1
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Willers VP, Beer B, Sieber V. Integrating Carbohydrate and C1 Utilization for Chemicals Production. CHEMSUSCHEM 2023; 16:e202202122. [PMID: 36520644 DOI: 10.1002/cssc.202202122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/14/2022] [Indexed: 06/17/2023]
Abstract
In the face of increasing mobility and energy demand, as well as the mitigation of climate change, the development of sustainable and environmentally friendly alternatives to fossil fuels will be one of the most important tasks facing humankind in the coming years. In order to initiate the transition from a petroleum-based economy to a new, greener future, biofuels and synthetic fuels have great potential as they can be adapted to already common processes. Thereby, especially synthetic fuels from CO2 and renewable energies are seen as the next big step for a sustainable and ecological life. In our study, we directly address the sustainable production of the most common biofuel, ethanol, and the highly interesting next-generation biofuel, isobutanol, from methanol and xylose, which are directly derivable from CO2 and lignocellulosic waste streams, respectively, such integrating synthetic fuel and biofuel production. After enzyme and reaction optimization, we succeeded in producing either 3 g L-1 ethanol or 2 g L-1 isobutanol from 7.5 g L-1 xylose and 1.6 g L-1 methanol. In our cell-free enzyme system, C1-compounds are efficiently combined and fixed by the key enzyme transketolase and converted to the intermediate pyruvate. This opens the way for a hybrid production of biofuels, platform chemicals and fine chemicals from CO2 and lignocellulosic waste streams as alternative to conventional routes depending solely either on CO2 or sugars.
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Affiliation(s)
- Vivian Pascal Willers
- Chair of Chemistry of Biogenic Resources, Technical University of Munich Campus Straubing, 94315, Straubing, Germany
| | - Barbara Beer
- Chair of Chemistry of Biogenic Resources, Technical University of Munich Campus Straubing, 94315, Straubing, Germany
- Current address: CASCAT GmbH, 94315, Straubing, Germany
| | - Volker Sieber
- Chair of Chemistry of Biogenic Resources, Technical University of Munich Campus Straubing, 94315, Straubing, Germany
- Technical University of Munich, 94315, Straubing, Germany
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia
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2
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Wagner N, Bade F, Straube E, Rabe K, Frazão CJR, Walther T. In vivo implementation of a synthetic metabolic pathway for the carbon-conserving conversion of glycolaldehyde to acetyl-CoA. Front Bioeng Biotechnol 2023; 11:1125544. [PMID: 36845174 PMCID: PMC9947464 DOI: 10.3389/fbioe.2023.1125544] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Ethylene glycol (EG) derived from plastic waste or CO2 can serve as a substrate for microbial production of value-added chemicals. Assimilation of EG proceeds though the characteristic intermediate glycolaldehyde (GA). However, natural metabolic pathways for GA assimilation have low carbon efficiency when producing the metabolic precursor acetyl-CoA. In alternative, the reaction sequence catalyzed by EG dehydrogenase, d-arabinose 5-phosphate aldolase, d-arabinose 5-phosphate isomerase, d-ribulose 5-phosphate 3-epimerase (Rpe), d-xylulose 5-phosphate phosphoketolase, and phosphate acetyltransferase may enable the conversion of EG into acetyl-CoA without carbon loss. We investigated the metabolic requirements for in vivo function of this pathway in Escherichia coli by (over)expressing constituting enzymes in different combinations. Using 13C-tracer experiments, we first examined the conversion of EG to acetate via the synthetic reaction sequence and showed that, in addition to heterologous phosphoketolase, overexpression of all native enzymes except Rpe was required for the pathway to function. Since acetyl-CoA could not be reliably quantified by our LC/MS-method, the distribution of isotopologues in mevalonate, a stable metabolite that is exclusively derived from this intermediate, was used to probe the contribution of the synthetic pathway to biosynthesis of acetyl-CoA. We detected strong incorporation of 13C carbon derived from labeled GA in all intermediates of the synthetic pathway. In presence of unlabeled co-substrate glycerol, 12.4% of the mevalonate (and therefore acetyl-CoA) was derived from GA. The contribution of the synthetic pathway to acetyl-CoA production was further increased to 16.1% by the additional expression of the native phosphate acyltransferase enzyme. Finally, we demonstrated that conversion of EG to mevalonate was feasible albeit at currently extremely small yields.
