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de Smit SM, van Mameren TD, van Zwet K, van Veelen HPJ, Cristina Gagliano M, Strik DPBTB, Bitter JH. Integration of biocompatible hydrogen evolution catalyst developed from metal-mix solutions with microbial electrosynthesis. Bioelectrochemistry 2024; 158:108724. [PMID: 38714063 DOI: 10.1016/j.bioelechem.2024.108724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/09/2024]
Abstract
Microbial conversion of CO2 to multi-carbon compounds such as acetate and butyrate is a promising valorisation technique. For those reactions, the electrochemical supply of hydrogen to the biocatalyst is a viable approach. Earlier we have shown that trace metals from microbial growth media spontaneously form in situ electro-catalysts for hydrogen evolution. Here, we show biocompatibility with the successful integration of such metal mix-based HER catalyst for immediate start-up of microbial acetogenesis (CO2 to acetate). Also, n-butyrate formation started fast (after twenty days). Hydrogen was always produced in excess, although productivity decreased over the 36 to 50 days, possibly due to metal leaching from the cathode. The HER catalyst boosted microbial productivity in a two-step microbial community bioprocess: acetogenesis by a BRH-c20a strain and acetate elongation to n-butyrate by Clostridium sensu stricto 12 (related) species. These findings provide new routes to integrate electro-catalysts and micro-organisms showing respectively bio and electrochemical compatibility.
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Affiliation(s)
- Sanne M de Smit
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands; Biobased Chemistry and Technology, Wageningen University and Research, Wageningen, The Netherlands
| | - Thomas D van Mameren
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands
| | - Koen van Zwet
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - M Cristina Gagliano
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - David P B T B Strik
- Environmental Technology, Wageningen University and Research, Wageningen, The Netherlands.
| | - Johannes H Bitter
- Biobased Chemistry and Technology, Wageningen University and Research, Wageningen, The Netherlands.
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2
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Ehsaan M, Yoo M, Kuit W, Foulquier C, Soucaille P, Minton NP. Chromosomal integration of the pSOL1 megaplasmid of Clostridium acetobutylicum for continuous and stable advanced biofuels production. Nat Microbiol 2024; 9:1655-1660. [PMID: 38877224 PMCID: PMC11222136 DOI: 10.1038/s41564-024-01714-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 04/24/2024] [Indexed: 06/16/2024]
Abstract
Biofuel production by Clostridium acetobutylicum is compromised by strain degeneration due to loss of its pSOL1 megaplasmid. Here we used engineering biology to stably integrate pSOL1 into the chromosome together with a synthetic isopropanol pathway. In a membrane bioreactor continuously fed with glucose mineral medium, the final strain produced advanced biofuels, n-butanol and isopropanol, at high yield (0.31 g g-1), titre (15.4 g l-1) and productivity (15.5 g l-1 h-1) without degeneration.
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Affiliation(s)
- Muhammad Ehsaan
- BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Minyeong Yoo
- BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Wouter Kuit
- BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Céline Foulquier
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
| | - Philippe Soucaille
- BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, UK.
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France.
| | - Nigel P Minton
- BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, Biodiscovery Institute, University of Nottingham, Nottingham, UK
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3
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Schwarz I, Angelina A, Hambrock P, Weuster-Botz D. Simultaneous Formate and Syngas Conversion Boosts Growth and Product Formation by Clostridium ragsdalei. Molecules 2024; 29:2661. [PMID: 38893534 PMCID: PMC11174074 DOI: 10.3390/molecules29112661] [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: 04/19/2024] [Revised: 05/28/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Electrocatalytic CO2 reduction to CO and formate can be coupled to gas fermentation with anaerobic microorganisms. In combination with a competing hydrogen evolution reaction in the cathode in aqueous medium, the in situ, electrocatalytic produced syngas components can be converted by an acetogenic bacterium, such as Clostridium ragsdalei, into acetate, ethanol, and 2,3-butanediol. In order to study the simultaneous conversion of CO, CO2, and formate together with H2 with C. ragsdalei, fed-batch processes were conducted with continuous gassing using a fully controlled stirred tank bioreactor. Formate was added continuously, and various initial CO partial pressures (pCO0) were applied. C. ragsdalei utilized CO as the favored substrate for growth and product formation, but below a partial pressure of 30 mbar CO in the bioreactor, a simultaneous CO2/H2 conversion was observed. Formate supplementation enabled 20-50% higher growth rates independent of the partial pressure of CO and improved the acetate and 2,3-butanediol production. Finally, the reaction conditions were identified, allowing the parallel CO, CO2, formate, and H2 consumption with C. ragsdalei at a limiting CO partial pressure below 30 mbar, pH 5.5, n = 1200 min-1, and T = 32 °C. Thus, improved carbon and electron conversion is possible to establish efficient and sustainable processes with acetogenic bacteria, as shown in the example of C. ragsdalei.
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Affiliation(s)
| | | | | | - Dirk Weuster-Botz
- Chair of Biochemical Engineering, School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, Germany; (I.S.)
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4
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Li K, Zhang X, Li C, Liang YC, Zhao XQ, Liu CG, Sinskey AJ, Bai FW. Systems metabolic engineering of Corynebacterium glutamicum to assimilate formic acid for biomass accumulation and succinic acid production. BIORESOURCE TECHNOLOGY 2024; 402:130774. [PMID: 38701983 DOI: 10.1016/j.biortech.2024.130774] [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: 01/07/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024]
Abstract
Formate as an ideal mediator between the physicochemical and biological realms can be obtained from electrochemical reduction of CO2 and used to produce bio-chemicals. Yet, limitations arise when employing natural formate-utilizing microorganisms due to restricted product range and low biomass yield. This study presents a breakthrough: engineered Corynebacterium glutamicum strains (L2-L4) through modular engineering. L2 incorporates the formate-tetrahydrofolate cycle and reverse glycine cleavage pathway, L3 enhances NAD(P)H regeneration, and L4 reinforces metabolic flux. Metabolic modeling elucidates C1 assimilation, guiding strain optimization for co-fermentation of formate and glucose. Strain L4 achieves an OD600 of 0.5 and produces 0.6 g/L succinic acid. 13C-labeled formate confirms C1 assimilation, and further laboratory evolution yields 1.3 g/L succinic acid. This study showcases a successful model for biologically assimilating formate in C. glutamicum that could be applied in C1-based biotechnological production, ultimately forming a formate-based bioeconomy.
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Affiliation(s)
- Kai Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xue Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cheng Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Disruptive & Sustainable Technologies for Agricultural Precision, Singapore-MIT Alliance for Research and Technology, Singapore 138602, Singapore
| | - Yu-Cheng Liang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xin-Qing Zhao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chen-Guang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Anthony J Sinskey
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Disruptive & Sustainable Technologies for Agricultural Precision, Singapore-MIT Alliance for Research and Technology, Singapore 138602, Singapore
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Gu X, Sun J, Wang T, Li J, Wang H, Wang J, Wang Y. Comprehensive review of microbial production of medium-chain fatty acids from waste activated sludge and enhancement strategy. BIORESOURCE TECHNOLOGY 2024; 402:130782. [PMID: 38701982 DOI: 10.1016/j.biortech.2024.130782] [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: 03/02/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Microbial production of versatile applicability medium-chain fatty acids (MCFAs) (C6-C10) from waste activated sludge (WAS) provides a pioneering approach for wastewater treatment plants (WWTPs) to achieve carbon recovery. Mounting studies emerged endeavored to promote the MCFAs production from WAS while struggling with limited MCFAs production and selectivity. Herein, this review covers comprehensive introduction of the transformation process from WAS to MCFAs and elaborates the mechanisms for unsatisfactory MCFAs production. The enhancement strategies for biotransformation of WAS to MCFAs was presented. Especially, the robust performance of iron-based materials is highlighted. Furthermore, knowledge gaps are identified to outline future research directions. Recycling MCFAs from WAS presents a promising option for future WAS treatment, with iron-based materials emerging as a key regulatory strategy in advancing the application of WAS-to-MCFAs biotechnology. This review will advance the understanding of MCFAs recovery from WAS and promote sustainable resource management in WWTPs.
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Affiliation(s)
- Xin Gu
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jing Sun
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Tong Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jia Li
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jialin Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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6
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Li Y, Cao M, Gupta VK, Wang Y. Metabolic engineering strategies to enable microbial electrosynthesis utilization of CO 2: recent progress and challenges. Crit Rev Biotechnol 2024; 44:352-372. [PMID: 36775662 DOI: 10.1080/07388551.2023.2167065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 10/17/2022] [Accepted: 12/08/2022] [Indexed: 02/14/2023]
Abstract
Microbial electrosynthesis (MES) is a promising technology that mainly utilizes microbial cells to convert CO2 into value-added chemicals using electrons provided by the cathode. However, the low electron transfer rate is a solid bottleneck hindering the further application of MES. Thus, as an effective strategy, genetic tools play a key role in MES for enhancing the electron transfer rate and diversity of production. We describe a set of genetic strategies based on fundamental characteristics and current successes and discuss their functional mechanisms in driving microbial electrocatalytic reactions to fully comprehend the roles and uses of genetic tools in MES. This paper also analyzes the process of nanomaterial application in extracellular electron transfer (EET). It provides a technique that combines nanomaterials and genetic tools to increase MES efficiency, because nanoparticles have a role in the production of functional genes in EET although genetic tools can subvert MES, it still has issues with difficult transformation and low expression levels. Genetic tools remain one of the most promising future strategies for advancing the MES process despite these challenges.
