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Wagner N, Wen L, Frazão CJR, Walther T. Next-generation feedstocks methanol and ethylene glycol and their potential in industrial biotechnology. Biotechnol Adv 2023; 69:108276. [PMID: 37918546 DOI: 10.1016/j.biotechadv.2023.108276] [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: 09/04/2023] [Revised: 10/13/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023]
Abstract
Microbial fermentation processes are expected to play an important role in reducing dependence on fossil-based raw materials for the production of everyday chemicals. In order to meet the growing demand for biotechnological products in the future, alternative carbon sources that do not compete with human nutrition must be exploited. The chemical conversion of the industrially emitted greenhouse gas CO2 into microbially utilizable platform chemicals such as methanol represents a sustainable strategy for the utilization of an abundant carbon source and has attracted enormous scientific interest in recent years. A relatively new approach is the microbial synthesis of products from the C2-compound ethylene glycol, which can also be synthesized from CO2 and non-edible biomass and, in addition, can be recovered from plastic waste. Here we summarize the main chemical routes for the synthesis of methanol and ethylene glycol from sustainable resources and give an overview of recent metabolic engineering work for establishing natural and synthetic microbial assimilation pathways. The different metabolic routes for C1 and C2 alcohol-dependent bioconversions were compared in terms of their theoretical maximum yields and their oxygen requirements for a wide range of value-added products. Assessment of the process engineering challenges for methanol and ethylene glycol-based fermentations underscores the theoretical advantages of new synthetic metabolic routes and advocates greater consideration of ethylene glycol, a C2 substrate that has received comparatively little attention to date.
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Affiliation(s)
- Nils Wagner
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany
| | - Linxuan Wen
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany
| | - Cláudio J R Frazão
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany
| | - Thomas Walther
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany.
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2
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Mitic BM, Troyer C, Lutz L, Baumschabl M, Hann S, Mattanovich D. The oxygen-tolerant reductive glycine pathway assimilates methanol, formate and CO 2 in the yeast Komagataella phaffii. Nat Commun 2023; 14:7754. [PMID: 38012236 PMCID: PMC10682033 DOI: 10.1038/s41467-023-43610-7] [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: 08/09/2023] [Accepted: 11/14/2023] [Indexed: 11/29/2023] Open
Abstract
The current climatic change is predominantly driven by excessive anthropogenic CO2 emissions. As industrial bioprocesses primarily depend on food-competing organic feedstocks or fossil raw materials, CO2 co-assimilation or the use of CO2-derived methanol or formate as carbon sources are considered pathbreaking contributions to solving this global problem. The number of industrially-relevant microorganisms that can use these two carbon sources is limited, and even fewer can concurrently co-assimilate CO2. Here, we search for alternative native methanol and formate assimilation pathways that co-assimilate CO2 in the industrially-relevant methylotrophic yeast Komagataella phaffii (Pichia pastoris). Using 13C-tracer-based metabolomic techniques and metabolic engineering approaches, we discover and confirm a growth supporting pathway based on native enzymes that can perform all three assimilations: namely, the oxygen-tolerant reductive glycine pathway. This finding paves the way towards metabolic engineering of formate and CO2 utilisation to produce proteins, biomass, or chemicals in yeast.
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Affiliation(s)
- Bernd M Mitic
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190, Vienna, Austria
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, Muthgasse 18, 1190, Vienna, Austria
| | - Christina Troyer
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, Muthgasse 18, 1190, Vienna, Austria
| | - Lisa Lutz
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190, Vienna, Austria
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190, Vienna, Austria
| | - Michael Baumschabl
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190, Vienna, Austria
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190, Vienna, Austria
| | - Stephan Hann
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, Muthgasse 18, 1190, Vienna, Austria
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190, Vienna, Austria
| | - Diethard Mattanovich
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Microbiology and Microbial Biotechnology, Muthgasse 18, 1190, Vienna, Austria.
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190, Vienna, Austria.
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3
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Kurt E, Qin J, Williams A, Zhao Y, Xie D. Perspectives for Using CO 2 as a Feedstock for Biomanufacturing of Fuels and Chemicals. Bioengineering (Basel) 2023; 10:1357. [PMID: 38135948 PMCID: PMC10740661 DOI: 10.3390/bioengineering10121357] [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: 10/17/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Microbial cell factories offer an eco-friendly alternative for transforming raw materials into commercially valuable products because of their reduced carbon impact compared to conventional industrial procedures. These systems often depend on lignocellulosic feedstocks, mainly pentose and hexose sugars. One major hurdle when utilizing these sugars, especially glucose, is balancing carbon allocation to satisfy energy, cofactor, and other essential component needs for cellular proliferation while maintaining a robust yield. Nearly half or more of this carbon is inevitably lost as CO2 during the biosynthesis of regular metabolic necessities. This loss lowers the production yield and compromises the benefit of reducing greenhouse gas emissions-a fundamental advantage of biomanufacturing. This review paper posits the perspectives of using CO2 from the atmosphere, industrial wastes, or the exhausted gases generated in microbial fermentation as a feedstock for biomanufacturing. Achieving the carbon-neutral or -negative goals is addressed under two main strategies. The one-step strategy uses novel metabolic pathway design and engineering approaches to directly fix the CO2 toward the synthesis of the desired products. Due to the limitation of the yield and efficiency in one-step fixation, the two-step strategy aims to integrate firstly the electrochemical conversion of the exhausted CO2 into C1/C2 products such as formate, methanol, acetate, and ethanol, and a second fermentation process to utilize the CO2-derived C1/C2 chemicals or co-utilize C5/C6 sugars and C1/C2 chemicals for product formation. The potential and challenges of using CO2 as a feedstock for future biomanufacturing of fuels and chemicals are also discussed.
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Affiliation(s)
- Elif Kurt
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Jiansong Qin
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Alexandria Williams
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Youbo Zhao
- Physical Sciences Inc., 20 New England Business Ctr., Andover, MA 01810, USA;
| | - Dongming Xie
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
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4
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Sullivan SF, Shetty A, Bharadwaj T, Krishna N, Trivedi VD, Endalur Gopinarayanan V, Chappell TC, Sellers DM, Pravin Kumar R, Nair NU. Towards universal synthetic heterotrophy using a metabolic coordinator. Metab Eng 2023; 79:14-26. [PMID: 37406763 PMCID: PMC10529783 DOI: 10.1016/j.ymben.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 06/13/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023]
Abstract
Engineering the utilization of non-native substrates, or synthetic heterotrophy, in proven industrial microbes such as Saccharomyces cerevisiae represents an opportunity to valorize plentiful and renewable sources of carbon and energy as inputs to bioprocesses. We previously demonstrated that activation of the galactose (GAL) regulon, a regulatory structure used by this yeast to coordinate substrate utilization with biomass formation during growth on galactose, during growth on the non-native substrate xylose results in a vastly altered gene expression profile and faster growth compared with constitutive overexpression of the same heterologous catabolic pathway. However, this effort involved the creation of a xylose-inducible variant of Gal3p (Gal3pSyn4.1), the sensor protein of the GAL regulon, preventing this semi-synthetic regulon approach from being easily adapted to additional non-native substrates. Here, we report the construction of a variant Gal3pMC (metabolic coordinator) that exhibits robust GAL regulon activation in the presence of structurally diverse substrates and recapitulates the dynamics of the native system. Multiple molecular modeling studies suggest that Gal3pMC occupies conformational states corresponding to galactose-bound Gal3p in an inducer-independent manner. Using Gal3pMC to test a regulon approach to the assimilation of the non-native lignocellulosic sugars xylose, arabinose, and cellobiose yields higher growth rates and final cell densities when compared with a constitutive overexpression of the same set of catabolic genes. The subsequent demonstration of rapid and complete co-utilization of all three non-native substrates suggests that Gal3pMC-mediated dynamic global gene expression changes by GAL regulon activation may be universally beneficial for engineering synthetic heterotrophy.
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Affiliation(s)
- Sean F Sullivan
- Department of Chemical & Biological Engineering, Tufts University, Medford, MA, 02155, USA
| | - Anuj Shetty
- Kcat Enzymatic Private Limited, Bengaluru, Karnataka, 560005, India
| | - Tharun Bharadwaj
- Kcat Enzymatic Private Limited, Bengaluru, Karnataka, 560005, India
| | - Naveen Krishna
- Kcat Enzymatic Private Limited, Bengaluru, Karnataka, 560005, India
| | - Vikas D Trivedi
- Department of Chemical & Biological Engineering, Tufts University, Medford, MA, 02155, USA; Department of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN, USA
| | | | - Todd C Chappell
- Department of Chemical & Biological Engineering, Tufts University, Medford, MA, 02155, USA
| | - Daniel M Sellers
- Department of Chemical & Biological Engineering, Tufts University, Medford, MA, 02155, USA
| | - R Pravin Kumar
- Kcat Enzymatic Private Limited, Bengaluru, Karnataka, 560005, India
| | - Nikhil U Nair
- Department of Chemical & Biological Engineering, Tufts University, Medford, MA, 02155, USA.
