste streams can be further processed to VFAs. In this study, electrofermentation (EF) in a two-chamber cell is proposed to enhance propionate production via lactate fermentation. At an initial pH of 5, an applied potential of −1 V vs. Ag/AgCl favored propionate production over butyrate from 20 mM lactate (with respect to non-electrochemical control incubations), due to the pH buffering effect of the cathode electrode, with production rates up to 5.9 mM d–1 (0.44 g L–1 d–1). Microbial community analysis confirmed the enrichment of propionate-producing microorganisms, such as Tyzzerella sp. and Propionibacterium sp. Organisms commonly found in microbial electrosynthesis reactors, such as Desulfovibrio sp. and Acetobacterium sp., were also abundant at the cathode, indicating their involvement in recycling CO2 produced by lactate fermentation into acetate, as confirmed by stoichiometric calculations. Propionate was the main product of lactate fermentation at substrate concentrations up to 150 mM, with a highest production rate of 12.9 mM d–1 (0.96 g L–1 d–1) and a yield of 0.48 mol mol–1 lactate consumed. Furthermore, as high as 81% of the lactate consumed (in terms of carbon) was recovered as soluble product, highlighting the potential for EF application with high-carbon waste streams, such as cheese whey or other food wastes. In summary, EF can be applied to control lactate fermentation toward propionate production and to recycle the resulting CO2 into acetate, increasing the VFA yield and avoiding carbon emissions and addition of chemicals for pH control.
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Affiliation(s)
- Marco Isipato
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.,Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Paolo Dessì
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Carlos Sánchez
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Simon Mills
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Umer Z Ijaz
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Fabiano Asunis
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy
| | - Daniela Spiga
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy
| | - Giorgia De Gioannis
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.,IGAG-CNR, Environmental Geology and Geoengineering Institute of the National Research Council-Piazza D'Armi 1, Cagliari, Italy
| | - Michele Mascia
- Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Università degli Studi di Cagliari, Cagliari, Italy
| | - Gavin Collins
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Aldo Muntoni
- Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Cagliari, Italy.,IGAG-CNR, Environmental Geology and Geoengineering Institute of the National Research Council-Piazza D'Armi 1, Cagliari, Italy
| | - Piet N L Lens
- Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland Galway, Galway, Ireland
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19
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Song YE, Kim C, Li S, Baek J, Seol E, Park C, Na JG, Lee J, Oh YK, Kim JR. Supply of proton enhances CO electrosynthesis for acetate and volatile fatty acid productions. BIORESOURCE TECHNOLOGY 2021; 320:124245. [PMID: 33126131 DOI: 10.1016/j.biortech.2020.124245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
The microbial electrosynthesis is a platform to supply protons and electrons to improve the conversion efficiency and production rate for the valorization of C1 gas. This study examined proton migration and electron transfer of the electrode and microbe by using various external parameters in the electrosynthesis of CO. The CO electrosynthesis achieved almost double of coulombic efficiency than the conventional CO2 electrosynthesis. The maximum volumetric acetate production rate was 0.71 g/L/day in the BES, which was 2-6 times higher than reported elsewhere. These results show that the efficient proton migration and electron transfer can enhance the productivity and conversion efficiency of the biological CO conversion in a bioelectrochemical system.
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Affiliation(s)
- Young Eun Song
- School of Chemical Engineering, Pusan National University, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Changman Kim
- Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA
| | - Shuwei Li
- School of Chemical Engineering, Pusan National University, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Jiyun Baek
- School of Chemical Engineering, Pusan National University, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Eunhee Seol
- School of Chemical Engineering, Pusan National University, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Chulhwan Park
- Department of Chemical Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul 01897, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul 04107, Republic of Korea
| | - Jinwon Lee
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul 04107, Republic of Korea
| | - You-Kwan Oh
- School of Chemical Engineering, Pusan National University, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Jung Rae Kim
- School of Chemical Engineering, Pusan National University, Geumjeong-Gu, Busan 46241, Republic of Korea.
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20
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Stewart KN, Domaille DW. Enhancing Biosynthesis and Manipulating Flux in Whole Cells with Abiotic Catalysis. Chembiochem 2020; 22:469-477. [PMID: 32851745 DOI: 10.1002/cbic.202000458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/20/2020] [Indexed: 01/08/2023]
Abstract
Metabolic engineering uses genetic strategies to drive flux through desired pathways. Recent work with electrochemical, photochemical, and chemocatalytic setups has revealed that these systems can also expand metabolic pathways and manipulate flux in whole cells. Electrochemical systems add or remove electrons from metabolic pathways to direct flux to more- or less-reduced products. Photochemical systems act as synthetic light-harvesting complexes and yield artificial photosynthetic organisms. Biocompatible chemocatalysis increases product scope, streamlines syntheses, and yields single-flask processes to deliver products that would be challenging to synthesize through biosynthetic means alone. Here, we exclusively highlight systems that combine abiotic systems with living whole cells, taking particular note of strategies that enable the merger of these typically disparate systems.