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Affiliation(s)
- Yixin Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, China
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, China
| | - Vijai Kumar Gupta
- Biorefining and Advanced Materials Research Center, SRUC, Edinburgh, UK
| | - Yuanpeng Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, China
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7
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Wan S, Lai M, Gao X, Zhou M, Yang S, Li Q, Li F, Xia L, Tan Y. Recent progress in engineering Clostridium autoethanogenum to synthesize the biochemicals and biocommodities. Synth Syst Biotechnol 2024; 9:19-25. [PMID: 38205027 PMCID: PMC10776380 DOI: 10.1016/j.synbio.2023.12.001] [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: 09/21/2023] [Revised: 11/15/2023] [Accepted: 12/07/2023] [Indexed: 01/12/2024] Open
Abstract
Excessive mining and utilization fossil fuels has led to drastic environmental consequences, which will contribute to global warming and cause further climate change with severe consequences for the human population. The magnitude of these challenges requires several approaches to develop sustainable alternatives for chemicals and fuels production. In this context, biological processes, mainly microbial fermentation, have gained particular interest. For example, autotrophic gas-fermenting acetogenic bacteria are capable of converting CO, CO2 and H2 into biomass and multiple metabolites through Wood-Ljungdahl pathway, which can be exploited for large-scale fermentation processes to sustainably produce bulk biochemicals and biofuels (e.g. acetate and ethanol) from syngas. Clostridium autoethanogenum is one representative of these chemoautotrophic bacteria and considered as the model for the gas fermentation. Recently, the development of synthetic biology toolbox for this strain has enabled us to study and genetically improve their metabolic capability in gas fermentation. In this review, we will summarize the recent progress involved in the understanding of physiological mechanism and strain engineering for C. autoethanogenum, and provide our perspectives on the future development about the basic biology and engineering biology of this strain.
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Affiliation(s)
- Sai Wan
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China
| | - Mingchi Lai
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China
- School of Life Sciences, Qingdao Agricultural University, Qingdao, 266109, Shandong, China
| | - Xinyu Gao
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, Shandong, China
| | - Mingxin Zhou
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen, 518055, China
- Shenzhen Powered Carbon Biotechnology Co., Ltd, Shenzhen, 518055, China
| | - Song Yang
- School of Life Sciences, Qingdao Agricultural University, Qingdao, 266109, Shandong, China
| | - Qiang Li
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, Shandong, China
| | - Fuli Li
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China
| | - Lin Xia
- Shenzhen Powered Carbon Biotechnology Co., Ltd, Shenzhen, 518055, China
| | - Yang Tan
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, 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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10
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Flaiz M, Poehlein A, Wilhelm W, Mook A, Daniel R, Dürre P, Bengelsdorf FR. Refining and illuminating acetogenic Eubacterium strains for reclassification and metabolic engineering. Microb Cell Fact 2024; 23:24. [PMID: 38233843 PMCID: PMC10795377 DOI: 10.1186/s12934-024-02301-8] [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: 10/27/2023] [Accepted: 01/09/2024] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND The genus Eubacterium is quite diverse and includes several acetogenic strains capable of fermenting C1-substrates into valuable products. Especially, Eubacterium limosum and closely related strains attract attention not only for their capability to ferment C1 gases and liquids, but also due to their ability to produce butyrate. Apart from its well-elucidated metabolism, E. limosum is also genetically accessible, which makes it an interesting candidate to be an industrial biocatalyst. RESULTS In this study, we examined genomic, phylogenetic, and physiologic features of E. limosum and the closest related species E. callanderi as well as E. maltosivorans. We sequenced the genomes of the six Eubacterium strains 'FD' (DSM 3662T), 'Marburg' (DSM 3468), '2A' (DSM 2593), '11A' (DSM 2594), 'G14' (DSM 107592), and '32' (DSM 20517) and subsequently compared these with previously available genomes of the E. limosum type strain (DSM 20543T) as well as the strains 'B2', 'KIST612', 'YI' (DSM 105863T), and 'SA11'. This comparison revealed a close relationship between all eleven Eubacterium strains, forming three distinct clades: E. limosum, E. callanderi, and E. maltosivorans. Moreover, we identified the gene clusters responsible for methanol utilization as well as genes mediating chain elongation in all analyzed strains. Subsequent growth experiments revealed that strains of all three clades can convert methanol and produce acetate, butyrate, and hexanoate via reverse β-oxidation. Additionally, we used a harmonized electroporation protocol and successfully transformed eight of these Eubacterium strains to enable recombinant plasmid-based expression of the gene encoding the fluorescence-activating and absorption shifting tag (FAST). Engineered Eubacterium strains were verified regarding their FAST-mediated fluorescence at a single-cell level using a flow cytometry approach. Eventually, strains 'FD' (DSM 3662T), '2A' (DSM 2593), '11A' (DSM 2594), and '32' (DSM 20517) were genetically engineered for the first time. CONCLUSION Strains of E. limosum, E. callanderi, and E. maltosivorans are outstanding candidates as biocatalysts for anaerobic C1-substrate conversion into valuable biocommodities. A large variety of strains is genetically accessible using a harmonized electroporation protocol, and FAST can serve as a reliable fluorescent reporter protein to characterize genetically engineered cells. In total eleven strains have been assigned to distinct clades, providing a clear and updated classification. Thus, the description of respective Eubacterium species has been emended, improved, aligned, and is requested to be implemented in respective databases.
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Affiliation(s)
- Maximilian Flaiz
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany.
| | - Anja Poehlein
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University, Göttingen, Germany
| | - Wiebke Wilhelm
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Alexander Mook
- Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University, Göttingen, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Frank R Bengelsdorf
- Institute of Molecular Biology and Biotechnology of Prokaryotes, University of Ulm, Ulm, Germany.
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11
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Kwon HJ, Lee J, Kwon SJ, Lee HS. Development of a genetic engineering toolbox for syngas-utilizing acetogen Clostridium sp. AWRP. Microb Cell Fact 2024; 23:6. [PMID: 38172811 PMCID: PMC10763472 DOI: 10.1186/s12934-023-02272-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Clostridium sp. AWRP (AWRP) is a novel acetogenic bacterium isolated under high partial pressure of carbon monoxide (CO) and can be one of promising candidates for alcohol production from carbon oxides. Compared to model strains such as C. ljungdahlii and C. autoethanogenum, however, genetic manipulation of AWRP has not been established, preventing studies on its physiological characteristics and metabolic engineering. RESULTS We were able to demonstrate the genetic domestication of AWRP, including transformation of shuttle plasmids, promoter characterization, and genome editing. From the conjugation experiment with E. coli S17-1, among the four replicons tested (pCB102, pAMβ1, pIP404, and pIM13), three replicated in AWRP but pCB102 was the only one that could be transferred by electroporation. DNA methylation in E. coli significantly influenced transformation efficiencies in AWRP: the highest transformation efficiencies (102-103 CFU/µg) were achieved with unmethylated plasmid DNA. Determination of strengths of several clostridial promoters enabled the establishment of a CRISPR/Cas12a genome editing system based on Acidaminococcus sp. BV3L6 cas12a gene; interestingly, the commonly used CRISPR/Cas9 system did not work in AWRP, although it expressed the weakest promoter (C. acetobutylicum Pptb) tested. This system was successfully employed for the single gene deletion (xylB and pyrE) and double deletion of two prophage gene clusters. CONCLUSIONS The presented genome editing system allowed us to achieve several genome manipulations, including double deletion of two large prophage groups. The genetic toolbox developed in this study will offer a chance for deeper studies on Clostridium sp. AWRP for syngas fermentation and carbon dioxide (CO2) sequestration.
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Affiliation(s)
- Hae Jun Kwon
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, Republic of Korea
| | - Joungmin Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, Republic of Korea.
| | - Soo Jae Kwon
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, Republic of Korea
- KIOST School, University of Science and Technology, Busan, Republic of Korea
| | - Hyun Sook Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science and Technology, Busan, Republic of Korea.
- KIOST School, University of Science and Technology, Busan, Republic of Korea.
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12
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Jayathilake C, Piyumika G, Nazeer Z, Wijayawardene N, Rajakaruna S, Kumla J, Fernando E. Recent progress in the characterization and application of exo-electrogenic microorganisms. Antonie Van Leeuwenhoek 2024; 117:10. [PMID: 38170279 DOI: 10.1007/s10482-023-01916-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 12/03/2023] [Indexed: 01/05/2024]
Abstract
Exo-electrogenic microorganisms are characterized by their special metabolic capability of transferring metabolic electrons out of their cell, into insoluble external electron acceptors such as iron or manganese oxides and electrodes, or vice versa take up electron from electrodes. Their conventional application is primarily limited to microbial fuel cells for electrical power generation and microbial electrolysis cells for the production of value-added products such as biohydrogen, biomethane and hydrogen peroxide. The utility of exo-electrogenic organisms has expanded into many other applications in recent times. Such examples include microbial desalination cells, microbial electro-synthesis cells producing value-added chemicals such as bio-butanol and their applications in other carbon sequestration technologies. Additionally, electrochemically-active organisms are now beginning to be employed in biosensor applications for environmental monitoring. Additionally, the utility of biocathodes in bio-electrochemical systems is also a novel application in catalyzing the cathodic oxygen reduction reaction to enhance their electrochemical performance. Advances have also been made in the expansion and use of other organisms such as the usage of photosynthetic microorganisms for the fabrication of self-sustained bio-electrochemical systems. This review attempts to provide a comprehensive picture of the state-of the art of exo-electrogenic organisms and their novel utility in bioelectrochemical systems.
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Affiliation(s)
| | - Gayani Piyumika
- Department of Biology, Rajarata University, Mihintale, 50300, Sri Lanka
| | - Zumaira Nazeer
- Department of Biology, Rajarata University, Mihintale, 50300, Sri Lanka
| | - Nalin Wijayawardene
- Centre for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing, 655011, Yunnan, People's Republic of China
| | | | - Jaturong Kumla
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Eustace Fernando
- Department of Biology, Rajarata University, Mihintale, 50300, Sri Lanka.
- School of Engineering and Science, Department of Civil, Environmental and Ocean Engineering, Stevens Institute of Technology, Charles V. Schaefer, Hoboken, NJ, 07030, USA.
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13
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Re A. Translational efficiency in gas-fermenting bacteria: Adding a new layer of regulation to gene expression in acetogens. iScience 2023; 26:108383. [PMID: 38034355 PMCID: PMC10684804 DOI: 10.1016/j.isci.2023.108383] [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] [Indexed: 12/02/2023] Open
Abstract
Major advances in mastering metabolism of single carbon (C1) gaseous feedstocks in acetogenic microorganisms are primed to fuel the transition toward environmentally sustainable and cost-efficient production schemes of biofuels and value-added biochemicals. Since acetogens grow under autotrophic energy-limited conditions, protein synthesis is expected to be controlled. This survey integrated publicly available RNA sequencing and ribosome profiling studies of several acetogens, providing data on genome-scale transcriptional and translational responses of A. woodii, E. limosum, C. drakei, and C. ljungdahlii to autotrophic and heterotrophic growth conditions. The extent of translational efficiency turned out to vary across key functional modules in acetogens' metabolism. Translational control was confirmed to support stoichiometric protein production in multimeric complexes. Comparing the autotrophic to the heterotrophic growth condition revealed growth-dependent regulation of translational efficiency, pointing at translational buffering as a widespread phenomenon shared by acetogens.