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5
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Qian J, Fan L, Yang J, Feng J, Gao N, Cheng G, Pu W, Zhou W, Cai T, Li S, Zheng P, Sun J, Wang D, Wang Y. Directed evolution of a neutrophilic and mesophilic methanol dehydrogenase based on high-throughput and accurate measurement of formaldehyde. Synth Syst Biotechnol 2023; 8:386-395. [PMID: 37342805 PMCID: PMC10277290 DOI: 10.1016/j.synbio.2023.05.004] [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: 03/20/2023] [Revised: 05/01/2023] [Accepted: 05/21/2023] [Indexed: 06/23/2023] Open
Abstract
Methanol is a promising one-carbon feedstock for biomanufacturing, which can be sustainably produced from carbon dioxide and natural gas. However, the efficiency of methanol bioconversion is limited by the poor catalytic properties of nicotinamide adenine dinucleotide (NAD+)-dependent methanol dehydrogenase (Mdh) that oxidizes methanol to formaldehyde. Herein, the neutrophilic and mesophilic NAD+-dependent Mdh from Bacillus stearothermophilus DSM 2334 (MdhBs) was subjected to directed evolution for enhancing the catalytic activity. The combination of formaldehyde biosensor and Nash assay allowed high-throughput and accurate measurement of formaldehyde and facilitated efficient selection of desired variants. MdhBs variants with up to 6.5-fold higher Kcat/KM value for methanol were screened from random mutation libraries. The T153 residue that is spatially proximal to the substrate binding pocket has significant influence on enzyme activity. The beneficial T153P mutation changes the interaction network of this residue and breaks the α-helix important for substrate binding into two short α-helices. Reconstructing the interaction network of T153 with surrounding residues may represent a promising strategy to further improve MdhBs, and this study provides an efficient strategy for directed evolution of Mdh.
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Affiliation(s)
- Jin Qian
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300222, China
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Liwen Fan
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Jinxing Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Jinhui Feng
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Ning Gao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guimin Cheng
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300222, China
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Wei Pu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Wenjuan Zhou
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Tao Cai
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Shuang Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Ping Zheng
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jibin Sun
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Depei Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300222, China
| | - Yu Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300222, China
- Haihe Laboratory of Synthetic Biology, Tianjin, 300308, China
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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6
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Sarwar A, Lee EY. Methanol-based biomanufacturing of fuels and chemicals using native and synthetic methylotrophs. Synth Syst Biotechnol 2023; 8:396-415. [PMID: 37384124 PMCID: PMC10293595 DOI: 10.1016/j.synbio.2023.06.001] [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: 02/11/2023] [Revised: 06/03/2023] [Accepted: 06/04/2023] [Indexed: 06/30/2023] Open
Abstract
Methanol has recently gained significant attention as a potential carbon substrate for the production of fuels and chemicals, owing to its high degree of reduction, abundance, and low price. Native methylotrophic yeasts and bacteria have been investigated for the production of fuels and chemicals. Alternatively, synthetic methylotrophic strains are also being developed by reconstructing methanol utilization pathways in model microorganisms, such as Escherichia coli. Owing to the complex metabolic pathways, limited availability of genetic tools, and methanol/formaldehyde toxicity, the high-level production of target products for industrial applications are still under development to satisfy commercial feasibility. This article reviews the production of biofuels and chemicals by native and synthetic methylotrophic microorganisms. It also highlights the advantages and limitations of both types of methylotrophs and provides an overview of ways to improve their efficiency for the production of fuels and chemicals from methanol.
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7
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Jia YL, Li J, Nong FT, Yan CX, Ma W, Zhu XF, Zhang LH, Sun XM. Application of Adaptive Laboratory Evolution in Lipid and Terpenoid Production in Yeast and Microalgae. ACS Synth Biol 2023; 12:1396-1407. [PMID: 37084707 DOI: 10.1021/acssynbio.3c00179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
Due to the complexity of metabolic and regulatory networks in microorganisms, it is difficult to obtain robust phenotypes through artificial rational design and genetic perturbation. Adaptive laboratory evolution (ALE) engineering plays an important role in the construction of stable microbial cell factories by simulating the natural evolution process and rapidly obtaining strains with stable traits through screening. This review summarizes the application of ALE technology in microbial breeding, describes the commonly used methods for ALE, and highlights the important applications of ALE technology in the production of lipids and terpenoids in yeast and microalgae. Overall, ALE technology provides a powerful tool for the construction of microbial cell factories, and it has been widely used in improving the level of target product synthesis, expanding the range of substrate utilization, and enhancing the tolerance of chassis cells. In addition, in order to improve the production of target compounds, ALE also employs environmental or nutritional stress strategies corresponding to the characteristics of different terpenoids, lipids, and strains.
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Affiliation(s)
- Yu-Lei Jia
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Jin Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Fang-Tong Nong
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Chun-Xiao Yan
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Wang Ma
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Xiao-Feng Zhu
- College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Li-Hui Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
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8
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Hayes G, Laurel M, MacKinnon D, Zhao T, Houck HA, Becer CR. Polymers without Petrochemicals: Sustainable Routes to Conventional Monomers. Chem Rev 2023; 123:2609-2734. [PMID: 36227737 PMCID: PMC9999446 DOI: 10.1021/acs.chemrev.2c00354] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Access to a wide range of plastic materials has been rationalized by the increased demand from growing populations and the development of high-throughput production systems. Plastic materials at low costs with reliable properties have been utilized in many everyday products. Multibillion-dollar companies are established around these plastic materials, and each polymer takes years to optimize, secure intellectual property, comply with the regulatory bodies such as the Registration, Evaluation, Authorisation and Restriction of Chemicals and the Environmental Protection Agency and develop consumer confidence. Therefore, developing a fully sustainable new plastic material with even a slightly different chemical structure is a costly and long process. Hence, the production of the common plastic materials with exactly the same chemical structures that does not require any new registration processes better reflects the reality of how to address the critical future of sustainable plastics. In this review, we have highlighted the very recent examples on the synthesis of common monomers using chemicals from sustainable feedstocks that can be used as a like-for-like substitute to prepare conventional petrochemical-free thermoplastics.
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Affiliation(s)
- Graham Hayes
- Department of Chemistry, University of Warwick, CV4 7ALCoventry, United Kingdom
| | - Matthew Laurel
- Department of Chemistry, University of Warwick, CV4 7ALCoventry, United Kingdom
| | - Dan MacKinnon
- Department of Chemistry, University of Warwick, CV4 7ALCoventry, United Kingdom
| | - Tieshuai Zhao
- Department of Chemistry, University of Warwick, CV4 7ALCoventry, United Kingdom
| | - Hannes A Houck
- Department of Chemistry, University of Warwick, CV4 7ALCoventry, United Kingdom.,Institute of Advanced Study, University of Warwick, CV4 7ALCoventry, United Kingdom
| | - C Remzi Becer
- Department of Chemistry, University of Warwick, CV4 7ALCoventry, United Kingdom
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9
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Bruinsma L, Wenk S, Claassens NJ, Martins Dos Santos VAP. Paving the way for synthetic C1 - Metabolism in Pseudomonas putida through the reductive glycine pathway. Metab Eng 2023; 76:215-224. [PMID: 36804222 DOI: 10.1016/j.ymben.2023.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 02/10/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023]
Abstract
One-carbon (C1) compounds such as methanol, formate, and CO2 are alternative, sustainable microbial feedstocks for the biobased production of chemicals and fuels. In this study, we engineered the carbon metabolism of the industrially important bacterium Pseudomonas putida to modularly assimilate these three substrates through the reductive glycine pathway. First, we demonstrated the functionality of the C1-assimilation module by coupling the growth of auxotrophic strains to formate assimilation. Next, we extended the module in the auxotrophic strains from formate to methanol-dependent growth using both NAD and PQQ-dependent methanol dehydrogenases. Finally, we demonstrated, for the first time, engineered CO2-dependent formation of part of the biomass through CO2 reduction to formate by the native formate dehydrogenase, which required short-term evolution to rebalance the cellular NADH/NAD + ratio. This research paves the way to further engineer P. putida towards full growth on formate, methanol, and CO2 as sole feedstocks, thereby substantially expanding its potential as a sustainable and versatile cell factory.
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Affiliation(s)
- Lyon Bruinsma
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, 6708, WE, the Netherlands
| | - Sebastian Wenk
- Systems and Synthetic Metabolism Group, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Nico J Claassens
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, 6708, WE, the Netherlands.