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Affiliation(s)
- Kelsey N Stewart
- Department of Chemistry, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80403, USA
| | - Dylan W Domaille
- Department of Chemistry, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80403, USA
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21
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Gong Z, Yu H, Zhang J, Li F, Song H. Microbial electro-fermentation for synthesis of chemicals and biofuels driven by bi-directional extracellular electron transfer. Synth Syst Biotechnol 2020; 5:304-313. [PMID: 32995586 PMCID: PMC7490822 DOI: 10.1016/j.synbio.2020.08.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/23/2020] [Accepted: 08/25/2020] [Indexed: 11/16/2022] Open
Abstract
Electroactive bacteria could perform bi-directional extracellular electron transfer (EET) to exchange electrons and energy with extracellular environments, thus playing a central role in microbial electro-fermentation (EF) process. Unbalanced fermentation and microbial electrosynthesis are the main pathways to produce value-added chemicals and biofuels. However, the low efficiency of the bi-directional EET is a dominating bottleneck in these processes. In this review, we firstly demonstrate the main bi-directional EET mechanisms during EF, including the direct EET and the shuttle-mediated EET. Then, we review representative milestones and progresses in unbalanced fermentation via anode outward EET and microbial electrosynthesis via inward EET based on these two EET mechanisms in detail. Furthermore, we summarize the main synthetic biology strategies in improving the bi-directional EET and target products synthesis, thus to enhance the efficiencies in unbalanced fermentation and microbial electrosynthesis. Lastly, a perspective on the applications of microbial electro-fermentation is provided.
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Affiliation(s)
- Ziying Gong
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Huan Yu
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Junqi Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Feng Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
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22
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Philipp LA, Edel M, Gescher J. Genetic engineering for enhanced productivity in bioelectrochemical systems. ADVANCES IN APPLIED MICROBIOLOGY 2020; 111:1-31. [PMID: 32446410 DOI: 10.1016/bs.aambs.2020.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A shift from petrochemical processes toward a bio-based economy is one of the most advocated developments for a sustainable future. To achieve this will require the biotechnological production of platform chemicals that can be further processed by chemical engineering. Bioelectrochemical systems (BESs) are a novel tool within the biotechnology field. In BESs, microbes serve as biocatalysts for the production of biofuels and value-added compounds, as well as for the production of electricity. Although the general feasibility of bioelectrochemical processes has been demonstrated in recent years, much research has been conducted to develop biocatalysts better suited to meet industrial demands. Initially, mainly natural exoelectrogenic organisms were investigated for their performance in BESs. Driven by possibilities of recent developments in genetic engineering and synthetic biology, the spectrum of microbial catalysts and their versatility (substrate and product range) have expanded significantly. Despite these developments, there is still a tremendous gap between currently achievable space-time yields and current densities on the one hand and the theoretical limits of BESs on the other. It will be necessary to move the performance of the biocatalysts closer to the theoretical possibilities in order to establish viable production routines. This review summarizes the status quo of engineering microbial biocatalysts for anode-applications with high space-time yields. Furthermore, we will address some of the theoretical limitations of these processes exemplarily and discuss which of the present strategies might be combined to achieve highly synergistic effects and, thus, meet industrial demands.
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Affiliation(s)
- Laura-Alina Philipp
- Karlsruhe Institute of Technology, Institute for Applied Biosciences-Department of Applied Biology, Karlsruhe, Germany
| | - Miriam Edel
- Karlsruhe Institute of Technology, Institute for Applied Biosciences-Department of Applied Biology, Karlsruhe, Germany
| | - Johannes Gescher
- Karlsruhe Institute of Technology, Institute for Applied Biosciences-Department of Applied Biology, Karlsruhe, Germany; Karlsruhe Institute of Technology, Institute for Biological Interfaces, Eggenstein-Leopoldshafen, Germany.