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Affiliation(s)
- Angela Re
- Department of Applied Science and Technology, Politecnico di Torino, 10129 Torino, Italy
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14
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Kottenhahn P, Philipps G, Bunk B, Spröer C, Jennewein S. The Restriction-Modification Systems of Clostridium carboxidivorans P7. Microorganisms 2023; 11:2962. [PMID: 38138106 PMCID: PMC10745947 DOI: 10.3390/microorganisms11122962] [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: 11/07/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
Clostridium carboxidivorans P7 (DSM 15243) is a bacterium that converts syngas (a mixture of CO, H2, and CO2) into hexanol. An optimized and scaled-up industrial process could therefore provide a renewable source of fuels and chemicals while consuming industry waste gases. However, the genetic engineering of this bacterium is hindered by its multiple restriction-modification (RM) systems: the genome of C. carboxidivorans encodes at least ten restriction enzymes and eight methyltransferases (MTases). To gain insight into the complex RM systems of C. carboxidivorans, we analyzed genomic methylation patterns using single-molecule real-time (SMRT) sequencing and bisulfite sequencing. We identified six methylated sequence motifs. To match the methylation sites to the predicted MTases of C. carboxidivorans, we expressed them individually in Escherichia coli for functional characterization. Recognition motifs were identified for all three Type I MTases (CAYNNNNNCTGC/GCAGNNNNNRTG, CCANNNNNNNNTCG/CGANNNNNNNNTGG and GCANNNNNNNTNNCG/CGNNANNNNNNNTGC), two Type II MTases (GATAAT and CRAAAAR), and a single Type III MTase (GAAAT). However, no methylated recognition motif was found for one of the three Type II enzymes. One recognition motif that was methylated in C. carboxidivorans but not in E. coli (AGAAGC) was matched to the remaining Type III MTase through a process of elimination. Understanding these enzymes and the corresponding recognition sites will facilitate the development of genetic tools for C. carboxidivorans that can accelerate the industrial exploitation of this strain.
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Affiliation(s)
- Patrick Kottenhahn
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 52074 Aachen, Germany
- Department of Biology, RWTH Aachen University, 52074 Aachen, Germany
| | - Gabriele Philipps
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 52074 Aachen, Germany
| | - Boyke Bunk
- Department Bioinformatics and Databases, Leibniz Institute DSMZ-German Culture Collection for Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
| | - Cathrin Spröer
- Department Bioinformatics and Databases, Leibniz Institute DSMZ-German Culture Collection for Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
| | - Stefan Jennewein
- Department of Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 52074 Aachen, Germany
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15
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Chen G, Wang R, Sun M, Chen J, Iyobosa E, Zhao J. Carbon dioxide reduction to high-value chemicals in microbial electrosynthesis system: Biological conversion and regulation strategies. CHEMOSPHERE 2023; 344:140251. [PMID: 37769909 DOI: 10.1016/j.chemosphere.2023.140251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
Large emissions of atmospheric carbon dioxide (CO2) are causing climatic and environmental problems. It is crucial to capture and utilize the excess CO2 through diverse methods, among which the microbial electrosynthesis (MES) system has become an attractive and promising technology to mitigate greenhouse effects while reducing CO2 to high-value chemicals. However, the biological conversion and metabolic pathways through microbial catalysis have not been clearly elucidated. This review first introduces the main acetogenic bacteria for CO2 reduction and extracellular electron transfer mechanisms in MES. It then intensively analyzes the CO2 bioconversion pathways and carbon chain elongation processes in MES, together with energy supply and utilization. The factors affecting MES performance, including physical, chemical, and biological aspects, are summarized, and the strategies to promote and regulate bioconversion in MES are explored. Finally, challenges and perspectives concerning microbial electrochemical carbon sequestration are proposed, and suggestions for future research are also provided. This review provides theoretical foundation and technical support for further development and industrial application of MES for CO2 reduction.
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Affiliation(s)
- Gaoxiang Chen
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Rongchang Wang
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China.
| | - Maoxin Sun
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Jie Chen
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Eheneden Iyobosa
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
| | - Jianfu Zhao
- Key Laboratory of Yangtze Aquatic Environment (MOE), College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, Shanghai, PR China
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16
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Treece TR, Pattanayak S, Matson MM, Cepeda MM, Berben LA, Atsumi S. Electrical-biological hybrid system for carbon efficient isobutanol production. Metab Eng 2023; 80:142-150. [PMID: 37739158 DOI: 10.1016/j.ymben.2023.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/04/2023] [Accepted: 09/14/2023] [Indexed: 09/24/2023]
Abstract
We have developed an electrical-biological hybrid system wherein an engineered microorganism consumes electrocatalytically produced formate from CO2 to supplement the bioproduction of isobutanol, a valuable fuel chemical. Biological CO2 sequestration is notoriously slow compared to electrochemical CO2 reduction, while electrochemical methods struggle to generate carbon-carbon bonds which readily form in biological systems. A hybrid system provides a promising method for combining the benefits of both biology and electrochemistry. Previously, Escherichia coli was engineered to assimilate formate and CO2 in central metabolism using the reductive glycine pathway. In this work, we have shown that chemical production in E. coli can benefit from single carbon substrates when equipped with the RGP. By installing the RGP and the isobutanol biosynthetic pathway into E. coli and by further genetic modifications, we have generated a strain of E. coli that can consume formate and produce isobutanol at a yield of >100% of theoretical maximum from glucose. Our results demonstrate that carbon produced from electrocatalytically reduced CO2 can bolster chemical production in E. coli. This study shows that E. coli can be engineered towards carbon efficient methods of chemical production.
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Affiliation(s)
- Tanner R Treece
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA
| | - Santanu Pattanayak
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA
| | - Morgan M Matson
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA
| | - Mateo M Cepeda
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA
| | - Louise A Berben
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA.
| | - Shota Atsumi
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA.
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17
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Velvizhi G, Jacqueline PJ, Shetti NP, K L, Mohanakrishna G, Aminabhavi TM. Emerging trends and advances in valorization of lignocellulosic biomass to biofuels. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118527. [PMID: 37429092 DOI: 10.1016/j.jenvman.2023.118527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/25/2023] [Accepted: 06/25/2023] [Indexed: 07/12/2023]
Abstract
Sustainable technologies pave the way to address future energy demand by converting lignocellulosic biomass into fuels, carbon-neutral materials, and chemicals which might replace fossil fuels. Thermochemical and biochemical technologies are conventional methods that convert biomass into value-added products. To enhance biofuel production, the existing technologies should be upgraded using advanced processes. In this regard, the present review explores the advanced technologies of thermochemical processes such as plasma technology, hydrothermal treatment, microwave-based processing, microbial-catalyzed electrochemical systems, etc. Advanced biochemical technologies such as synthetic metabolic engineering and genomic engineering have led to the development of an effective strategy to produce biofuels. The microwave-plasma-based technique increases the biofuel conversion efficiency by 97% and the genetic engineering strains increase the sugar production by 40%, inferring that the advanced technologies enhances the efficiency. So understanding these processes leads to low-carbon technologies which can solve the global issues on energy security, the greenhouse gases emission, and global warming.
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Affiliation(s)
- G Velvizhi
- CO(2) Research and Green Technology Centre, Vellore Institute of Technology (VIT), Vellore, 632 014, Tamil Nadu, India.
| | - P Jennita Jacqueline
- CO(2) Research and Green Technology Centre, Vellore Institute of Technology (VIT), Vellore, 632 014, Tamil Nadu, India; School of Chemical Engineering, Vellore Institute of Technology (VIT), Vellore, 632 014, Tamil Nadu, India
| | - Nagaraj P Shetti
- Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, 580 031, Karnataka, India
| | - Latha K
- Department of Mathematics, Easwari Engineering College, Chennai, 600 089, Tamil Nadu, India
| | - Gunda Mohanakrishna
- Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, 580 031, Karnataka, India
| | - Tejraj M Aminabhavi
- Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, 580 031, Karnataka, India; School of Engineering, UPES, Bidholi, Dehradun, Uttarakhand 248 007, India.
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18
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Li Y, Luo Q, Su J, Dong G, Cao M, Wang Y. Metabolic regulation of Shewanella oneidensis for microbial electrosynthesis: From extracellular to intracellular. Metab Eng 2023; 80:1-11. [PMID: 37673324 DOI: 10.1016/j.ymben.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/09/2023] [Accepted: 08/27/2023] [Indexed: 09/08/2023]
Abstract
Shewanella oneidensis MR-1 (S. oneidensis MR-1) has been shown to benefit from microbial electrosynthesis (MES) due to its exceptional electron transfer efficiency. In this study, genes involved in both extracellular electron uptake (EEU) and intracellular CO2 conversion processes were examined and regulated to enhance MES performance. The key genes identified for MES in the EEU process were mtrB, mtrC, mtrD, mtrE, omcA and cctA. Overexpression of these genes resulted in 1.5-2.1 times higher formate productivity than that of the wild-type strains (0.63 mmol/(L·μg protein)), as 0.94-1.61 mmol/(L·μg protein). In the intracellular CO2 conversion process, overexpression of the nadE, nadD, nadR, nadV, pncC and petC genes increased formate productivity 1.3-fold-3.4-fold. Moreover, overexpression of the formate dehydrogenase genes fdhA1, fdhB1 and fdhX1 in modified strains led to a 2.3-fold-3.1-fold increase in formate productivity compared to wild-type strains. The co-overexpression of cctA, fdhA1 and nadV in the mutant strain resulted in 5.59 times (3.50 mmol/(L·μg protein)) higher formate productivity than that of the wild-type strains. These findings revealed that electrons of MES derived from the electrode were utilized in the energy module for synthesizing ATP and NADH, followed by the synthesis of formate in formate dehydrogenase by the combinatorial effects of ATP, NADH, electrons and CO2. The results provide new insights into the mechanism of MES in S. oneidensis MR-1 and pave the way for genetic improvements that could facilitate the further application of MES.