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, 6708, WE, the Netherlands; LifeGlimmer GmbH, Berlin, 12163, Germany; Bioprocess Engineering, Wageningen University & Research, Wageningen, 6708, WE, the Netherlands.
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10
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Orsi E, Claassens NJ, Nikel PI, Lindner SN. Optimizing microbial networks through metabolic bypasses. Biotechnol Adv 2022; 60:108035. [PMID: 36096403 DOI: 10.1016/j.biotechadv.2022.108035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 01/29/2023]
Abstract
Metabolism has long been considered as a relatively stiff set of biochemical reactions. This somewhat outdated and dogmatic view has been challenged over the last years, as multiple studies exposed unprecedented plasticity of metabolism by exploring rational and evolutionary modifications within the metabolic network of cell factories. Of particular importance is the emergence of metabolic bypasses, which consist of enzymatic reaction(s) that support unnatural connections between metabolic nodes. Such novel topologies can be generated through the introduction of heterologous enzymes or by upregulating native enzymes (sometimes relying on promiscuous activities thereof). Altogether, the adoption of bypasses resulted in an expansion in the capacity of the host's metabolic network, which can be harnessed for bioproduction. In this review, we discuss modifications to the canonical architecture of central carbon metabolism derived from such bypasses towards six optimization purposes: stoichiometric gain, overcoming kinetic limitations, solving thermodynamic barriers, circumventing toxic intermediates, uncoupling product synthesis from biomass formation, and altering redox cofactor specificity. The metabolic costs associated with bypass-implementation are likewise discussed, including tailoring their design towards improving bioproduction.
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Affiliation(s)
- Enrico Orsi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
| | - Nico J Claassens
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, the Netherlands
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Steffen N Lindner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; Department of Biochemistry, Charité Universitätsmedizin, Virchowweg 6, 10117 Berlin, Germany.
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11
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Wegat V, Fabarius JT, Sieber V. Synthetic methylotrophic yeasts for the sustainable fuel and chemical production. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:113. [PMID: 36273178 PMCID: PMC9587593 DOI: 10.1186/s13068-022-02210-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/25/2022] [Indexed: 11/13/2022]
Abstract
Global energy-related emissions, in particular carbon dioxide, are rapidly increasing. Without immediate and strong reductions across all sectors, limiting global warming to 1.5 °C and thus mitigating climate change is beyond reach. In addition to the expansion of renewable energies and the increase in energy efficiency, the so-called Carbon Capture and Utilization technologies represent an innovative approach for closing the carbon cycle and establishing a circular economy. One option is to combine CO2 capture with microbial C1 fermentation. C1-molecules, such as methanol or formate are considered as attractive alternative feedstock for biotechnological processes due to their sustainable production using only CO2, water and renewable energy. Native methylotrophic microorganisms can utilize these feedstock for the production of value-added compounds. Currently, constraints exist regarding the understanding of methylotrophic metabolism and the available genetic engineering tools are limited. For this reason, the development of synthetic methylotrophic cell factories based on the integration of natural or artificial methanol assimilation pathways in biotechnologically relevant microorganisms is receiving special attention. Yeasts like Saccharomyces cerevisiae and Yarrowia lipolytica are capable of producing important products from sugar-based feedstock and the switch to produce these in the future from methanol is important in order to realize a CO2-based economy that is independent from land use. Here, we review historical biotechnological applications, the metabolism and the characteristics of methylotrophic yeasts. Various studies demonstrated the production of a broad set of promising products from fine chemicals to bulk chemicals by applying methylotrophic yeasts. Regarding synthetic methylotrophy, the deep understanding of the methylotrophic metabolism serves as the basis for microbial strain engineering and paves the way towards a CO2-based circular bioeconomy. We highlight design aspects of synthetic methylotrophy and discuss the resulting chances and challenges using non-conventional yeasts as host organisms. We conclude that the road towards synthetic methylotrophic yeasts can only be achieved through a combination of methods (e.g., metabolic engineering and adaptive laboratory evolution). Furthermore, we presume that the installation of metabolic regeneration cycles such as supporting carbon re-entry towards the pentose phosphate pathway from C1-metabolism is a pivotal target for synthetic methylotrophy.
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Affiliation(s)
- Vanessa Wegat
- grid.469831.10000 0000 9186 607XFraunhofer Institute for Interfacial Engineering and Biotechnology, Straubing branch Biocat, Schulgasse 11a, 94315 Straubing, Germany ,grid.6936.a0000000123222966Technical University of Munich, Campus Straubing for Biotechnology and Sustainability, Schulgasse 16, 94315 Straubing, Germany
| | - Jonathan T. Fabarius
- grid.469831.10000 0000 9186 607XFraunhofer Institute for Interfacial Engineering and Biotechnology, Straubing branch Biocat, Schulgasse 11a, 94315 Straubing, Germany
| | - Volker Sieber
- grid.469831.10000 0000 9186 607XFraunhofer Institute for Interfacial Engineering and Biotechnology, Straubing branch Biocat, Schulgasse 11a, 94315 Straubing, Germany ,grid.6936.a0000000123222966Technical University of Munich, Campus Straubing for Biotechnology and Sustainability, Schulgasse 16, 94315 Straubing, Germany
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12
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Keller P, Reiter MA, Kiefer P, Gassler T, Hemmerle L, Christen P, Noor E, Vorholt JA. Generation of an Escherichia coli strain growing on methanol via the ribulose monophosphate cycle. Nat Commun 2022; 13:5243. [PMID: 36068201 PMCID: PMC9448777 DOI: 10.1038/s41467-022-32744-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022] Open
Abstract
Methanol is a liquid with high energy storage capacity that holds promise as an alternative substrate to replace sugars in the biotechnology industry. It can be produced from CO2 or methane and its use does not compete with food and animal feed production. However, there are currently only limited biotechnological options for the valorization of methanol, which hinders its widespread adoption. Here, we report the conversion of the industrial platform organism Escherichia coli into a synthetic methylotroph that assimilates methanol via the energy efficient ribulose monophosphate cycle. Methylotrophy is achieved after evolution of a methanol-dependent E. coli strain over 250 generations in continuous chemostat culture. We demonstrate growth on methanol and biomass formation exclusively from the one-carbon source by 13C isotopic tracer analysis. In line with computational modeling, the methylotrophic E. coli strain optimizes methanol oxidation by upregulation of an improved methanol dehydrogenase, increasing ribulose monophosphate cycle activity, channeling carbon flux through the Entner-Doudoroff pathway and downregulating tricarboxylic acid cycle enzymes. En route towards sustainable bioproduction processes, our work lays the foundation for the efficient utilization of methanol as the dominant carbon and energy resource. Using one carbon compounds as feedstock is a promising approach in abating climate change. Here, the authors report the conversion of E. coli into a synthetic methylotroph that assimilates methanol via the ribulose monophosphate cycle and a set of distinctive mutations.
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Affiliation(s)
- Philipp Keller
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Michael A Reiter
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Patrick Kiefer
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Thomas Gassler
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Lucas Hemmerle
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland.,Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Philipp Christen
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Elad Noor
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Julia A Vorholt
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland.
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13
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Efficient fatty acid synthesis from methanol in methylotrophic yeast. Synth Syst Biotechnol 2022; 7:1183-1184. [PMID: 36262715 PMCID: PMC9574570 DOI: 10.1016/j.synbio.2022.09.003] [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: 08/09/2022] [Revised: 09/22/2022] [Accepted: 09/25/2022] [Indexed: 11/24/2022] Open
Abstract
Methanol is an attractive C1 feedstock with high abundance and low cost in bio-manufacturing. However, the metabolic construction of cell factories to utilize methanol for chemicals production remains a challenge due to the toxic intermediates and complicated metabolic pathways. The group of Zhou rescued methylotrophic yeast from cell death and achieved high-level production of free fatty acids from methanol through a combination of adaptive laboratory evolution, rational metabolic engineering and multi-omics analysis.
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14
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Kelso PA, Chow LKM, Carpenter AC, Paulsen IT, Williams TC. Toward Methanol-Based Biomanufacturing: Emerging Strategies for Engineering Synthetic Methylotrophy in Saccharomyces cerevisiae. ACS Synth Biol 2022; 11:2548-2563. [PMID: 35848307 DOI: 10.1021/acssynbio.2c00110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The global expansion of biomanufacturing is currently limited by the availability of sugar-based microbial feedstocks, which require farmland for cultivation and therefore cannot support large increases in production without impacting the human food supply. One-carbon feedstocks, such as methanol, present an enticing alternative to sugar because they can be produced independently of arable farmland from organic waste, atmospheric carbon dioxide, and hydrocarbons such as biomethane, natural gas, and coal. The development of efficient industrial microorganisms that can convert one-carbon feedstocks into valuable products is an ongoing challenge. This review discusses progress in the field of synthetic methylotrophy with a focus on how it pertains to the important industrial yeast, Saccharomyces cerevisiae. Recent insights generated from engineering synthetic methylotrophic xylulose- and ribulose-monophosphate cycles, reductive glycine pathways, and adaptive laboratory evolution studies are critically assessed to generate novel strategies for the future engineering of methylotrophy in S. cerevisiae.