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23
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Bioelectrosynthetic Conversion of CO2 Using Different Redox Mediators: Electron and Carbon Balances in a Bioelectrochemical System. ENERGIES 2020. [DOI: 10.3390/en13102572] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Microbial electrosynthesis (MES) systems can convert CO2 to acetate and other value-added chemicals using electricity as the reducing power. Several electrochemically active redox mediators can enhance interfacial electron transport between bacteria and the electrode in MES systems. In this study, different redox mediators, such as neutral red (NR), 2-hydroxy-1,4-naphthoquinone (HNQ), and hydroquinone (HQ), were compared to facilitate an MES-based CO2 reduction reaction on the cathode. The mediators, NR and HNQ, improved acetate production from CO2 (165 mM and 161 mM, respectively) compared to the control (without a mediator = 149 mM), whereas HQ showed lower acetate production (115 mM). On the other hand, when mediators were used, the electron and carbon recovery efficiency decreased because of the presence of bioelectrochemical reduction pathways other than acetate production. Cyclic voltammetry of an MES with such mediators revealed CO2 reduction to acetate on the cathode surface. These results suggest that the addition of mediators to MES can improve CO2 conversion to acetate with further optimization in an operating strategy of electrosynthesis processes.
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24
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Kim C, Lee JH, Baek J, Kong DS, Na JG, Lee J, Sundstrom E, Park S, Kim JR. Small Current but Highly Productive Synthesis of 1,3-Propanediol from Glycerol by an Electrode-Driven Metabolic Shift in Klebsiella pneumoniae L17. CHEMSUSCHEM 2020; 13:564-573. [PMID: 31808287 DOI: 10.1002/cssc.201902928] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/02/2019] [Indexed: 06/10/2023]
Abstract
Electrofermentation actively regulates the bacterial redox state, which is essential for bioconversion and has been highlighted as an effective method for further improvements of the productivity of either reduced or oxidized platform chemicals. 1,3-Propanediol (1,3-PDO) is an industrial value-added chemical that can be produced from glycerol fermentation. The bioconversion of 1,3-PDO from glycerol requires additional reducing energy under anoxic conditions. The cathode-based conversion of glycerol to 1,3-PDO with various electron shuttles (2-hydroxy-1,4-naphthoquinone, neutral red, and hydroquinone) using Klebsiella pneumoniae L17 was investigated. The externally poised potential of -0.9 V vs. Ag/AgCl to the cathode increased 1,3-PDO (35.5±3.1 mm) production if 100 μm neutral red was used compared with non-bioelectrochemical system fermentation (23.7±2.4 mm). Stoichiometric metabolic flux and transcriptional analysis indicated a shift in the carbon flux toward the glycerol reductive pathway. The homologous overexpression of glycerol dehydratase (DhaB) and 1,3-PDO oxidoreductase (DhaT) enzymes synergistically enhanced 1,3-PDO conversion (39.3±0.8 mm) under cathode-driven fermentation. Interestingly, a small current uptake (0.23 mmol of electrons) caused significant metabolic flux changes with a concomitant increase in 1,3-PDO production. This suggests that both an increase in 1,3-PDO production and regulation of the cellular metabolic pathway are feasible by electrode-driven control in cathodic electrofermentation.
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Affiliation(s)
- Changman Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 609-735, Republic of Korea
- Present Address: Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
| | - Jae Hyeon Lee
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 609-735, Republic of Korea
| | - Jiyun Baek
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 609-735, Republic of Korea
| | - Da Seul Kong
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 609-735, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul, 04107, Republic of Korea
| | - Jinwon Lee
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-Ro, Mapo-Gu, Seoul, 04107, Republic of Korea
| | - Eric Sundstrom
- Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
| | - Sunghoon Park
- School of Energy and Chemical Engineering, UNIST, Ulsan, 689-798, Republic of Korea
| | - Jung Rae Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 609-735, Republic of Korea
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Chu N, Liang Q, Jiang Y, Zeng RJ. Microbial electrochemical platform for the production of renewable fuels and chemicals. Biosens Bioelectron 2020; 150:111922. [DOI: 10.1016/j.bios.2019.111922] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/23/2019] [Accepted: 11/25/2019] [Indexed: 12/01/2022]
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Jers C, Kalantari A, Garg A, Mijakovic I. Production of 3-Hydroxypropanoic Acid From Glycerol by Metabolically Engineered Bacteria. Front Bioeng Biotechnol 2019; 7:124. [PMID: 31179279 PMCID: PMC6542942 DOI: 10.3389/fbioe.2019.00124] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 05/07/2019] [Indexed: 11/13/2022] Open
Abstract
3-hydroxypropanoic acid (3-HP) is a valuable platform chemical with a high demand in the global market. 3-HP can be produced from various renewable resources. It is used as a precursor in industrial production of a number of chemicals, such as acrylic acid and its many derivatives. In its polymerized form, 3-HP can be used in bioplastic production. Several microbes naturally possess the biosynthetic pathways for production of 3-HP, and a number of these pathways have been introduced in some widely used cell factories, such as Escherichia coli and Saccharomyces cerevisiae. Latest advances in the field of metabolic engineering and synthetic biology have led to more efficient methods for bio-production of 3-HP. These include new approaches for introducing heterologous pathways, precise control of gene expression, rational enzyme engineering, redirecting the carbon flux based on in silico predictions using genome scale metabolic models, as well as optimizing fermentation conditions. Despite the fact that the production of 3-HP has been extensively explored in established industrially relevant cell factories, the current production processes have not yet reached the levels required for industrial exploitation. In this review, we explore the state of the art in 3-HP bio-production, comparing the yields and titers achieved in different microbial cell factories and we discuss possible methodologies that could make the final step toward industrially relevant cell factories.