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Affiliation(s)
- Nils Wagner
- TU Dresden, Institute of Natural Materials Technology, Dresden, Germany
| | - Frederik Bade
- TU Dresden, Institute of Natural Materials Technology, Dresden, Germany
| | - Elly Straube
- TU Dresden, Institute of Natural Materials Technology, Dresden, Germany
| | - Kenny Rabe
- TU Dresden, Institute of Natural Materials Technology, Dresden, Germany
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3
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Yang P, Liu W, Chen Y, Gong AD. Engineering the glyoxylate cycle for chemical bioproduction. Front Bioeng Biotechnol 2022; 10:1066651. [PMID: 36532595 PMCID: PMC9755347 DOI: 10.3389/fbioe.2022.1066651] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/17/2022] [Indexed: 07/24/2023] Open
Abstract
With growing concerns about environmental issues and sustainable economy, bioproduction of chemicals utilizing microbial cell factories provides an eco-friendly alternative to current petro-based processes. Creating high-performance strains (with high titer, yield, and productivity) through metabolic engineering strategies is critical for cost-competitive production. Commonly, it is inevitable to fine-tuning or rewire the endogenous or heterologous pathways in such processes. As an important pathway involved in the synthesis of many kinds of chemicals, the potential of the glyoxylate cycle in metabolic engineering has been studied extensively these years. Here, we review the metabolic regulation of the glyoxylate cycle and summarize recent achievements in microbial production of chemicals through tuning of the glyoxylate cycle, with a focus on studies implemented in model microorganisms. Also, future prospects for bioproduction of glyoxylate cycle-related chemicals are discussed.
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4
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Tan B, Zheng Y, Yan H, Liu Y, Li ZJ. Metabolic engineering of Halomonas bluephagenesis to metabolize xylose for poly-3-hydroxybutyrate production. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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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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6
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Kovács SC, Szappanos B, Tengölics R, Notebaart RA, Papp B. Underground metabolism as a rich reservoir for pathway engineering. Bioinformatics 2022; 38:3070-3077. [PMID: 35441658 PMCID: PMC9154287 DOI: 10.1093/bioinformatics/btac282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022] Open
Abstract
Motivation Bioproduction of value-added compounds is frequently achieved by utilizing enzymes from other species. However, expression of such heterologous enzymes can be detrimental due to unexpected interactions within the host cell. Recently, an alternative strategy emerged, which relies on recruiting side activities of host enzymes to establish new biosynthetic pathways. Although such low-level ‘underground’ enzyme activities are prevalent, it remains poorly explored whether they may serve as an important reservoir for pathway engineering. Results Here, we use genome-scale modeling to estimate the theoretical potential of underground reactions for engineering novel biosynthetic pathways in Escherichia coli. We found that biochemical reactions contributed by underground enzyme activities often enhance the in silico production of compounds with industrial importance, including several cases where underground activities are indispensable for production. Most of these new capabilities can be achieved by the addition of one or two underground reactions to the native network, suggesting that only a few side activities need to be enhanced during implementation. Remarkably, we find that the contribution of underground reactions to the production of value-added compounds is comparable to that of heterologous reactions, underscoring their biotechnological potential. Taken together, our genome-wide study demonstrates that exploiting underground enzyme activities could be a promising addition to the toolbox of industrial strain development. Availability and implementation The data and scripts underlying this article are available on GitHub at https://github.com/pappb/Kovacs-et-al-Underground-metabolism. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Szabolcs Cselgő Kovács
- HCEMM-BRC Metabolic Systems Biology Lab, Szeged, Hungary.,Biological Research Centre, Institute of Biochemistry, Synthetic and Systems Biology Unit, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Balázs Szappanos