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Affiliation(s)
- Philip A Kelso
- School of Natural Sciences, and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Macquarie Park, Sydney, NSW 2109, Australia
| | | | - Alex C Carpenter
- School of Natural Sciences, and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Macquarie Park, Sydney, NSW 2109, Australia
| | - Ian T Paulsen
- School of Natural Sciences, and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Macquarie Park, Sydney, NSW 2109, Australia
| | - Thomas C Williams
- School of Natural Sciences, and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Macquarie Park, Sydney, NSW 2109, Australia
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15
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Onyeaka H, Ekwebelem OC. A review of recent advances in engineering bacteria for enhanced CO 2 capture and utilization. INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY : IJEST 2022; 20:4635-4648. [PMID: 35755182 PMCID: PMC9207427 DOI: 10.1007/s13762-022-04303-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 04/12/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Carbon dioxide (CO2) is emitted into the atmosphere due to some anthropogenic activities, such as the combustion of fossil fuels and industrial output. As a result, fears about catastrophic global warming and climate change have intensified. In the face of these challenges, conventional CO2 capture technologies are typically ineffective, dangerous, and contribute to secondary pollution in the environment. Biological systems for CO2 conversion, on the other hand, provide a potential path forward owing to its high application selectivity and adaptability. Moreover, many bacteria can use CO2 as their only source of carbon and turn it into value-added products. The purpose of this review is to discuss recent significant breakthroughs in engineering bacteria to utilize CO2 and other one-carbon compounds as substrate. In the same token, the paper also summarizes and presents aspects such as microbial CO2 fixation pathways, engineered bacteria involved in CO2 fixation, up-to-date genetic and metabolic engineering approaches for CO2 fixation, and promising research directions for the production of value-added products from CO2. This review's findings imply that using biological systems like modified bacteria to manage CO2 has the added benefit of generating useful industrial byproducts like biofuels, pharmaceutical compounds, and bioplastics. The major downside, from an economic standpoint, thus far has been related to methods of cultivation. However, thanks to genetic engineering approaches, this can be addressed by large production yields. As a result, this review aids in the knowledge of various biological systems that can be used to construct a long-term CO2 mitigation technology at an industrial scale, in this instance bacteria-based CO2capture/utilization technology.
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Affiliation(s)
- H. Onyeaka
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | - O. C. Ekwebelem
- Faculty of Biological Sciences, University of Nigeria, Nsukka, 410001 Nigeria
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16
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Hoyt KO, Woolston BM. Adapting isotopic tracer and metabolic flux analysis approaches to study C1 metabolism. Curr Opin Biotechnol 2022; 75:102695. [PMID: 35182834 DOI: 10.1016/j.copbio.2022.102695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 12/20/2022]
Abstract
Single-carbon (C1, or one-carbon) substrates are promising feedstocks for sustainable biofuel and biochemical production. Crucial to the goal of engineering C1-utilizing strains for improved production is a quantitative understanding of the organization, regulation and rates of the reactions that underpin C1 metabolism. 13C Metabolic flux analysis (MFA) is a well-established platform for interrogating these questions with multi-carbon substrates, and uses the differential labeling of metabolites that results from feeding a substrate with position-specific incorporation of 13C in order to infer quantitative fluxes and pathway topology. Adapting isotopic tracer approaches to C1 metabolism, where position-specific substrate labeling is impossible, requires additional experimental considerations. Here we review recent studies that have developed isotopic tracer approaches to overcome the challenge of uniform metabolite labeling and provide quantitative insight into C1 metabolism.
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Affiliation(s)
- Kathryn O Hoyt
- Department of Chemical Engineering, 201 Cullinane, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA
| | - Benjamin M Woolston
- Department of Chemical Engineering, 201 Cullinane, Northeastern University, 360 Huntington Avenue, Boston, MA 02115-5000, USA.
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17
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Partial Methane Oxidation in Fuel Cell-Type Reactors for Co-Generation of Energy and Chemicals: A Short Review. Catalysts 2022. [DOI: 10.3390/catal12020217] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The conversion of methane into chemicals is of interest to achieve a decarbonized future. Fuel cells are electrochemical devices commonly used to obtain electrical energy but can be utilized either for chemicals’ production or both energy and chemicals cogeneration. In this work, the partial oxidation of methane in fuel cells for electricity generation and valuable chemicals production at the same time is reviewed. For this purpose, we compile different types of methane-fed fuel cells, both low- and high-temperature fuel cells. Despite the fact that few studies have been conducted on this subject, promising results are driving the development of fuel cells that use methane as a fuel source for the cogeneration of power and valuable chemicals.
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18
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Gao B, Zhao N, Deng J, Gu Y, Jia S, Hou Y, Lv X, Liu L. Constructing a methanol-dependent Bacillus subtilis by engineering the methanol metabolism. J Biotechnol 2022; 343:128-137. [PMID: 34906603 DOI: 10.1016/j.jbiotec.2021.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 12/05/2021] [Accepted: 12/08/2021] [Indexed: 12/22/2022]
Abstract
Methanol is a promising green feedstock for producing fuels and chemicals because it is inexpensive, clean, environmentally friendly, and easily prepared. Thus, many studies have been devoted to engineering non-native methylotrophic platform microorganisms to utilize methanol. This study adopted a series of strategies to develop a synthetic methylotrophic Bacillus subtilis that can use methanol as the carbon source, including the heterologous expression of methanol dehydrogenase (Mdh), enhancement of the expressions of 3-hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi), regulation of the expressions of key enzymes at both the translational and transcriptional levels, stabilization of the key enzyme expression through a dual-system for expressing the target genes on both the plasmid and genome, and improvement of the catalytic activity of Mdh with a recycling strategy for NAD+. As a result, the methanol consumption of the synthetic methylotrophic B. subtilis reached 4.09 g/L, with the maximum OD600 showing a 2.21-fold increase compared with the wild-type B. subtilis, which cannot use methanol. We further deleted the phosphoglucose isomerase (Pgi) and added co-substrates to increase the supply of ribulose-5-phosphate (Ru-5-P), and the specific methanol consumption rate increased by an additional 27.54%. Finally, we successfully constructed two strains that cannot grow in M9 medium with xylose or ribose unless methanol is utilized. The strategies used in this study are generally applicable to other studies on synthetic methylotrophy.
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Affiliation(s)
- Bo Gao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Ning Zhao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Jieying Deng
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Yang Gu
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Shiru Jia
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Ying Hou
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin 300457, China; Tianjin Tianlong Agricultural Science and Technology Co., Ltd, Tianjin 300457, China.
| | - Xueqin Lv
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Long Liu
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
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19
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Wang Y, Zheng P, Sun J. Developing Synthetic Methylotrophs by Metabolic Engineering-Guided Adaptive Laboratory Evolution. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2022; 180:127-148. [DOI: 10.1007/10_2021_185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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20
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Sanford PA, Woolston BM. Synthetic or natural? Metabolic engineering for assimilation and valorization of methanol. Curr Opin Biotechnol 2021; 74:171-179. [PMID: 34952430 DOI: 10.1016/j.copbio.2021.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 11/23/2021] [Accepted: 12/01/2021] [Indexed: 01/01/2023]
Abstract
Single carbon (C1) substrates such as methanol are gaining increasing attention as cost-effective and environmentally friendly microbial feedstocks. Recent impressive metabolic engineering efforts to import C1 catabolic pathways into the non-methylotrophic bacterium Escherichia coli have led to synthetic strains growing on methanol as the sole carbon source. However, the growth rate and product yield in these strains remain inferior to native methylotrophs. Meanwhile, an ever-expanding genetic engineering toolbox is increasing the tractability of native C1 utilizers, raising the question of whether it is best to use an engineered strain or a native host for the microbial assimilation of C1 substrates. Here we provide perspective on this debate, using recent work in E. coli and the methylotrophic acetogen Eubacterium limosum as case studies.
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Affiliation(s)
- Patrick A Sanford
- Northeastern University, Department of Chemical Engineering, 360 Huntington Avenue, 223 Cullinane, United States
| | - Benjamin M Woolston
- Northeastern University, Department of Chemical Engineering, 360 Huntington Avenue, 223 Cullinane, United States.