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Affiliation(s)
- Carsten Jers
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Aida Kalantari
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Abhroop Garg
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Ivan Mijakovic
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.,Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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Isolation of Novel CO Converting Microorganism Using Zero Valent Iron for a Bioelectrochemical System (BES). BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-018-0373-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Kim MY, Kim C, Ainala SK, Bae H, Jeon BH, Park S, Kim JR. Metabolic shift of Klebsiella pneumoniae L17 by electrode-based electron transfer using glycerol in a microbial fuel cell. Bioelectrochemistry 2019; 125:1-7. [DOI: 10.1016/j.bioelechem.2018.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/06/2018] [Accepted: 08/06/2018] [Indexed: 10/28/2022]
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Ishizaki S, Papry RI, Miyake H, Narita Y, Okabe S. Membrane Fouling Potentials of an Exoelectrogenic Fouling-Causing Bacterium Cultured With Different External Electron Acceptors. Front Microbiol 2019; 9:3284. [PMID: 30692973 PMCID: PMC6340052 DOI: 10.3389/fmicb.2018.03284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/17/2018] [Indexed: 01/05/2023] Open
Abstract
Integrated microbial fuel cell (MFC) and membrane bioreactor (MBR) systems are a promising cost-effective and energy-saving technology for wastewater treatment. Membrane fouling is still an important issue of such integrated systems in which aeration (oxygen) is replaced with anode electrodes (anodic respiration). Here, we investigated the effect of culture conditions on the membrane fouling potential of fouling-causing bacteria (FCB). In the present study, Klebsiella quasipneumoniae strain S05, which is an exoelectrogenic FCB isolated from a MBR treating municipal wastewater, was cultured with different external electron acceptors (oxygen, nitrate, and solid-state anode electrode). As results, the fouling potential of S05 was lowest when cultured with anode electrode and highest without any external electron acceptor (p < 0.05, respectively). The composition of soluble microbial products (SMP) and extracellular polymeric substances (EPS) was also dependent on the type of electron acceptor. Protein and biopolymer contents in SMP were highly correlated with the fouling potential (R2 = 0.73 and 0.81, respectively). Both the fouling potential and yield of protein and biopolymer production were significantly mitigated by supplying electron acceptors sufficiently regardless of its types. Taken together, the aeration of MBR could be replaced with solid-state anode electrodes without enhancement of membrane fouling, and the anode electrodes must be placed sufficiently to prevent the dead spaces in the integrated reactor.
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Affiliation(s)
- So Ishizaki
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Rimana Islam Papry
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Hiroshi Miyake
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Yuko Narita
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Satoshi Okabe
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, Sapporo, Japan
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de Fouchécour F, Sánchez-Castañeda AK, Saulou-Bérion C, Spinnler HÉ. Process engineering for microbial production of 3-hydroxypropionic acid. Biotechnol Adv 2018; 36:1207-1222. [DOI: 10.1016/j.biotechadv.2018.03.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 02/23/2018] [Accepted: 03/25/2018] [Indexed: 10/17/2022]
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31
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Lee CR, Kim C, Song YE, Im H, Oh YK, Park S, Kim JR. Co-culture-based biological carbon monoxide conversion by Citrobacter amalonaticus Y19 and Sporomusa ovata via a reducing-equivalent transfer mediator. BIORESOURCE TECHNOLOGY 2018; 259:128-135. [PMID: 29549832 DOI: 10.1016/j.biortech.2018.02.129] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/27/2018] [Accepted: 02/28/2018] [Indexed: 06/08/2023]
Abstract
The biological conversion of carbon monoxide (CO) has been highlighted for the development of a C1 gas biorefinery process. Despite this, the toxicity and low reducing equivalent of CO uptake make biological conversion difficult. The use of synthetic co-cultures is an alternative way of enhancing the performance of CO bioconversion. This study evaluated a synthetic co-culture consisting of Citrobacter amalonaticus Y19 and Sporomusa ovata for acetate production from CO. In this consortium, the CO2 and H2 produced by the water-gas shift reaction of C. amalonaticus Y19, were utilized further by S. ovata. Higher acetate production was achieved in the co-culture system compared to the monoculture counterparts. Furthermore, syntrophic cooperation via various reducing equivalent carriers provided new insights into the synergistic metabolic benefits with a toxic and refractory substrate, such as CO. This study also suggests an appropriate model for examining the syntrophic interaction between microbial species in a mixed community.