- HCEMM-BRC Metabolic Systems Biology Lab, Szeged, Hungary.,Biological Research Centre, Institute of Biochemistry, Synthetic and Systems Biology Unit, Eötvös Loránd Research Network (ELKH), Szeged, Hungary.,Department of Biotechnology, University of Szeged, Szeged, Hungary
| | - Roland Tengölics
- HCEMM-BRC Metabolic Systems Biology Lab, Szeged, Hungary.,Biological Research Centre, Institute of Biochemistry, Synthetic and Systems Biology Unit, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Richard A Notebaart
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Balázs Papp
- HCEMM-BRC Metabolic Systems Biology Lab, Szeged, Hungary.,Biological Research Centre, Institute of Biochemistry, Synthetic and Systems Biology Unit, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
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7
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Shi LL, Zheng Y, Tan BW, Li ZJ. Establishment of a carbon-efficient xylulose cleavage pathway in Escherichia coli to metabolize xylose. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Heo JM, Kim HJ, Lee SJ. Efficient anaerobic consumption of D-xylose by E. coli BL21(DE3) via xylR adaptive mutation. BMC Microbiol 2021; 21:332. [PMID: 34872501 PMCID: PMC8647362 DOI: 10.1186/s12866-021-02395-9] [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: 03/30/2021] [Accepted: 11/22/2021] [Indexed: 11/20/2022] Open
Abstract
Background Microorganisms can prioritize the uptake of different sugars depending on their metabolic needs and preferences. When both D-glucose and D-xylose are present in growth media, E. coli cells typically consume D-glucose first and then D-xylose. Similarly, when E. coli BL21(DE3) is provided with both D-glucose and D-xylose under anaerobic conditions, glucose is consumed first, whereas D-xylose is consumed very slowly. Results When BL21(DE3) was adaptively evolved via subculture, the consumption rate of D-xylose increased gradually. Strains JH001 and JH019, whose D-xylose consumption rate was faster, were isolated after subculture. Genome analysis of the JH001 and JH019 strains revealed that C91A (Q31K) and C740T (A247V) missense mutations in the xylR gene (which encodes the XylR transcriptional activator), respectively, controlled the expression of the xyl operon. RT-qPCR analyses demonstrated that the XylR mutation caused a 10.9-fold and 3.5-fold increase in the expression of the xylA (xylose isomerase) and xylF (xylose transporter) genes, respectively, in the adaptively evolved JH001 and JH019 strains. A C91A adaptive mutation was introduced into a new BL21(DE3) background via single-base genome editing, resulting in immediate and efficient D-xylose consumption. Conclusions Anaerobically-adapted BL21(DE3) cells were obtained through short-term adaptive evolution and xylR mutations responsible for faster D-xylose consumption were identified, which may aid in the improvement of microbial fermentation technology. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02395-9.
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Affiliation(s)
- Jung Min Heo
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Hyun Ju Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Sang Jun Lee
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea.
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9
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Griffith CM, Walvekar AS, Linster CL. Approaches for completing metabolic networks through metabolite damage and repair discovery. CURRENT OPINION IN SYSTEMS BIOLOGY 2021; 28:None. [PMID: 34957344 PMCID: PMC8669784 DOI: 10.1016/j.coisb.2021.100379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Metabolites are prone to damage, either via enzymatic side reactions, which collectively form the underground metabolism, or via spontaneous chemical reactions. The resulting non-canonical metabolites that can be toxic, are mended by dedicated "metabolite repair enzymes." Deficiencies in the latter can cause severe disease in humans, whereas inclusion of repair enzymes in metabolically engineered systems can improve the production yield of value-added chemicals. The metabolite damage and repair loops are typically not yet included in metabolic reconstructions and it is likely that many remain to be discovered. Here, we review strategies and associated challenges for unveiling non-canonical metabolites and metabolite repair enzymes, including systematic approaches based on high-resolution mass spectrometry, metabolome-wide side-activity prediction, as well as high-throughput substrate and phenotypic screens.