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21
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García JL, Galán B. Integrating greenhouse gas capture and C1 biotechnology: a key challenge for circular economy. Microb Biotechnol 2021; 15:228-239. [PMID: 34905295 PMCID: PMC8719819 DOI: 10.1111/1751-7915.13991] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 12/02/2022] Open
Affiliation(s)
- José L García
- Environmental Biotechnology Laboratory, Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas (CIB-MS, CSIC), Madrid, Spain
| | - Beatriz Galán
- Environmental Biotechnology Laboratory, Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas (CIB-MS, CSIC), Madrid, Spain
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22
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Bioconversion of Methanol by Synthetic Methylotrophy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 180:149-168. [PMID: 34545421 DOI: 10.1007/10_2021_176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
As an important building block in the chemical industry, methanol has become an attractive substrate in biorefinery owing to its abundance and low cost. With the development of synthetic biology, metabolic engineering of non-methylotrophy to construct synthetic methylotrophy has drawn increased attention. As for the metabolic construction of methanol assimilation pathway in some industrial hosts, several artificial methanol assimilation pathways have recently been designed and constructed based on the computer-aided design. Particularly, these artificial methanol assimilation pathways possess advantages of shorter reaction steps, stronger driving forces, and independence on oxygen. Accordingly, this chapter reviewed strategies of constructing synthetic methylotrophs, including introducing methanol metabolic modules derived from natural methylotrophs and designing artificial methanol assimilation pathways. Future challenges and prospects were also discussed.
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23
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Gregory GJ, Bennett RK, Papoutsakis ET. Recent advances toward the bioconversion of methane and methanol in synthetic methylotrophs. Metab Eng 2021; 71:99-116. [PMID: 34547453 DOI: 10.1016/j.ymben.2021.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/14/2021] [Accepted: 09/16/2021] [Indexed: 12/19/2022]
Abstract
Abundant natural gas reserves, along with increased biogas production, have prompted recent interest in harnessing methane as an industrial feedstock for the production of liquid fuels and chemicals. Methane can either be used directly for fermentation or first oxidized to methanol via biological or chemical means. Methanol is advantageous due to its liquid state under normal conditions. Methylotrophy, defined as the ability of microorganisms to utilize reduced one-carbon compounds like methane and methanol as sole carbon and energy sources for growth, is widespread in bacterial communities. However, native methylotrophs lack the extensive and well-characterized synthetic biology toolbox of platform microorganisms like Escherichia coli, which results in slow and inefficient design-build-test cycles. If a heterologous production pathway can be engineered, the slow growth and uptake rates of native methylotrophs generally limit their industrial potential. Therefore, much focus has been placed on engineering synthetic methylotrophs, or non-methylotrophic platform microorganisms, like E. coli, that have been engineered with synthetic methanol utilization pathways. These platform hosts allow for rapid design-build-test cycles and are well-suited for industrial application at the current time. In this review, recent progress made toward synthetic methylotrophy (including methanotrophy) is discussed. Specifically, the importance of amino acid metabolism and alternative one-carbon assimilation pathways are detailed. A recent study that has achieved methane bioconversion to liquid chemicals in a synthetic E. coli methanotroph is also briefly discussed. We also discuss strategies for the way forward in order to realize the industrial potential of synthetic methanotrophs and methylotrophs.
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Affiliation(s)
- Gwendolyn J Gregory
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - R Kyle Bennett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
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24
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Gruenberg M, Irla M, Myllek S, Draths K. Characterization of two 3-deoxy-d-Arabino-Heptulosonate 7-phosphate synthases from Bacillusmethanolicus. Protein Expr Purif 2021; 188:105972. [PMID: 34517109 DOI: 10.1016/j.pep.2021.105972] [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: 06/28/2021] [Revised: 08/23/2021] [Accepted: 09/07/2021] [Indexed: 10/20/2022]
Abstract
3-Deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase catalyzes the condensation of phosphoenolpyruvate (PEP) with d-erythrose 4-phosphate (E4P) and plays an important role in regulating carbon flux toward aromatic amino acid biosynthesis in bacteria and plants. Sequence analysis of the DAHP synthases AroG1 and AroG2 from Bacillus methanolicus MGA3 suggested this thermophilic, methylotrophic bacterium possesses two type Iβ DAHP synthases. This study describes production of AroG1 and AroG2 in Escherichia coli as hexa-histidine fused proteins, which were purified by affinity chromatography. Treatment with TEV protease afforded native proteins for characterization and kinetic analysis. AroG1 and AroG2 are, respectively, 30.1 kDa and 40.0 kDa proteins. Both enzymes have maximal activity over a pH range of 6.3-7.2. The apparent kinetic parameters at 50 °C and pH 7.2 for AroG1 are KmPEP 1100 ± 100 μM, KmE4P 530 ± 100 μM, and kcat 10.3 ± 1.2 s-1. The kinetic parameters for AroG2 are KmPEP 90 ± 20 μM, KmE4P 130 ± 40 μM, and kcat 2.0 ± 0.2 s-1. At 50 °C AroG2 retains 50% of its activity after 96 min whereas AroG1 retains less than 5% of its activity after 10 min. AroG2, which contains an N-terminal regulatory domain, is inhibited by chorismate and prephenate but not l-phenylalanine, l-tyrosine, or l-tryptophan. AroG1 is not inhibited by any of the molecules examined. Understanding DAHP synthase regulation in B. methanolicus is a first step toward generating biocatalysts that exploit the target-rich aromatic amino acid biosynthetic pathway for synthesis of chemicals from methanol.
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Affiliation(s)
- Megan Gruenberg
- Department of Chemistry, 578 S. Shaw Lane, Michigan State University, East Lansing, MI, 48824, USA.
| | - Marta Irla
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway.
| | - Sebastian Myllek
- Department of Chemistry, 578 S. Shaw Lane, Michigan State University, East Lansing, MI, 48824, USA.
| | - Karen Draths
- Department of Chemistry, 578 S. Shaw Lane, Michigan State University, East Lansing, MI, 48824, USA.
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25
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Cai H, Doi R, Shimada M, Hayakawa T, Nakagawa T. Metabolic regulation adapting to high methanol environment in the methylotrophic yeast Ogataea methanolica. Microb Biotechnol 2021; 14:1512-1524. [PMID: 33939325 PMCID: PMC8313246 DOI: 10.1111/1751-7915.13811] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 11/28/2022] Open
Abstract
Since methylotrophic yeasts such as Ogataea methanolica can use methanol as a sole carbon feedstock, they could be applied to produce valuable products from methanol, a next-generation energy source synthesized from natural gases, using genetic engineering tools. In this study, metabolite profiling of O. methanolica was conducted under glucose (Glc) and low and high methanol (L- and H-MeOH) conditions to show the adaptation mechanism to a H-MeOH environment. The yeast strain responded not only to the presence of methanol but also to its concentration based on the growth condition. Under H-MeOH conditions, O. methanolica downregulated the methanol utilization, glycolytic pathway and alcohol oxidase (AOD) isozymes and dihydroxyacetone synthase (DAS) expression compared with L-MeOH-grown cells. However, levels of energy carriers, such as ATP, were maintained to support cell survival. In H-MeOH-grown cells, reactive oxygen species (ROS) levels were significantly elevated. Along with increasing ROS levels, ROS scavenging system expression was significantly increased in H-MeOH-grown cells. Thus, we concluded that formaldehyde and H2 O2 , which are products of methanol oxidation by AOD isozymes in the peroxisome, are overproduced in H-MeOH-grown cells, and excessive ROS derived from these cells is generated in the cytosol, resulting in upregulation of the antioxidant system and downregulation of the methanol-utilizing pathway to suppress overproduction of toxic intermediates.