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Affiliation(s)
- Cho Rong Lee
- School of Chemical and Biomolecular Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Changman Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Young Eun Song
- School of Chemical and Biomolecular Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Hyeonsung Im
- School of Chemical and Biomolecular Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - You-Kwan Oh
- School of Chemical and Biomolecular Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Sunghoon Park
- School of Energy and Chemical Engineering, UNIST, Ulsan, Republic of Korea
| | - Jung Rae Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea.
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Oh YK, Hwang KR, Kim C, Kim JR, Lee JS. Recent developments and key barriers to advanced biofuels: A short review. BIORESOURCE TECHNOLOGY 2018. [PMID: 29523378 DOI: 10.1016/j.biortech.2018.02.089] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Biofuels are regarded as one of the most viable options for reduction of CO2 emissions in the transport sector. However, conventional plant-based biofuels (e.g., biodiesel, bioethanol)'s share of total transportation-fuel consumption in 2016 was very low, about 4%, due to several major limitations including shortage of raw materials, low CO2 mitigation effect, blending wall, and poor cost competitiveness. Advanced biofuels such as drop-in, microalgal, and electro biofuels, especially from inedible biomass, are considered to be a promising solution to the problem of how to cope with the growing biofuel demand. In this paper, recent developments in oxy-free hydrocarbon conversion via catalytic deoxygenation reactions, the selection of and lipid-content enhancement of oleaginous microalgae, electrochemical biofuel conversion, and the diversification of valuable products from biomass and intermediates are reviewed. The challenges and prospects for future development of eco-friendly and economically advanced biofuel production processes also are outlined herein.
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Affiliation(s)
- You-Kwan Oh
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Kyung-Ran Hwang
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Changman Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jung Rae Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jin-Suk Lee
- Gwangju Bioenergy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Republic of Korea.
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33
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Im CH, Kim C, Song YE, Oh SE, Jeon BH, Kim JR. Electrochemically enhanced microbial CO conversion to volatile fatty acids using neutral red as an electron mediator. CHEMOSPHERE 2018; 191:166-173. [PMID: 29032261 DOI: 10.1016/j.chemosphere.2017.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 09/30/2017] [Accepted: 10/01/2017] [Indexed: 06/07/2023]
Abstract
Conversion of C1 gas feedstock, including carbon monoxide (CO), into useful platform chemicals has attracted considerable interest in industrial biotechnology. Nevertheless, the low conversion yield and/or growth rate of CO-utilizing microbes make it difficult to develop a C1 gas biorefinery process. The Wood-Ljungdahl pathway which utilize CO is a pathway suffered from insufficient electron supply, in which the conversion can be increased further when an additional electron source like carbohydrate or hydrogen is provided. In this study, electrode-based electron transference using a bioelectrochemical system (BES) was examined to compensate for the insufficient reducing equivalent and increase the production of volatile fatty acids. The BES including neutral red (BES-NR), which facilitated electron transfer between bacteria and electrode, was compared with BES without neutral red and open circuit control. The coulombic efficiency based on the current input to the system and the electrons recovered into VFAs, was significantly higher in BES-NR than the control. These results suggest that the carbon electrode provides a platform to regulate the redox balance for improving the bioconversion of CO, and amending the conventional C1 gas fermentation.
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Affiliation(s)
- Chae Ho Im
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Changman Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Young Eun Song
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Sang-Eun Oh
- Department of Biological Environment, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon-do 200-701, Republic of Korea
| | - Byong-Hun Jeon
- Department of Natural Resources and Environmental Engineering, Hanyang University, Seoul 133- 791, Republic of Korea.
| | - Jung Rae Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea.
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