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Affiliation(s)
- Yixin Li
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, 361005, China
| | - Qingliu Luo
- College of Light Industry and Food Engineering, Guangxi University, Nanning, 530004, China
| | - Jiaying Su
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, 361005, China; School of Resource and Chemical Engineering, Sanming University, Sanming, 365004, China
| | - Guowen Dong
- School of Resource and Chemical Engineering, Sanming University, Sanming, 365004, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, 361005, China.
| | - Yuanpeng Wang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, 361005, China.
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19
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Laura M, Jo P. No acetogen is equal: Strongly different H 2 thresholds reflect diverse bioenergetics in acetogenic bacteria. Environ Microbiol 2023; 25:2032-2040. [PMID: 37209014 DOI: 10.1111/1462-2920.16429] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 05/09/2023] [Indexed: 05/21/2023]
Abstract
Acetogens share the capacity to convert H2 and CO2 into acetate for energy conservation (ATP synthesis). This reaction is attractive for applications, such as gas fermentation and microbial electrosynthesis. Different H2 partial pressures prevail in these distinctive applications (low concentrations during microbial electrosynthesis [<40 Pa] vs. high concentrations with gas fermentation [>9%]). Strain selection thus requires understanding of how different acetogens perform under different H2 partial pressures. Here, we determined the H2 threshold (H2 partial pressure at which acetogenesis halts) for eight different acetogenic strains under comparable conditions. We found a three orders of magnitude difference between the lowest and highest H2 threshold (6 ± 2 Pa for Sporomusa ovata vs. 1990 ± 67 Pa for Clostridium autoethanogenum), while Acetobacterium strains had intermediate H2 thresholds. We used these H2 thresholds to estimate ATP gains, which ranged from 0.16 to 1.01 mol ATP per mol acetate (S. ovata vs. C. autoethanogenum). The experimental H2 thresholds thus suggest strong differences in the bioenergetics of acetogenic strains and possibly also in their growth yields and kinetics. We conclude that no acetogen is equal and that a good understanding of their differences is essential to select the most optimal strain for different biotechnological applications.
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Affiliation(s)
- Munoz Laura
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
| | - Philips Jo
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
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20
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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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21
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Zhang H, Zhang C, Nie X, Wu Y, Yang C, Jiang W, Gu Y. Pleiotropic Regulator GssR Positively Regulates Autotrophic Growth of Gas-Fermenting Clostridium ljungdahlii. Microorganisms 2023; 11:1968. [PMID: 37630531 PMCID: PMC10458427 DOI: 10.3390/microorganisms11081968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/29/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023] Open
Abstract
Clostridium ljungdahlii is a representative autotrophic acetogen capable of producing multiple chemicals from one-carbon gases (CO2/CO). The metabolic and regulatory networks of this carbon-fixing bacterium are interesting, but still remain minimally explored. Here, based on bioinformatics analysis followed by functional screening, we identified a RpiR family transcription factor (TF) that can regulate the autotrophic growth and carbon fixation of C. ljungdahlii. After deletion of the corresponding gene, the resulting mutant strain exhibited significantly impaired growth in gas fermentation, thus reducing the production of acetic acid and ethanol. In contrast, the overexpression of this TF gene could promote cell growth, indicating a positive regulatory effect of this TF in C. ljungdahlii. Thus, we named the TF as GssR (growth and solvent synthesis regulator). Through the following comparative transcriptomic analysis and biochemical verification, we discovered three important genes (encoding pyruvate carboxylase, carbon hunger protein CstA, and a BlaI family transcription factor) that were directly regulated by GssR. Furthermore, an upstream regulator, BirA, that could directly bind to gssR was found; thus, these two regulators may form a cascade regulation and jointly affect the physiology and metabolism of C. ljungdahlii. These findings substantively expand our understanding on the metabolic regulation of carbon fixation in gas-fermenting Clostridium species.
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Affiliation(s)
- Huan Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Can Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqun Nie
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuwei Wu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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22
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Moon J, Waschinger LM, Müller V. Lactate formation from fructose or C1 compounds in the acetogen Acetobacterium woodii by metabolic engineering. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12637-7. [PMID: 37417977 PMCID: PMC10390620 DOI: 10.1007/s00253-023-12637-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 07/08/2023]
Abstract
Anaerobic, acetogenic bacteria are promising biocatalysts for a sustainable bioeconomy since they capture and convert carbon dioxide to acetic acid. Hydrogen is an intermediate in acetate formation from organic as well as C1 substrates. Here, we analyzed mutants of the model acetogen Acetobacterium woodii in which either one of the two hydrogenases or both together were genetically deleted. In resting cells of the double mutant, hydrogen formation from fructose was completely abolished and carbon was redirected largely to lactate. The lactate/fructose and lactate/acetate ratios were 1.24 and 2.76, respectively. We then tested for lactate formation from methyl groups (derived from glycine betaine) and carbon monoxide. Indeed, also under these conditions lactate and acetate were formed in equimolar amounts with a lactate/acetate ratio of 1.13. When the electron-bifurcating lactate dehydrogenase/ETF complex was genetically deleted, lactate formation was completely abolished. These experiments demonstrate the capability of A. woodii to produce lactate from fructose but also from promising C1 substrates, methyl groups and carbon monoxide. This adds an important milestone towards generation of a value chain leading from CO2 to value-added compounds. KEY POINTS: • Resting cells of the ΔhydBA/hdcr mutant of Acetobacterium woodii produced lactate from fructose or methyl groups + CO • Lactate formation from methyl groups + CO was completely abolished after deletion of lctBCD • Metabolic engineering of a homoacetogen to lactate formation gives a potential for industrial applications.
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Affiliation(s)
- Jimyung Moon
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, D-60438, Frankfurt, Germany
| | - Lara M Waschinger
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, D-60438, Frankfurt, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, D-60438, Frankfurt, Germany.
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23
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Elisiário MP, Van Hecke W, De Wever H, Noorman H, Straathof AJJ. Acetic acid, growth rate, and mass transfer govern shifts in CO metabolism of Clostridium autoethanogenum. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12670-6. [PMID: 37410136 PMCID: PMC10390632 DOI: 10.1007/s00253-023-12670-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/07/2023]
Abstract
Syngas fermentation is a leading microbial process for the conversion of carbon monoxide, carbon dioxide, and hydrogen to valuable biochemicals. Clostridium autoethanogenum stands as a model organism for this process, showcasing its ability to convert syngas into ethanol industrially with simultaneous fixation of carbon and reduction of greenhouse gas emissions. A deep understanding on the metabolism of this microorganism and the influence of operational conditions on fermentation performance is key to advance the technology and enhancement of production yields. In this work, we studied the individual impact of acetic acid concentration, growth rate, and mass transfer rate on metabolic shifts, product titres, and rates in CO fermentation by C. autoethanogenum. Through continuous fermentations performed at a low mass transfer rate, we measured the production of formate in addition to acetate and ethanol. We hypothesise that low mass transfer results in low CO concentrations, leading to reduced activity of the Wood-Ljungdahl pathway and a bottleneck in formate conversion, thereby resulting in the accumulation of formate. The supplementation of the medium with exogenous acetate revealed that undissociated acetic acid concentration increases and governs ethanol yield and production rates, assumedly to counteract the inhibition by undissociated acetic acid. Since acetic acid concentration is determined by growth rate (via dilution rate), mass transfer rate, and working pH, these variables jointly determine ethanol production rates. These findings have significant implications for process optimisation as targeting an optimal undissociated acetic acid concentration can shift metabolism towards ethanol production. KEY POINTS: • Very low CO mass transfer rate leads to leaking of intermediate metabolite formate. • Undissociated acetic acid concentration governs ethanol yield on CO and productivity. • Impact of growth rate, mass transfer rate, and pH were considered jointly.
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Affiliation(s)
- Marina P Elisiário
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629HZ, Delft, The Netherlands
- Flemish Institute for Technological Research (VITO), Boeretang 200, 2400, Mol, Belgium
| | - Wouter Van Hecke
- Flemish Institute for Technological Research (VITO), Boeretang 200, 2400, Mol, Belgium
| | - Heleen De Wever
- Flemish Institute for Technological Research (VITO), Boeretang 200, 2400, Mol, Belgium
| | - Henk Noorman
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629HZ, Delft, The Netherlands
- Royal DSM, Alexander Fleminglaan 1, 2613 AX, Delft, The Netherlands
| | - Adrie J J Straathof
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629HZ, Delft, The Netherlands.
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24
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Kim JY, Lee M, Oh S, Kang B, Yasin M, Chang IS. Acetogen and acetogenesis for biological syngas valorization. BIORESOURCE TECHNOLOGY 2023; 384:129368. [PMID: 37343794 DOI: 10.1016/j.biortech.2023.129368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 06/23/2023]
Abstract
The bioconversion of syngas using (homo)acetogens as biocatalysts shows promise as a viable option due to its higher selectivity and milder reaction conditions compared to thermochemical conversion. The current bioconversion process operates primarily to produce C2 chemicals (e.g., acetate and ethanol) with sufficient technology readiness levels (TRLs) in process engineering (as midstream) and product purification (as downstream). However, the economic feasibility of this process could be improved with greater biocatalytic options in the upstream phase. This review focuses on the Wood-Ljungdahl pathway (WLP) which is a biological syngas-utilization pathway, redox balance and ATP generation, suggesting that the use of a specific biocatalysts including Eubacterium limosum could be advantageous in syngas valorization. A pertinent strategy to mainly produce chemicals with a high degree of reduction is also provided with examples of flux control, mixed cultivation and mixotrophy. Finally, this article presents future direction of industrial utilization of syngas fermentation.
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Affiliation(s)
- Ji-Yeon Kim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Mungyu Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Soyoung Oh
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Byeongchan Kang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Muhammad Yasin
- Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Pakistan
| | - In Seop Chang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea; Research Center for Innovative Energy and Carbon Optimized Synthesis for Chemicals (inn-ECOSysChem), Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea.