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Affiliation(s)
- Hao‐Liang Cai
- The United Graduate School of Agricultural ScienceGifu University1‐1 YanagidoGifu501‐1193Japan
| | - Ryohei Doi
- The Graduate School of Natural Sciences and Technologies1‐1 YanagidoGifu501‐1193Japan
| | - Masaya Shimada
- The United Graduate School of Agricultural ScienceGifu University1‐1 YanagidoGifu501‐1193Japan
- The Graduate School of Natural Sciences and Technologies1‐1 YanagidoGifu501‐1193Japan
- The Faculty of Applied Biological Sciences1‐1 YanagidoGifu501‐1193Japan
| | - Takashi Hayakawa
- The United Graduate School of Agricultural ScienceGifu University1‐1 YanagidoGifu501‐1193Japan
- The Graduate School of Natural Sciences and Technologies1‐1 YanagidoGifu501‐1193Japan
- The Faculty of Applied Biological Sciences1‐1 YanagidoGifu501‐1193Japan
| | - Tomoyuki Nakagawa
- The United Graduate School of Agricultural ScienceGifu University1‐1 YanagidoGifu501‐1193Japan
- The Graduate School of Natural Sciences and Technologies1‐1 YanagidoGifu501‐1193Japan
- The Faculty of Applied Biological Sciences1‐1 YanagidoGifu501‐1193Japan
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26
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Meng H, Wang C, Yuan Q, Ren J, Zeng AP. An Aldolase-Based New Pathway for Bioconversion of Formaldehyde and Ethanol into 1,3-Propanediol in Escherichia coli. ACS Synth Biol 2021; 10:799-809. [PMID: 33729768 DOI: 10.1021/acssynbio.0c00597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Formaldehyde (HCHO) is a reactive one-carbon compound that is interesting for biosynthesis. The assimilation of HCHO depends on the catalysis of aldolase. Here, we present a novel synthetic pathway in E. coli to convert HCHO and ethanol into 1,3-propanediol (PDO) using a deoxyribose-5-phosphate aldolase (DERA). DERA condenses HCHO and acetaldehyde to form 3-hydroxypropionaldehyde, the direct precursor of PDO formation. This new pathway opens up the possibility to synthesize an appealing C3 compound from a C1 compound and a C2 compound without carbon loss in contrast to all the other known PDO synthetic pathways where typically 30-50% of the carbons are lost as CO2 and other byproducts. The pathway is successfully demonstrated by elaborating three metabolic modules. First, DERA from Thermotoga maritima was found to be efficient for the aldol condensation and PDO production module. For the module of acetaldehyde supply from ethanol, an alcohol dehydrogenase from Hansenula polymorpha was selected. For the HCHO supply module, the control of HCHO concentration and its utilization were shown to be important for achieving the assimilation of HCHO in recombinant E. coli cells. By deleting the gene frmA for endogenous conversion of HCHO to formate and controlling HCHO at a level of about 0.6 mM, the concentration and yield of PDO were increased from initially 5.67 mM (0.43 g/L) and 0.057 mol/mol to 17.35 mM (1.32 g/L) and 0.096 mol/mol in bioconversion of ethanol and HCHO with resting E. coli cells. Further engineering of DERA and the HCHO supply module is necessary to realize the potential of this promising metabolic pathway.
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Affiliation(s)
- Hao Meng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, North Third Ring Road 15, 100029 Beijing, China
| | - Chuang Wang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, North Third Ring Road 15, 100029 Beijing, China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 100029 Beijing, China
| | - Jie Ren
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, North Third Ring Road 15, 100029 Beijing, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests/Key Laboratory of Control of Biological Hazard Factors (Plant Origin) for Agriproduct Quality and Safety, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - An-Ping Zeng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, North Third Ring Road 15, 100029 Beijing, China
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Denickestrasse 15, D-21073 Hamburg, Germany
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27
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Khider MLK, Brautaset T, Irla M. Methane monooxygenases: central enzymes in methanotrophy with promising biotechnological applications. World J Microbiol Biotechnol 2021; 37:72. [PMID: 33765207 PMCID: PMC7994243 DOI: 10.1007/s11274-021-03038-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/09/2021] [Indexed: 12/02/2022]
Abstract
Worldwide, the use of methane is limited to generating power, electricity, heating, and for production of chemicals. We believe this valuable gas can be employed more widely. Here we review the possibility of using methane as a feedstock for biotechnological processes based on the application of synthetic methanotrophs. Methane monooxygenase (MMO) enables aerobic methanotrophs to utilize methane as a sole carbon and energy source, in contrast to industrial microorganisms that grow on carbon sources, such as sugar cane, which directly compete with the food market. However, naturally occurring methanotrophs have proven to be difficult to manipulate genetically and their current industrial use is limited to generating animal feed biomass. Shifting the focus from genetic engineering of methanotrophs, towards introducing metabolic pathways for methane utilization in familiar industrial microorganisms, may lead to construction of efficient and economically feasible microbial cell factories. The applications of a technology for MMO production are not limited to methane-based industrial synthesis of fuels and value-added products, but are also of interest in bioremediation where mitigating anthropogenic pollution is an increasingly relevant issue. Published research on successful functional expression of MMO does not exist, but several attempts provide promising future perspectives and a few recent patents indicate that there is an ongoing research in this field. Combining the knowledge on genetics and metabolism of methanotrophy with tools for functional heterologous expression of MMO-encoding genes in non-methanotrophic bacterial species, is a key step for construction of synthetic methanotrophs that holds a great biotechnological potential.
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Affiliation(s)
- May L K Khider
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Trygve Brautaset
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Marta Irla
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway.
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28
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Bennett RK, Gregory GJ, Gonzalez JE, Har JRG, Antoniewicz MR, Papoutsakis ET. Improving the Methanol Tolerance of an Escherichia coli Methylotroph via Adaptive Laboratory Evolution Enhances Synthetic Methanol Utilization. Front Microbiol 2021; 12:638426. [PMID: 33643274 PMCID: PMC7904680 DOI: 10.3389/fmicb.2021.638426] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 01/21/2021] [Indexed: 02/05/2023] Open
Abstract
There is great interest in developing synthetic methylotrophs that harbor methane and methanol utilization pathways in heterologous hosts such as Escherichia coli for industrial bioconversion of one-carbon compounds. While there are recent reports that describe the successful engineering of synthetic methylotrophs, additional efforts are required to achieve the robust methylotrophic phenotypes required for industrial realization. Here, we address an important issue of synthetic methylotrophy in E. coli: methanol toxicity. Both methanol, and its oxidation product, formaldehyde, are cytotoxic to cells. Methanol alters the fluidity and biological properties of cellular membranes while formaldehyde reacts readily with proteins and nucleic acids. Thus, efforts to enhance the methanol tolerance of synthetic methylotrophs are important. Here, adaptive laboratory evolution was performed to improve the methanol tolerance of several E. coli strains, both methylotrophic and non-methylotrophic. Serial batch passaging in rich medium containing toxic methanol concentrations yielded clones exhibiting improved methanol tolerance. In several cases, these evolved clones exhibited a > 50% improvement in growth rate and biomass yield in the presence of high methanol concentrations compared to the respective parental strains. Importantly, one evolved clone exhibited a two to threefold improvement in the methanol utilization phenotype, as determined via 13C-labeling, at non-toxic, industrially relevant methanol concentrations compared to the respective parental strain. Whole genome sequencing was performed to identify causative mutations contributing to methanol tolerance. Common mutations were identified in 30S ribosomal subunit proteins, which increased translational accuracy and provided insight into a novel methanol tolerance mechanism. This study addresses an important issue of synthetic methylotrophy in E. coli and provides insight as to how methanol toxicity can be alleviated via enhancing methanol tolerance. Coupled improvement of methanol tolerance and synthetic methanol utilization is an important advancement for the field of synthetic methylotrophy.
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Affiliation(s)
- R Kyle Bennett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States.,Molecular Biotechnology Laboratory, The Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
| | - Gwendolyn J Gregory
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States.,Molecular Biotechnology Laboratory, The Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
| | - Jacqueline E Gonzalez
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Jie Ren Gerald Har
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States.,Molecular Biotechnology Laboratory, The Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
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29
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Wang X, Gao S, Wang J, Xu S, Li H, Chen K, Ouyang P. The production of biobased diamines from renewable carbon sources: Current advances and perspectives. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2020.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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30
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Adaptive laboratory evolution of methylotrophic Escherichia coli enables synthesis of all amino acids from methanol-derived carbon. Appl Microbiol Biotechnol 2021; 105:869-876. [PMID: 33404828 DOI: 10.1007/s00253-020-11058-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 09/21/2020] [Accepted: 12/10/2020] [Indexed: 02/07/2023]
Abstract
Recent attempts to create synthetic Escherichia coli methylotrophs identified that de novo biosynthesis of amino acids, in the presence of methanol, presents significant challenges in achieving autonomous methylotrophic growth. Previously engineered methanol-dependent strains required co-utilization of stoichiometric amounts of co-substrates and methanol. As such, these strains could not be evolved to grow on methanol alone. In this work, we have explored an alternative approach to enable biosynthesis of all amino acids from methanol-derived carbon in minimal media without stoichiometric coupling. First, we identified that biosynthesis of threonine was limiting the growth of our methylotrophic E. coli. To address this, we performed adaptive laboratory evolution to generate a strain that grew efficiently in minimal medium with methanol and threonine. Methanol assimilation and growth of the evolved strain were analyzed, and, interestingly, we found that the evolved strain synthesized all amino acids, including threonine, from methanol-derived carbon. The evolved strain was then further engineered through overexpression of an optimized threonine biosynthetic pathway. We show that the resulting methylotrophic E. coli strain has a methanol-dependent growth phenotype with homoserine as co-substrate. In contrast to previous methanol-dependent strains, co-utilization of homoserine is not stoichiometrically linked to methanol assimilation. As such, future engineering of this strain and successive adaptive evolution could enable autonomous growth on methanol as the sole carbon source. KEY POINTS: • Adaptive evolution of E. coli enables biosynthesis of all amino acids from methanol. • Overexpression of threonine biosynthesis pathway improves methanol assimilation. • Methanol-dependent growth is seen in minimal media with homoserine as co-substrate.
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31
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Zhang B, Jiang Y, Li Z, Wang F, Wu XY. Recent Progress on Chemical Production From Non-food Renewable Feedstocks Using Corynebacterium glutamicum. Front Bioeng Biotechnol 2021; 8:606047. [PMID: 33392171 PMCID: PMC7775722 DOI: 10.3389/fbioe.2020.606047] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/31/2020] [Indexed: 11/13/2022] Open
Abstract
Due to the non-renewable nature of fossil fuels, microbial fermentation is considered a sustainable approach for chemical production using glucose, xylose, menthol, and other complex carbon sources represented by lignocellulosic biomass. Among these, xylose, methanol, arabinose, glycerol, and other alternative feedstocks have been identified as superior non-food sustainable carbon substrates that can be effectively developed for microbe-based bioproduction. Corynebacterium glutamicum is a model gram-positive bacterium that has been extensively engineered to produce amino acids and other chemicals. Recently, in order to reduce production costs and avoid competition for human food, C. glutamicum has also been engineered to broaden its substrate spectrum. Strengthening endogenous metabolic pathways or assembling heterologous ones enables C. glutamicum to rapidly catabolize a multitude of carbon sources. This review summarizes recent progress in metabolic engineering of C. glutamicum toward a broad substrate spectrum and diverse chemical production. In particularly, utilization of lignocellulosic biomass-derived complex hybrid carbon source represents the futural direction for non-food renewable feedstocks was discussed.
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Affiliation(s)
- Bin Zhang
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang, China
| | - Yan Jiang
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang, China
| | - Zhimin Li
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang, China
| | - Fei Wang
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang, China
| | - Xiao-Yu Wu
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang, China
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32
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Hong Y, Arbter P, Wang W, Rojas LN, Zeng AP. Introduction of glycine synthase enables uptake of exogenous formate and strongly impacts the metabolism in Clostridium pasteurianum. Biotechnol Bioeng 2020; 118:1366-1380. [PMID: 33331660 DOI: 10.1002/bit.27658] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 11/11/2022]
Abstract
Autotrophic or mixotrophic use of one-carbon (C1) compounds is gaining importance for sustainable bioproduction. In an effort to integrate the reductive glycine pathway (rGP) as a highly promising pathway for the assimilation of CO2 and formate, genes coding for glycine synthase system from Gottschalkia acidurici were successfully introduced into Clostridium pasteurianum, a non-model host microorganism with industrial interests. The mutant harboring glycine synthase exhibited assimilation of exogenous formate and reduced CO2 formation. Further metabolic data clearly showed large impacts of expression of glycine synthase on the product metabolism of C. pasteurianum. In particular, 2-oxobutyrate (2-OB) was observed for the first time as a metabolic intermediate of C. pasteurianum and its secretion was solely triggered by the expression of glycine synthase. The perturbation of C1 metabolism is discussed regarding its interactions with pathways of the central metabolism, acidogenesis, solventogenesis, and amino acid metabolism. The secretion of 2-OB is considered as a consequence of metabolic and redox instabilities due to the activity of glycine synthase and may represent a common metabolic response of Clostridia in enhanced use of C1 compounds.
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Affiliation(s)
- Yaeseong Hong
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Philipp Arbter
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Wei Wang
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - Lilian N Rojas
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
| | - An-Ping Zeng
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany.,Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
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33
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Keller P, Noor E, Meyer F, Reiter MA, Anastassov S, Kiefer P, Vorholt JA. Methanol-dependent Escherichia coli strains with a complete ribulose monophosphate cycle. Nat Commun 2020; 11:5403. [PMID: 33106470 PMCID: PMC7588473 DOI: 10.1038/s41467-020-19235-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022] Open
Abstract
Methanol is a biotechnologically promising substitute for food and feed substrates since it can be produced renewably from electricity, water and CO2. Although progress has been made towards establishing Escherichia coli as a platform organism for methanol conversion via the energy efficient ribulose monophosphate (RuMP) cycle, engineering strains that rely solely on methanol as a carbon source remains challenging. Here, we apply flux balance analysis to comprehensively identify methanol-dependent strains with high potential for adaptive laboratory evolution. We further investigate two out of 1200 candidate strains, one with a deletion of fructose-1,6-bisphosphatase (fbp) and another with triosephosphate isomerase (tpiA) deleted. In contrast to previous reported methanol-dependent strains, both feature a complete RuMP cycle and incorporate methanol to a high degree, with up to 31 and 99% fractional incorporation into RuMP cycle metabolites. These strains represent ideal starting points for evolution towards a fully methylotrophic lifestyle.
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Affiliation(s)
- Philipp Keller
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Elad Noor
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Fabian Meyer
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Michael A Reiter
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Stanislav Anastassov
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Patrick Kiefer
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Julia A Vorholt
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland.
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34
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Kyle Bennett R, Agee A, Har JRG, von Hagel B, Antoniewicz MR, Papoutsakis ET. Regulatory interventions improve the biosynthesis of limiting amino acids from methanol carbon to improve synthetic methylotrophy in Escherichia coli. Biotechnol Bioeng 2020; 118:43-57. [PMID: 32876943 DOI: 10.1002/bit.27549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/29/2020] [Accepted: 08/26/2020] [Indexed: 12/30/2022]
Abstract
Synthetic methylotrophy aims to engineer methane and methanol utilization pathways in platform hosts like Escherichia coli for industrial bioprocessing of natural gas and biogas. While recent attempts to engineer synthetic methylotrophs have proved successful, autonomous methylotrophy, that is, the ability to utilize methane or methanol as sole carbon and energy substrates, has not yet been realized. Here, we address an important limitation of autonomous methylotrophy in E. coli: the inability of the organism to synthesize several amino acids when grown on methanol. We targeted global and local amino acid regulatory networks. Those include removal of amino acid allosteric feedback inhibition (argAH15Y , ilvAL447F , hisGE271K , leuAG462D , proBD107N , thrAS345F , trpES40F ), knockouts of transcriptional repressors (ihfA, metJ); and overexpression of amino acid biosynthetic operons (hisGDCBHAFI, leuABCD, thrABC, trpEDCBA) and transcriptional regulators (crp, purR). Compared to the parent methylotrophic E. coli strain that was unable to synthesize these amino acids from methanol carbon, these strategies resulted in improved biosynthesis of limiting proteinogenic amino acids (histidine, leucine, lysine, methionine, phenylalanine, threonine, tyrosine) from methanol carbon. In several cases, improved amino acid biosynthesis from methanol carbon led to improvements in methylotrophic growth in methanol minimal medium supplemented with a small amount of yeast extract. This study addresses a key limitation currently preventing autonomous methylotrophy in E. coli and possibly other synthetic methylotrophs and provides insight as to how this limitation can be alleviated via global and local regulatory modifications.
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Affiliation(s)
- Robert Kyle Bennett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Alec Agee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Jie R G Har
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Bryan von Hagel
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
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35
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Wenk S, Schann K, He H, Rainaldi V, Kim S, Lindner SN, Bar-Even A. An "energy-auxotroph" Escherichia coli provides an in vivo platform for assessing NADH regeneration systems. Biotechnol Bioeng 2020; 117:3422-3434. [PMID: 32658302 DOI: 10.1002/bit.27490] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/01/2020] [Accepted: 07/09/2020] [Indexed: 12/18/2022]
Abstract
An efficient in vivo regeneration of the primary cellular resources NADH and ATP is vital for optimizing the production of value-added chemicals and enabling the activity of synthetic pathways. Currently, such regeneration routes are tested and characterized mainly in vitro before being introduced into the cell. However, in vitro measurements could be misleading as they do not reflect enzyme activity under physiological conditions. Here, we construct an in vivo platform to test and compare NADH regeneration systems. By deleting dihydrolipoyl dehydrogenase in Escherichia coli, we abolish the activity of pyruvate dehydrogenase and 2-ketoglutarate dehydrogenase. When cultivated on acetate, the resulting strain is auxotrophic to NADH and ATP: acetate can be assimilated via the glyoxylate shunt but cannot be oxidized to provide the cell with reducing power and energy. This strain can, therefore, serve to select for and test different NADH regeneration routes. We exemplify this by comparing several NAD-dependent formate dehydrogenases and methanol dehydrogenases. We identify the most efficient enzyme variants under in vivo conditions and pinpoint optimal feedstock concentrations that maximize NADH biosynthesis while avoiding cellular toxicity. Our strain thus provides a useful platform for comparing and optimizing enzymatic systems for cofactor regeneration under physiological conditions.