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25
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Alleman AB, Peters JW. Mechanisms for Generating Low Potential Electrons across the Metabolic Diversity of Nitrogen-Fixing Bacteria. Appl Environ Microbiol 2023; 89:e0037823. [PMID: 37154716 PMCID: PMC10231201 DOI: 10.1128/aem.00378-23] [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] [Indexed: 05/10/2023] Open
Abstract
The availability of fixed nitrogen is a limiting factor in the net primary production of all ecosystems. Diazotrophs overcome this limit through the conversion of atmospheric dinitrogen to ammonia. Diazotrophs are phylogenetically diverse bacteria and archaea that exhibit a wide range of lifestyles and metabolisms, including obligate anaerobes and aerobes that generate energy through heterotrophic or autotrophic metabolisms. Despite the diversity of metabolisms, all diazotrophs use the same enzyme, nitrogenase, to reduce N2. Nitrogenase is an O2-sensitive enzyme that requires a high amount of energy in the form of ATP and low potential electrons carried by ferredoxin (Fd) or flavodoxin (Fld). This review summarizes how the diverse metabolisms of diazotrophs utilize different enzymes to generate low potential reducing equivalents for nitrogenase catalysis. These enzymes include substrate-level Fd oxidoreductases, hydrogenases, photosystem I or other light-driven reaction centers, electron bifurcating Fix complexes, proton motive force-driven Rnf complexes, and Fd:NAD(P)H oxidoreductases. Each of these enzymes is critical for generating low potential electrons while simultaneously integrating the native metabolism to balance nitrogenase's overall energy needs. Understanding the diversity of electron transport systems to nitrogenase in various diazotrophs will be essential to guide future engineering strategies aimed at expanding the contributions of biological nitrogen fixation in agriculture.
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Affiliation(s)
- Alexander B. Alleman
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - John W. Peters
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
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26
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Frolov EN, Elcheninov AG, Gololobova AV, Toshchakov SV, Novikov AA, Lebedinsky AV, Kublanov IV. Obligate autotrophy at the thermodynamic limit of life in a new acetogenic bacterium. Front Microbiol 2023; 14:1185739. [PMID: 37250036 PMCID: PMC10213532 DOI: 10.3389/fmicb.2023.1185739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 04/24/2023] [Indexed: 05/31/2023] Open
Abstract
One of the important current issues of bioenergetics is the establishment of the thermodynamic limits of life. There is still no final understanding of what is the minimum value of the energy yield of a reaction that is sufficient to be used by an organism (the so-called "biological quantum of energy"). A reasonable model for determination of the minimal energy yield would be microorganisms capable of living on low-energy substrates, such as acetogenic prokaryotes. The most prominent metabolic feature of acetogens is autotrophic growth with molecular hydrogen and carbon dioxide as the substrates, which is hardly competitive in environments. Most probably, that is why only facultative autotrophic acetogens have been known so far. Here, we describe the first obligately autotrophic acetogenic bacterium Aceticella autotrophica gen. nov., sp. nov., strain 3443-3AcT. Phylogenetically, the new genus falls into a monophyletic group of heterotrophic bacteria of the genera Thermoanaerobacterium, Thermoanaerobacter, and Caldanaerobacter (hereinafter referred to as TTC group), where the sole acetogenic representative has so far been the facultatively autotrophic Thermoanaerobacter kivui. A. autotrophica and T. kivui both are acetogens employing energy-converting hydrogenase (Ech-acetogens) that are likely to have inherited the acetogenesis capacity vertically from common ancestor. However, their acetogenic machineries have undergone different adjustments by gene replacements due to horizontal gene transfers from different donors. Obligate autotrophy of A. autotrophica is associated with the lack of many sugar transport systems and carbohydrate catabolism enzymes that are present in other TTC group representatives, including T. kivui.
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Affiliation(s)
- Evgenii N. Frolov
- Federal Research Center of Biotechnology, Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia
| | - Alexander G. Elcheninov
- Federal Research Center of Biotechnology, Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia
| | - Alexandra V. Gololobova
- Federal Research Center of Biotechnology, Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia
| | - Stepan V. Toshchakov
- Kurchatov Center for Genome Research, National Research Center “Kurchatov Institute”, Moscow, Russia
| | - Andrei A. Novikov
- Department of Physical and Colloid Chemistry, Gubkin University, Moscow, Russia
| | - Alexander V. Lebedinsky
- Federal Research Center of Biotechnology, Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia
| | - Ilya V. Kublanov
- Federal Research Center of Biotechnology, Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia
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27
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Takemura K, Kato J, Kato S, Fujii T, Wada K, Iwasaki Y, Aoi Y, Matsushika A, Morita T, Murakami K, Nakashimada Y. Enhancing acetone production from H 2 and CO 2 using supplemental electron acceptors in an engineered Moorella thermoacetica. J Biosci Bioeng 2023:S1389-1723(23)00112-3. [PMID: 37100649 DOI: 10.1016/j.jbiosc.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/08/2023] [Accepted: 04/02/2023] [Indexed: 04/28/2023]
Abstract
Acetogens grow autotrophically and use hydrogen (H2) as the energy source to fix carbon dioxide (CO2). This feature can be applied to gas fermentation, contributing to a circular economy. A challenge is the gain of cellular energy from H2 oxidation, which is substantially low, especially when acetate formation coupled with ATP production is diverted to other chemicals in engineered strains. Indeed, an engineered strain of the thermophilic acetogen Moorella thermoacetica that produces acetone lost autotrophic growth on H2 and CO2. We aimed to recover autotrophic growth and enhance acetone production, in which ATP production was assumed to be a limiting factor, by supplementing with electron acceptors. Among the four selected electron acceptors, thiosulfate and dimethyl sulfoxide (DMSO) enhanced both bacterial growth and acetone titers. DMSO was the most effective and was further analyzed. We showed that DMSO supplementation enhanced intracellular ATP levels, leading to increased acetone production. Although DMSO is an organic compound, it functions as an electron acceptor, not a carbon source. Thus, supplying electron acceptors is a potential strategy to complement the low ATP production caused by metabolic engineering and to improve chemical production from H2 and CO2.
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Affiliation(s)
- Kaisei Takemura
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Junya Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Setsu Kato
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Tatsuya Fujii
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Keisuke Wada
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Yuki Iwasaki
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Yoshiteru Aoi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan
| | - Akinori Matsushika
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan; National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Tomotake Morita
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Katsuji Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
| | - Yutaka Nakashimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8530, Japan.
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28
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Moon J, Schubert A, Waschinger LM, Müller V. Reprogramming the metabolism of an acetogenic bacterium to homoformatogenesis. THE ISME JOURNAL 2023:10.1038/s41396-023-01411-2. [PMID: 37061584 DOI: 10.1038/s41396-023-01411-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/30/2023] [Accepted: 04/04/2023] [Indexed: 04/17/2023]
Abstract
Methyl groups are abundant in anoxic environments and their utilization as carbon and energy sources by microorganisms involves oxidation of the methyl groups to CO2, followed by transfer of the electrons to an acceptor. In acetogenic bacteria, the electron acceptor is CO2 that is reduced to enzyme bound carbon monoxide, the precursor of the carboxyl group in acetate. Here, we describe the generation of a mutant of the acetogen Acetobacterium woodii in which the last step in methyl group oxidation, formate oxidation to CO2 catalyzed by the HDCR enzyme, has been genetically deleted. The mutant grew on glycine betaine as methyl group donor, and in contrast to the wild type, formed formate alongside acetate, in a 1:2 ratio, demonstrating that methyl group oxidation stopped at the level of formate and reduced electron carriers were reoxidized by CO2 reduction to acetate. In the presence of the alternative electron acceptor caffeate, CO2 was no longer reduced to acetate, formate was the only product and all the carbon went to formate. Apparently, acetogenesis was not required to sustain formatogenic growth. This is the first demonstration of a genetic reprogramming of an acetogen into a formatogen that grows by homoformatogenesis from methyl groups. Formate production from methyl groups is not only of biotechnological interest but also for the mechanism of electron transfer in syntrophic interactions in anoxic environments.
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Affiliation(s)
- Jimyung Moon
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue Str. 9, D-60438, Frankfurt, Germany
| | - Anja Schubert
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue Str. 9, D-60438, Frankfurt, Germany
| | - Lara M Waschinger
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue Str. 9, D-60438, Frankfurt, Germany
| | - Volker Müller
- Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Max-von-Laue Str. 9, D-60438, Frankfurt, Germany.
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29
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Fernández-Blanco C, Robles-Iglesias R, Naveira-Pazos C, Veiga MC, Kennes C. Production of biofuels from C 1 -gases with Clostridium and related bacteria-Recent advances. Microb Biotechnol 2023; 16:726-741. [PMID: 36661185 PMCID: PMC10034633 DOI: 10.1111/1751-7915.14220] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 01/02/2023] [Accepted: 01/07/2023] [Indexed: 01/21/2023] Open
Abstract
Clostridium spp. are suitable for the bioconversion of C1 -gases (e.g., CO2 , CO and syngas) into different bioproducts. These products can be used as biofuels and are reviewed here, focusing on ethanol, butanol and hexanol, mainly. The production of higher alcohols (e.g., butanol and hexanol) has hardly been reviewed. Parameters affecting the optimization of the bioconversion process and bioreactor performance are addressed as well as the pathways involved in these bioconversions. New aspects, such as mixotrophy and sugar versus gas fermentation, are also reviewed. In addition, Clostridia can also produce higher alcohols from the integration of the Wood-Ljungdahl pathway and the reverse ß-oxidation pathway, which has also not yet been comprehensively reviewed. In the latter process, the acetogen uses the reducing power of CO/syngas to reduce C4 or C6 fatty acids, previously produced by a chain elongating microorganism (commonly Clostridium kluyveri), into the corresponding bioalcohol.
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Affiliation(s)
- Carla Fernández-Blanco
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research-Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña, La Coruña, Spain
| | - Raúl Robles-Iglesias
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research-Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña, La Coruña, Spain
| | - Cecilia Naveira-Pazos
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research-Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña, La Coruña, Spain
| | - María C Veiga
- Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research-Centro de Investigaciones Científicas Avanzadas (CICA), BIOENGIN Group, University of La Coruña, 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, La Coruña, Spain
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30
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Al-Mamun A, Ahmed W, Jafary T, Nayak JK, Al-Nuaimi A, Sana A. Recent advances in microbial electrosynthesis system: Metabolic investigation and process optimization. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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31
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Xu J, Wang J, Ma C, Wei Z, Zhai Y, Tian N, Zhu Z, Xue M, Li D. Embracing a low-carbon future by the production and marketing of C1 gas protein. Biotechnol Adv 2023; 63:108096. [PMID: 36621726 DOI: 10.1016/j.biotechadv.2023.108096] [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: 08/29/2022] [Revised: 12/14/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
Food scarcity and environmental deterioration are two major problems that human populations currently face. Fortunately, the disruptive innovation of raw food materials has been stimulated by the rapid evolution of biomanufacturing. Therefore, it is expected that the new trends in technology will not only alter the natural resource-dependent food production systems and the traditional way of life but also reduce and assimilate the greenhouse gases released into the atmosphere. This review article summarizes the metabolic pathways associated with C1 gas conversion and the production of single-cell protein for animal feed. Moreover, the protein function, worldwide authorization, market access, and methods to overcome challenges in C1 gas assimilation microbial cell factory construction are also provided. With widespread attention and increasing policy support, the production of C1 gas protein will bring more opportunities and make tremendous contributions to our sustainable future.
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Affiliation(s)
- Jian Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Jie Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chunling Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; Haihe Laboratory of Synthetic Biology, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China
| | - Zuoxi Wei
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Yida Zhai
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Na Tian
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Zhiguang Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China.
| | - Min Xue
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Demao Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China.
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32
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Moreira JPC, Heap JT, Alves JI, Domingues L. Developing a genetic engineering method for Acetobacterium wieringae to expand one-carbon valorization pathways. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:24. [PMID: 36788587 PMCID: PMC9930230 DOI: 10.1186/s13068-023-02259-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 01/05/2023] [Indexed: 02/16/2023]
Abstract
BACKGROUND Developing new bioprocesses to produce chemicals and fuels with reduced production costs will greatly facilitate the replacement of fossil-based raw materials. In most fermentation bioprocesses, the feedstock usually represents the highest cost, which becomes the target for cost reduction. Additionally, the biorefinery concept advocates revenue growth from the production of several compounds using the same feedstock. Taken together, the production of bio commodities from low-cost gas streams containing CO, CO2, and H2, obtained from the gasification of any carbon-containing waste streams or off-gases from heavy industry (steel mills, processing plants, or refineries), embodies an opportunity for affordable and renewable chemical production. To achieve this, by studying non-model autotrophic acetogens, current limitations concerning low growth rates, toxicity by gas streams, and low productivity may be overcome. The Acetobacterium wieringae strain JM is a novel autotrophic acetogen that is capable of producing acetate and ethanol. It exhibits faster growth rates on various gaseous compounds, including carbon monoxide, compared to other Acetobacterium species, making it potentially useful for industrial applications. The species A. wieringae has not been genetically modified, therefore developing a genetic engineering method is important for expanding its product portfolio from gas fermentation and overall improving the characteristics of this acetogen for industrial demands. RESULTS This work reports the development and optimization of an electrotransformation protocol for A. wieringae strain JM, which can also be used in A. wieringae DSM 1911, and A. woodii DSM 1030. We also show the functionality of the thiamphenicol resistance marker, catP, and the functionality of the origins of replication pBP1, pCB102, pCD6, and pIM13 in all tested Acetobacterium strains, with transformation efficiencies of up to 2.0 × 103 CFU/μgDNA. Key factors affecting electrotransformation efficiency include OD600 of cell harvesting, pH of resuspension buffer, the field strength of the electric pulse, and plasmid amount. Using this method, the acetone production operon from Clostridium acetobutylicum was efficiently introduced in all tested Acetobacterium spp., leading to non-native biochemical acetone production via plasmid-based expression. CONCLUSIONS A. wieringae can be electrotransformed at high efficiency using different plasmids with different replication origins. The electrotransformation procedure and tools reported here unlock the genetic and metabolic manipulation of the biotechnologically relevant A. wieringae strains. For the first time, non-native acetone production is shown in A. wieringae.
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Affiliation(s)
- João P. C. Moreira
- grid.10328.380000 0001 2159 175XCEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal ,LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - John T. Heap
- grid.4563.40000 0004 1936 8868School of Life Sciences, University of Nottingham, Biodiscovery Institute, University Park, Nottingham, NG7 2RD UK
| | - Joana I. Alves
- grid.10328.380000 0001 2159 175XCEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal ,LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal. .,LABBELS - Associate Laboratory, Braga/Guimarães, Portugal.
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Romans-Casas M, Perona-Vico E, Dessì P, Bañeras L, Balaguer MD, Puig S. Boosting ethanol production rates from carbon dioxide in MES cells under optimal solventogenic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159124. [PMID: 36179842 DOI: 10.1016/j.scitotenv.2022.159124] [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: 07/18/2022] [Revised: 09/01/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Microbial Electrosynthesis (MES) has been widely applied for acetic acid (HA) production from CO2 and electricity. Ethanol (EtOH) has a higher market value than HA, and wide application in industry and as a biofuel. However, it has only been obtained sporadically and at low concentrations, probably due to sub-optimal operating conditions. This study aimed at enhancing EtOH productivity in MES cells by jointly optimising key operation parameters, including pH, H2 and CO2 partial pressure (pH2 and pCO2), and HA concentration, to promote solventogenesis. Two H-type cells were operated in fed-batch mode at -0.8 V vs. SHE with CO2 as the sole carbon source. A mixed culture, enriched with Clostridium ljungdahlii was used as the biocatalyst. The combination of low pH (<4.5) and pCO2 (<0.3 atm), along with high HA concentration (about 6 g L-1) and pH2 (>3 atm), were mandatory conditions for maintaining an efficient solventogenic culture, dominated by Clostridium sp., capable of high-rate EtOH production. The maximum EtOH production rate was 10.95 g m-2 d-1, and a concentration of 5.28 g L-1 was achieved. Up to 30 % of the electrons and 15.2 % of the carbon provided were directed towards EtOH production, and 28.1 kWh were required for the synthesis of 1 kg of EtOH from CO2. These results highlight that strict conditions are required for a continuous, reliable, EtOH production in MES cells. Future investigation should focus on improving cell configuration to achieve EtOH production at higher current densities while minimizing the electric energy input.
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Affiliation(s)
- M Romans-Casas
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain
| | - E Perona-Vico
- gEMM. Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 40, E-17003 Girona, Spain
| | - P Dessì
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain
| | - L Bañeras
- gEMM. Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 40, E-17003 Girona, Spain
| | - M D Balaguer
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain
| | - S Puig
- LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003 Girona, Spain.
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Serrano-Gutiérrez M, Merino E. Antisense-acting riboswitches: A poorly characterized yet important model of transcriptional regulation in prokaryotic organisms. PLoS One 2023; 18:e0281744. [PMID: 36809273 PMCID: PMC9943018 DOI: 10.1371/journal.pone.0281744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/30/2023] [Indexed: 02/23/2023] Open
Abstract
Riboswitches are RNA elements involved in regulating genes that participate in the biosynthesis or transport of essential metabolites. They are characterized by their ability to recognize their target molecules with high affinity and specificity. Riboswitches are commonly cotranscribed with their target genes and are located at the 5' end of their transcriptional units. To date, only two exceptional cases of riboswitches being situated at the 3' end and transcribing in the antisense direction of their regulated genes have been described. The first case involves a SAM riboswitch located at the 3' end of the ubiG-mccB-mccA operon in Clostridium acetobutylicum involved in converting methionine to cysteine. The second case concerns a Cobalamin riboswitch in Listeria monocytogenes that regulates the transcription factor PocR related to this organism's pathogenic process. In almost a decade since the first descriptions of antisense-acting riboswitches, no new examples have been described. In this work, we performed a computational analysis to identify new examples of antisense-acting riboswitches. We found 292 cases in which, according to the available information, we infer that the expected regulation of the riboswitch is consistent with the signaling molecule it senses and the metabolic function of the regulated gene. The metabolic implications of this novel type of regulation are thoroughly discussed.
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Affiliation(s)
- Mariela Serrano-Gutiérrez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Enrique Merino
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail:
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Dykstra JC, van Oort J, Yazdi AT, Vossen E, Patinios C, van der Oost J, Sousa DZ, Kengen SWM. Metabolic engineering of Clostridium autoethanogenum for ethyl acetate production from CO. Microb Cell Fact 2022; 21:243. [DOI: 10.1186/s12934-022-01964-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 10/18/2022] [Indexed: 11/25/2022] Open
Abstract
Abstract
Background
Ethyl acetate is a bulk chemical traditionally produced via energy intensive chemical esterification. Microbial production of this compound offers promise as a more sustainable alternative process. So far, efforts have focused on using sugar-based feedstocks for microbial ester production, but extension to one-carbon substrates, such as CO and CO2/H2, is desirable. Acetogens present a promising microbial platform for the production of ethyl esters from these one-carbon substrates.
Results
We engineered the acetogen C. autoethanogenum to produce ethyl acetate from CO by heterologous expression of an alcohol acetyltransferase (AAT), which catalyzes the formation of ethyl acetate from acetyl-CoA and ethanol. Two AATs, Eat1 from Kluyveromyces marxianus and Atf1 from Saccharomyces cerevisiae, were expressed in C. autoethanogenum. Strains expressing Atf1 produced up to 0.2 mM ethyl acetate. Ethyl acetate production was barely detectable (< 0.01 mM) for strains expressing Eat1. Supplementation of ethanol was investigated as potential boost for ethyl acetate production but resulted only in a 1.5-fold increase (0.3 mM ethyl acetate). Besides ethyl acetate, C. autoethanogenum expressing Atf1 could produce 4.5 mM of butyl acetate when 20 mM butanol was supplemented to the growth medium.
Conclusions
This work offers for the first time a proof-of-principle that autotrophic short chain ester production from C1-carbon feedstocks is possible and offers leads on how this approach can be optimized in the future.