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Affiliation(s)
- Sebastian Wenk
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Karin Schann
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Hai He
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Vittorio Rainaldi
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Seohyoung Kim
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Steffen N Lindner
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Arren Bar-Even
- Systems and Synthetic Metabolism Lab, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
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36
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Tuyishime P, Sinumvayo JP. Novel outlook in engineering synthetic methylotrophs and formatotrophs: a course for advancing C1-based chemicals production. World J Microbiol Biotechnol 2020; 36:118. [DOI: 10.1007/s11274-020-02899-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/13/2020] [Indexed: 12/13/2022]
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37
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Wang Y, Fan L, Tuyishime P, Liu J, Zhang K, Gao N, Zhang Z, Ni X, Feng J, Yuan Q, Ma H, Zheng P, Sun J, Ma Y. Adaptive laboratory evolution enhances methanol tolerance and conversion in engineered Corynebacterium glutamicum. Commun Biol 2020; 3:217. [PMID: 32382107 PMCID: PMC7205612 DOI: 10.1038/s42003-020-0954-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 04/03/2020] [Indexed: 12/26/2022] Open
Abstract
Synthetic methylotrophy has recently been intensively studied to achieve methanol-based biomanufacturing of fuels and chemicals. However, attempts to engineer platform microorganisms to utilize methanol mainly focus on enzyme and pathway engineering. Herein, we enhanced methanol bioconversion of synthetic methylotrophs by improving cellular tolerance to methanol. A previously engineered methanol-dependent Corynebacterium glutamicum is subjected to adaptive laboratory evolution with elevated methanol content. Unexpectedly, the evolved strain not only tolerates higher concentrations of methanol but also shows improved growth and methanol utilization. Transcriptome analysis suggests increased methanol concentrations rebalance methylotrophic metabolism by down-regulating glycolysis and up-regulating amino acid biosynthesis, oxidative phosphorylation, ribosome biosynthesis, and parts of TCA cycle. Mutations in the O-acetyl-l-homoserine sulfhydrylase Cgl0653 catalyzing formation of l-methionine analog from methanol and methanol-induced membrane-bound transporter Cgl0833 are proven crucial for methanol tolerance. This study demonstrates the importance of tolerance engineering in developing superior synthetic methylotrophs. Wang et al. improve the methanol tolerance for the synthetic methylotroph, Corynebacterium glutamicum. They generate 3 new strains by directed evolution and use biochemical, transcriptomic, and genetic approaches to characterize the pathways underlying the enhanced methanol metabolism. Their findings are important for biomanufacturing purposes.
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Affiliation(s)
- Yu Wang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Liwen Fan
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Philibert Tuyishime
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Jiao Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Kun Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ning Gao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhihui Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaomeng Ni
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Jinhui Feng
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Qianqian Yuan
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Hongwu Ma
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Ping Zheng
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. .,School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Jibin Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Yanhe Ma
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
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38
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Triggering the stringent response enhances synthetic methanol utilization in Escherichia coli. Metab Eng 2020; 61:1-10. [PMID: 32360074 DOI: 10.1016/j.ymben.2020.04.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 04/06/2020] [Accepted: 04/16/2020] [Indexed: 02/06/2023]
Abstract
Synthetic methylotrophy aims to engineer methane and methanol utilization pathways in platform hosts like Escherichia coli for industrial bioprocessing of natural gas and biogas. While recent attempts to engineer synthetic methylotrophs have proved successful, autonomous methylotrophy, i.e. the ability to utilize methane or methanol as sole carbon and energy substrates, has not yet been realized. Here, we address an important limitation of autonomous methylotrophy in E. coli: the inability of the organism to synthesize several amino acids when grown on methanol. By activating the stringent/stress response via ppGpp overproduction, or DksA and RpoS overexpression, we demonstrate improved biosynthesis of proteinogenic amino acids via endogenous upregulation of amino acid synthesis pathway genes. Thus, we were able to achieve biosynthesis of several limiting amino acids from methanol-derived carbon, in contrast to the control methylotrophic E. coli strain. This study addresses a key limitation currently preventing autonomous methylotrophy in E. coli and possibly other synthetic methylotrophs and provides insight as to how this limitation can be alleviated via stringent/stress response activation.
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39
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Bennett RK, Dillon M, Gerald Har JR, Agee A, von Hagel B, Rohlhill J, Antoniewicz MR, Papoutsakis ET. Engineering Escherichia coli for methanol-dependent growth on glucose for metabolite production. Metab Eng 2020; 60:45-55. [PMID: 32179162 DOI: 10.1016/j.ymben.2020.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/25/2020] [Accepted: 03/08/2020] [Indexed: 02/05/2023]
Abstract
Synthetic methylotrophy aims to engineer methane and methanol utilization pathways in platform hosts like Escherichia coli for industrial bioprocessing of natural gas and biogas. While recent attempts to engineer synthetic methanol auxotrophs have proved successful, these studies focused on scarce and expensive co-substrates. Here, we engineered E. coli for methanol-dependent growth on glucose, an abundant and inexpensive co-substrate, via deletion of glucose 6-phosphate isomerase (pgi), phosphogluconate dehydratase (edd), and ribose 5-phosphate isomerases (rpiAB). Since the parental strain did not exhibit methanol-dependent growth on glucose in minimal medium, we first achieved methanol-dependent growth via amino acid supplementation and used this medium to evolve the strain for methanol-dependent growth in glucose minimal medium. The evolved strain exhibited a maximum growth rate of 0.15 h-1 in glucose minimal medium with methanol, which is comparable to that of other synthetic methanol auxotrophs. Whole genome sequencing and 13C-metabolic flux analysis revealed the causative mutations in the evolved strain. A mutation in the phosphotransferase system enzyme I gene (ptsI) resulted in a reduced glucose uptake rate to maintain a one-to-one molar ratio of substrate utilization. Deletion of the e14 prophage DNA region resulted in two non-synonymous mutations in the isocitrate dehydrogenase (icd) gene, which reduced TCA cycle carbon flux to maintain the internal redox state. In high cell density glucose fed-batch fermentation, methanol-dependent acetone production resulted in 22% average carbon labeling of acetone from 13C-methanol, which far surpasses that of the previous best (2.4%) found with methylotrophic E. coli Δpgi. This study addresses the need to identify appropriate co-substrates for engineering synthetic methanol auxotrophs and provides a basis for the next steps toward industrial one-carbon bioprocessing.
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Affiliation(s)
- R Kyle Bennett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - Michael Dillon
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - Jie Ren Gerald Har
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA.
| | - Alec Agee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - Bryan von Hagel
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - Julia Rohlhill
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA.
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
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Rohlhill J, Gerald Har JR, Antoniewicz MR, Papoutsakis ET. Improving synthetic methylotrophy via dynamic formaldehyde regulation of pentose phosphate pathway genes and redox perturbation. Metab Eng 2019; 57:247-255. [PMID: 31881281 DOI: 10.1016/j.ymben.2019.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/17/2019] [Accepted: 12/21/2019] [Indexed: 12/25/2022]
Abstract
Escherichia coli is an ideal choice for constructing synthetic methylotrophs capable of utilizing the non-native substrate methanol as a carbon and energy source. All current E. coli-based synthetic methylotrophs require co-substrates. They display variable levels of methanol-carbon incorporation due to a lack of native regulatory control of biosynthetic pathways, as E. coli does not recognize methanol as a proper substrate despite its ability to catabolize it. Here, using the E. coli formaldehyde-inducible promoter Pfrm, we implement dynamic expression control of select pentose-phosphate genes in response to the formaldehyde produced upon methanol oxidation. Genes under Pfrm control exhibited 8- to 30-fold transcriptional upregulation during growth on methanol. Formaldehyde-induced episomal expression of the B. methanolicus rpe and tkt genes involved in the regeneration of ribulose 5-phosphate required for formaldehyde fixation led to significantly improved methanol assimilation into intracellular metabolites, including a 2-fold increase of 13C-methanol into glutamate. Using a simple strategy for redox perturbation by deleting the E. coli NAD-dependent malate dehydrogenase gene maldh, we demonstrate 5-fold improved biomass formation of cells growing on methanol in the presence of a small concentration of yeast extract. Further improvements in methanol utilization are achieved via adaptive laboratory evolution and heterologous rpe and tkt expression. A short-term in vivo13C-methanol labeling assay was used to determine methanol assimilation activity for Δmaldh strains, and demonstrated dramatically higher labeling in intracellular metabolites, including a 6-fold and 1.8-fold increase in glycine labeling for the rpe/tkt and evolved strains, respectively. The combination of formaldehyde-controlled pentose phosphate pathway expression and redox perturbation with the maldh knock-out greatly improved both growth benefit with methanol and methanol carbon incorporation into intracellular metabolites.
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Affiliation(s)
- Julia Rohlhill
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA; Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, DE, 19711, USA
| | - Jie Ren Gerald Har
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA; Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, DE, 19711, USA.
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