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Perret L, Lacerda de Oliveira Campos B, Herrera Delgado K, Zevaco TA, Neumann A, Sauer J. CO
x
Fixation to Elementary Building Blocks: Anaerobic Syngas Fermentation vs. Chemical Catalysis. CHEM-ING-TECH 2022. [DOI: 10.1002/cite.202200153] [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)
- Lukas Perret
- Karlsruhe Institute of Technology Institute of Catalysis Research and Technology 76344 Eggenstein-Leopoldshafen Germany
| | | | - Karla Herrera Delgado
- Karlsruhe Institute of Technology Institute of Catalysis Research and Technology 76344 Eggenstein-Leopoldshafen Germany
| | - Thomas A. Zevaco
- Karlsruhe Institute of Technology Institute of Catalysis Research and Technology 76344 Eggenstein-Leopoldshafen Germany
| | - Anke Neumann
- Karlsruhe Institute of Technology Institute of Process Engineering in Life Sciences 2 – Technical Biology 76131 Karlsruhe Germany
| | - Jörg Sauer
- Karlsruhe Institute of Technology Institute of Catalysis Research and Technology 76344 Eggenstein-Leopoldshafen Germany
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Luo D, Zhang K, Song T, Xie J. Improving cell permeability and stimulating biofilm to release extracellular polymeric substances with lysozyme for enhanced acetate production in microbial electrosynthesis. J CO2 UTIL 2022. [DOI: 10.1016/j.jcou.2022.102204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Genome-Scale Mining of Acetogens of the Genus Clostridium Unveils Distinctive Traits in [FeFe]- and [NiFe]-Hydrogenase Content and Maturation. Microbiol Spectr 2022; 10:e0101922. [PMID: 35735976 PMCID: PMC9431212 DOI: 10.1128/spectrum.01019-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Knowledge of the organizational and functional properties of hydrogen metabolism is pivotal to the construction of a framework supportive of a hydrogen-fueled low-carbon economy. Hydrogen metabolism relies on the mechanism of action of hydrogenases. In this study, we investigated the genomes of several industrially relevant acetogens of the genus Clostridium (C. autoethanogenum, C. ljungdahlii, C. carboxidivorans, C. drakei, C. scatologenes, C. coskatii, C. ragsdalei, C. sp. AWRP) to systematically identify their intriguingly diversified hydrogenases’ repertoire. An entirely computational annotation pipeline unveiled common and strain-specific traits in the functional content of [NiFe]- and [FeFe]-hydrogenases. Hydrogenases were identified and categorized into functionally distinct classes by the combination of sequence homology, with respect to a database of curated nonredundant hydrogenases, with the analysis of sequence patterns characteristic of the mode of action of [FeFe]- and [NiFe]-hydrogenases. The inspection of the genes in the neighborhood of the catalytic subunits unveiled a wide agreement between their genomic arrangement and the gene organization templates previously developed for the predicted hydrogenase classes. Subunits’ characterization of the identified hydrogenases allowed us to glean some insights on the redox cofactor-binding determinants in the diaphorase subunits of the electron-bifurcating [FeFe]-hydrogenases. Finally, the reliability of the inferred hydrogenases was corroborated by the punctual analysis of the maturation proteins necessary for the biosynthesis of [NiFe]- and [FeFe]-hydrogenases. IMPORTANCE Mastering hydrogen metabolism can support a sustainable carbon-neutral economy. Of the many microorganisms metabolizing hydrogen, acetogens of the genus Clostridium are appealing, with some of them already in usage as industrial workhorses. Having provided detailed information on the hydrogenase content of an unprecedented number of clostridial acetogens at the gene level, our study represents a valuable knowledge base to deepen our understanding of hydrogenases’ functional specificity and/or redundancy and to develop a large array of biotechnological processes. We also believe our study could serve as a basis for future strain-engineering approaches, acting at the hydrogenases’ level or at the level of their maturation proteins. On the other side, the wealth of functional elements discussed in relation to the identified hydrogenases is worthy of further investigation by biochemical and structural studies to ultimately lead to the usage of these enzymes as valuable catalysts.
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Stark C, Münßinger S, Rosenau F, Eikmanns BJ, Schwentner A. The Potential of Sequential Fermentations in Converting C1 Substrates to Higher-Value Products. Front Microbiol 2022; 13:907577. [PMID: 35722332 PMCID: PMC9204031 DOI: 10.3389/fmicb.2022.907577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Today production of (bulk) chemicals and fuels almost exclusively relies on petroleum-based sources, which are connected to greenhouse gas release, fueling climate change. This increases the urgence to develop alternative bio-based technologies and processes. Gaseous and liquid C1 compounds are available at low cost and often occur as waste streams. Acetogenic bacteria can directly use C1 compounds like CO, CO2, formate or methanol anaerobically, converting them into acetate and ethanol for higher-value biotechnological products. However, these microorganisms possess strict energetic limitations, which in turn pose limitations to their potential for biotechnological applications. Moreover, efficient genetic tools for strain improvement are often missing. However, focusing on the metabolic abilities acetogens provide, they can prodigiously ease these technological disadvantages. Producing acetate and ethanol from C1 compounds can fuel via bio-based intermediates conversion into more energy-demanding, higher-value products, by deploying aerobic organisms that are able to grow with acetate/ethanol as carbon and energy source. Promising new approaches have become available combining these two fermentation steps in sequential approaches, either as separate fermentations or as integrated two-stage fermentation processes. This review aims at introducing, comparing, and evaluating the published approaches of sequential C1 fermentations, delivering a list of promising organisms for the individual fermentation steps and giving an overview of the existing broad spectrum of products based on acetate and ethanol. Understanding of these pioneering approaches allows collecting ideas for new products and may open avenues toward making full use of the technological potential of these concepts for establishment of a sustainable biotechnology.
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Affiliation(s)
- Christina Stark
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Sini Münßinger
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Frank Rosenau
- Institute of Pharmaceutical Biotechnology, University of Ulm, Ulm, Germany
| | - Bernhard J. Eikmanns
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
- *Correspondence: Bernhard J. Eikmanns,
| | - Andreas Schwentner
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
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Lauer I, Philipps G, Jennewein S. Metabolic engineering of Clostridium ljungdahlii for the production of hexanol and butanol from CO 2 and H 2. Microb Cell Fact 2022; 21:85. [PMID: 35568911 PMCID: PMC9107641 DOI: 10.1186/s12934-022-01802-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The replacement of fossil fuels and petrochemicals with sustainable alternatives is necessary to mitigate the effects of climate change and also to counteract diminishing fossil resources. Acetogenic microorganisms such as Clostridium spp. are promising sources of fuels and basic chemical precursors because they efficiently utilize CO and CO2 as carbon source. However the conversion into high titers of butanol and hexanol is challenging. RESULTS Using a metabolic engineering approach we transferred a 17.9-kb gene cluster via conjugation, containing 13 genes from C. kluyveri and C. acetobutylicum for butanol and hexanol biosynthesis, into C. ljungdahlii. Plasmid-based expression resulted in 1075 mg L-1 butanol and 133 mg L-1 hexanol from fructose in complex medium, and 174 mg L-1 butanol and 15 mg L-1 hexanol from gaseous substrate (20% CO2 and 80% H2) in minimal medium. Product formation was increased by the genomic integration of the heterologous gene cluster. We confirmed the expression of all 13 enzymes by targeted proteomics and identified potential rate-limiting steps. Then, we removed the first-round selection marker using CRISPR/Cas9 and integrated an additional 7.8 kb gene cluster comprising 6 genes from C. carboxidivorans. This led to a significant increase in the hexanol titer (251 mg L-1) at the expense of butanol (158 mg L-1), when grown on CO2 and H2 in serum bottles. Fermentation of this strain at 2-L scale produced 109 mg L-1 butanol and 393 mg L-1 hexanol. CONCLUSIONS We thus confirmed the function of the butanol/hexanol biosynthesis genes and achieved hexanol biosynthesis in the syngas-fermenting species C. ljungdahlii for the first time, reaching the levels produced naturally by C. carboxidivorans. The genomic integration strain produced hexanol without selection and is therefore suitable for continuous fermentation processes.
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Affiliation(s)
- Ira Lauer
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, 52074, Aachen, Germany
| | - Gabriele Philipps
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, 52074, Aachen, Germany
| | - Stefan Jennewein
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, 52074, Aachen, Germany.
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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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Klask CM, Jäger B, Casini I, Angenent LT, Molitor B. Genetic Evidence Reveals the Indispensable Role of the rseC Gene for Autotrophy and the Importance of a Functional Electron Balance for Nitrate Reduction in Clostridium ljungdahlii. Front Microbiol 2022; 13:887578. [PMID: 35615511 PMCID: PMC9124969 DOI: 10.3389/fmicb.2022.887578] [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: 03/01/2022] [Accepted: 03/31/2022] [Indexed: 11/20/2022] Open
Abstract
For Clostridium ljungdahlii, the RNF complex plays a key role for energy conversion from gaseous substrates such as hydrogen and carbon dioxide. In a previous study, a disruption of RNF-complex genes led to the loss of autotrophy, while heterotrophy was still possible via glycolysis. Furthermore, it was shown that the energy limitation during autotrophy could be lifted by nitrate supplementation, which resulted in an elevated cellular growth and ATP yield. Here, we used CRISPR-Cas12a to delete: (1) the RNF complex-encoding gene cluster rnfCDGEAB; (2) the putative RNF regulator gene rseC; and (3) a gene cluster that encodes for a putative nitrate reductase. The deletion of either rnfCDGEAB or rseC resulted in a complete loss of autotrophy, which could be restored by plasmid-based complementation of the deleted genes. We observed a transcriptional repression of the RNF-gene cluster in the rseC-deletion strain during autotrophy and investigated the distribution of the rseC gene among acetogenic bacteria. To examine nitrate reduction and its connection to the RNF complex, we compared autotrophic and heterotrophic growth of our three deletion strains with either ammonium or nitrate. The rnfCDGEAB- and rseC-deletion strains failed to reduce nitrate as a metabolic activity in non-growing cultures during autotrophy but not during heterotrophy. In contrast, the nitrate reductase deletion strain was able to grow in all tested conditions but lost the ability to reduce nitrate. Our findings highlight the important role of the rseC gene for autotrophy, and in addition, contribute to understand the connection of nitrate reduction to energy metabolism.
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Affiliation(s)
- Christian-Marco Klask
- Environmental Biotechnology Group, Geo- and Environmental Science Center, University of Tübingen, Tübingen, Germany
| | - Benedikt Jäger
- Environmental Biotechnology Group, Geo- and Environmental Science Center, University of Tübingen, Tübingen, Germany
| | - Isabella Casini
- Environmental Biotechnology Group, Geo- and Environmental Science Center, University of Tübingen, Tübingen, Germany
| | - Largus T. Angenent
- Environmental Biotechnology Group, Geo- and Environmental Science Center, University of Tübingen, Tübingen, Germany
- Cluster of Excellence – Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Bastian Molitor
- Environmental Biotechnology Group, Geo- and Environmental Science Center, University of Tübingen, Tübingen, Germany
- Cluster of Excellence – Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- *Correspondence: Bastian Molitor,
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Joshi S, Mishra S. Recent advances in biofuel production through metabolic engineering. BIORESOURCE TECHNOLOGY 2022; 352:127037. [PMID: 35318143 DOI: 10.1016/j.biortech.2022.127037] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Rising global energy demands and climate crisis has created an unprecedented need for the bio-based circular economy to ensure sustainable development with the minimized carbon footprint. Along with conventional biofuels such as ethanol, microbes can be used to produce advanced biofuels which are equivalent to traditional fuels in their energy efficiencies and are compatible with already established infrastructure and hence can be directly blended in higher proportions without overhauling of the pre-existing setup. Metabolic engineering is at the frontiers to develop microbial chassis for biofuel bio-foundries to meet the industrial needs for clean energy. This review does a thorough inquiry of recent developments in metabolic engineering for increasing titers, rates, and yields (TRY) of biofuel production by engineered microorganisms.
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Affiliation(s)
- Swati Joshi
- ICMR-National Institute of Occupational Health (NIOH), Ahmedabad, Gujarat, India; Central University of Gujarat, Gandhinagar, Gujarat, India.
| | - SukhDev Mishra
- ICMR-National Institute of Occupational Health (NIOH), Ahmedabad, Gujarat, India
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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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Marcel M, Darina E, Patrick K, Aline H, Gabriele P, Stefan J, Jochen B. Impact of different trace elements on metabolic routes during heterotrophic growth of C. ljungdahlii investigated through online measurement of the carbon dioxide transfer rate. Biotechnol Prog 2022; 38:e3263. [PMID: 35434968 DOI: 10.1002/btpr.3263] [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: 01/27/2022] [Revised: 03/30/2022] [Accepted: 04/15/2022] [Indexed: 11/09/2022]
Abstract
Synthesis gas fermentation using acetogenic clostridia is a rapidly increasing research area. It offers the possibility to produce platform chemicals from sustainable C1 carbon sources. The Wood-Ljungdahl pathway (WLP), which allows acetogens to grow autotrophically, is also active during heterotrophic growth. It acts as an electron sink and allows for the utilization of a wide variety of soluble substrates and increases ATP yields during heterotrophic growth. While glycolysis leads to CO2 evolution, WLP activity results in CO2 fixation. Thus, a reduction of net CO2 emissions during growth with sugars is an indicator of WLP activity. To study the effect of trace elements and ventilation rates on the interaction between glycolysis and the WLP, the model acetogen Clostridium ljungdahlii was cultivated in YTF medium, a complex medium generally employed for heterotrophic growth, with fructose as growth substrate. The recently reported anaRAMOS device was used for online measurement of metabolic activity, in form of CO2 evolution. The addition of multiple trace elements (iron, cobalt, manganese, zinc, nickel, copper, selenium, and tungsten) was tested, to study the interaction between glycolysis and the Wood ljungdahl pathway. While the addition of iron(II) increased growth rates and ethanol production, added nickel(II) increased WLP activity and acetate formation, reducing net CO2 production by 28%. Also, higher CO2 availability through reduced volumetric gas flow resulted in 25% reduction of CO2 evolution. These online metabolic data demonstrate that the anaRAMOS is a valuable tool in the investigation of metabolic responses i.e. to determine nutrient requirements that results in reduced CO2 production. Thereby the media composition can be optimized depending on the specific goal. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mann Marcel
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
| | - Effert Darina
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
| | - Kottenhahn Patrick
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany.,Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, Aachen, Germany
| | - Hüser Aline
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
| | - Philipps Gabriele
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, Aachen, Germany
| | - Jennewein Stefan
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, Aachen, Germany
| | - Büchs Jochen
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
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Zhang C, Ottenheim C, Weingarten M, Ji L. Microbial Utilization of Next-Generation Feedstocks for the Biomanufacturing of Value-Added Chemicals and Food Ingredients. Front Bioeng Biotechnol 2022; 10:874612. [PMID: 35480982 PMCID: PMC9035589 DOI: 10.3389/fbioe.2022.874612] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/14/2022] [Indexed: 12/04/2022] Open
Abstract
Global shift to sustainability has driven the exploration of alternative feedstocks beyond sugars for biomanufacturing. Recently, C1 (CO2, CO, methane, formate and methanol) and C2 (acetate and ethanol) substrates are drawing great attention due to their natural abundance and low production cost. The advances in metabolic engineering, synthetic biology and industrial process design have greatly enhanced the efficiency that microbes use these next-generation feedstocks. The metabolic pathways to use C1 and C2 feedstocks have been introduced or enhanced into industrial workhorses, such as Escherichia coli and yeasts, by genetic rewiring and laboratory evolution strategies. Furthermore, microbes are engineered to convert these low-cost feedstocks to various high-value products, ranging from food ingredients to chemicals. This review highlights the recent development in metabolic engineering, the challenges in strain engineering and bioprocess design, and the perspectives of microbial utilization of C1 and C2 feedstocks for the biomanufacturing of value-added products.
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Affiliation(s)
- Congqiang Zhang
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- *Correspondence: Congqiang Zhang, ,
| | - Christoph Ottenheim
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Melanie Weingarten
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - LiangHui Ji
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
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Reji L, Cardarelli EL, Boye K, Bargar JR, Francis CA. Diverse ecophysiological adaptations of subsurface Thaumarchaeota in floodplain sediments revealed through genome-resolved metagenomics. THE ISME JOURNAL 2022; 16:1140-1152. [PMID: 34873295 PMCID: PMC8940955 DOI: 10.1038/s41396-021-01167-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 11/17/2021] [Accepted: 11/26/2021] [Indexed: 02/03/2023]
Abstract
The terrestrial subsurface microbiome contains vastly underexplored phylogenetic diversity and metabolic novelty, with critical implications for global biogeochemical cycling. Among the key microbial inhabitants of subsurface soils and sediments are Thaumarchaeota, an archaeal phylum that encompasses ammonia-oxidizing archaea (AOA) as well as non-ammonia-oxidizing basal lineages. Thaumarchaeal ecology in terrestrial systems has been extensively characterized, particularly in the case of AOA. However, there is little knowledge on the diversity and ecophysiology of Thaumarchaeota in deeper soils, as most lineages, particularly basal groups, remain uncultivated and underexplored. Here we use genome-resolved metagenomics to examine the phylogenetic and metabolic diversity of Thaumarchaeota along a 234 cm depth profile of hydrologically variable riparian floodplain sediments in the Wind River Basin near Riverton, Wyoming. Phylogenomic analysis of the metagenome-assembled genomes (MAGs) indicates a shift in AOA population structure from the dominance of the terrestrial Nitrososphaerales lineage in the well-drained top ~100 cm of the profile to the typically marine Nitrosopumilales in deeper, moister, more energy-limited sediment layers. We also describe two deeply rooting non-AOA MAGs with numerous unexpected metabolic features, including the reductive acetyl-CoA (Wood-Ljungdahl) pathway, tetrathionate respiration, a form III RuBisCO, and the potential for extracellular electron transfer. These MAGs also harbor tungsten-containing aldehyde:ferredoxin oxidoreductase, group 4f [NiFe]-hydrogenases and a canonical heme catalase, typically not found in Thaumarchaeota. Our results suggest that hydrological variables, particularly proximity to the water table, impart a strong control on the ecophysiology of Thaumarchaeota in alluvial sediments.
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Affiliation(s)
- Linta Reji
- grid.168010.e0000000419368956Department of Earth System Science, Stanford University, Stanford, CA USA ,grid.16750.350000 0001 2097 5006Present Address: Department of Geosciences, Princeton University, Princeton, NJ USA
| | - Emily L. Cardarelli
- grid.168010.e0000000419368956Department of Earth System Science, Stanford University, Stanford, CA USA ,grid.20861.3d0000000107068890Present Address: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA
| | - Kristin Boye
- grid.445003.60000 0001 0725 7771Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA USA
| | - John R. Bargar
- grid.445003.60000 0001 0725 7771Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA USA
| | - Christopher A. Francis
- grid.168010.e0000000419368956Department of Earth System Science, Stanford University, Stanford, CA USA
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Abstract
The majority of the genes present in bacterial genomes remain poorly characterized, with up to one-third of those that are protein encoding having no definitive function. Transposon insertion sequencing represents a high-throughput technique that can help rectify this deficiency. The technology, however, can only be realistically applied to those species in which high rates of DNA transfer can be achieved. Here, we have developed a number of approaches that overcome this barrier in the autotrophic species Clostridium autoethanogenum by using a mariner-based transposon system. The inherent instability of such systems in the Escherichia coli conjugation donor due to transposition events was counteracted through the incorporation of a conditionally lethal codA marker on the plasmid backbone. Relatively low frequencies of transformation of the plasmid into C. autoethanogenum were circumvented through the use of a plasmid that is conditional for replication coupled with the routine implementation of an Illumina library preparation protocol that eliminates plasmid-based reads. A transposon library was then used to determine the essential genes needed for growth using carbon monoxide as the sole carbon and energy source. IMPORTANCE Although microbial genome sequences are relatively easily determined, assigning gene function remains a bottleneck. Consequently, relatively few genes are well characterized, leaving the function of many as either hypothetical or entirely unknown. High-throughput transposon sequencing can help remedy this deficiency, but is generally only applicable to microbes with efficient DNA transfer procedures. These exclude many microorganisms of importance to humankind either as agents of disease or as industrial process organisms. Here, we developed approaches to facilitate transposon insertion sequencing in the acetogen Clostridium autoethanogenum, a chassis being exploited to convert single-carbon waste gases CO and CO2 into chemicals and fuels at an industrial scale. This allowed the determination of gene essentiality under heterotrophic and autotrophic growth, providing insights into the utilization of CO as a sole carbon and energy source. The strategies implemented are translatable and will allow others to apply transposon insertion sequencing to other microbes where DNA transfer has until now represented a barrier to progress.
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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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