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Affiliation(s)
| | | | - Carole L. Linster
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
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10
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Understanding D-xylonic acid accumulation: a cornerstone for better metabolic engineering approaches. Appl Microbiol Biotechnol 2021; 105:5309-5324. [PMID: 34215905 DOI: 10.1007/s00253-021-11410-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 01/02/2023]
Abstract
The xylose oxidative pathway (XOP) has been engineered in microorganisms for the production of a wide range of industrially relevant compounds. However, the performance of metabolically engineered XOP-utilizing microorganisms is typically hindered by D-xylonic acid accumulation. It acidifies the media and perturbs cell growth due to toxicity, thus curtailing enzymatic activity and target product formation. Fortunately, from the growing portfolio of genetic tools, several strategies that can be adapted for the generation of efficient microbial cell factories have been implemented to address D-xylonic acid accumulation. This review centers its discussion on the causes of D-xylonic acid accumulation and how to address it through different engineering and synthetic biology techniques with emphasis given on bacterial strains. In the first part of this review, the ability of certain microorganisms to produce and tolerate D-xylonic acid is also tackled as an important aspect in developing efficient microbial cell factories. Overall, this review could shed some insights and clarity to those working on XOP in bacteria and its engineering for the development of industrially applicable product-specialist strains. KEY POINTS: D-Xylonic acid accumulation is attributed to the overexpression of xylose dehydrogenase concomitant with basal or inefficient expression of enzymes involved in D-xylonic acid assimilation. Redox imbalance and insufficient cofactors contribute to D-xylonic acid accumulation. Overcoming D-xylonic acid accumulation can increase product formation among engineered strains. Engineering strategies involving enzyme engineering, evolutionary engineering, coutilization of different sugar substrates, and synergy of different pathways could potentially address D-xylonic acid accumulation.
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11
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Bañares AB, Nisola GM, Valdehuesa KNG, Lee WK, Chung WJ. Engineering of xylose metabolism in Escherichia coli for the production of valuable compounds. Crit Rev Biotechnol 2021; 41:649-668. [PMID: 33563072 DOI: 10.1080/07388551.2021.1873243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The lignocellulosic sugar d-xylose has recently gained prominence as an inexpensive alternative substrate for the production of value-added compounds using genetically modified organisms. Among the prokaryotes, Escherichia coli has become the de facto host for the development of engineered microbial cell factories. The favored status of E. coli resulted from a century of scientific explorations leading to a deep understanding of its systems. However, there are limited literature reviews that discuss engineered E. coli as a platform for the conversion of d-xylose to any target compounds. Additionally, available critical review articles tend to focus on products rather than the host itself. This review aims to provide relevant and current information about significant advances in the metabolic engineering of d-xylose metabolism in E. coli. This focusses on unconventional and synthetic d-xylose metabolic pathways as several review articles have already discussed the engineering of native d-xylose metabolism. This paper, in particular, is essential to those who are working on engineering of d-xylose metabolism using E. coli as the host.
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Affiliation(s)
- Angelo B Bañares
- Environmental Waste Recycle Institute (EWRI), Department of Energy Science and Technology (DEST), Myongji University, Yongin, Gyeonggi, South Korea
| | - Grace M Nisola
- Environmental Waste Recycle Institute (EWRI), Department of Energy Science and Technology (DEST), Myongji University, Yongin, Gyeonggi, South Korea
| | - Kris N G Valdehuesa
- Environmental Waste Recycle Institute (EWRI), Department of Energy Science and Technology (DEST), Myongji University, Yongin, Gyeonggi, South Korea
| | - Won-Keun Lee
- Division of Bioscience and Bioinformatics, Myongji University, Yongin, Gyeonggi, South Korea
| | - Wook-Jin Chung
- Environmental Waste Recycle Institute (EWRI), Department of Energy Science and Technology (DEST), Myongji University, Yongin, Gyeonggi, South Korea
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Abstract
Glycerol is a readily available and inexpensive substance that is mostly generated during biofuel production processes. In order to ensure the viability of the biofuel industry, it is essential to develop complementing technologies for the resource utilization of glycerol. Ethylene glycol is a two-carbon organic chemical with multiple applications and a huge market. In this study, an artificial enzymatic cascade comprised alditol oxidase, catalase, glyoxylate/hydroxypyruvate reductase, pyruvate decarboxylase and lactaldehyde:propanediol oxidoreductase was developed for the production of ethylene glycol from glycerol. The reduced nicotinamide adenine dinucleotide (NADH) generated during the dehydrogenation of the glycerol oxidation product d-glycerate can be as the reductant to support the ethylene glycol production. Using this in vitro synthetic system with self-sufficient NADH recycling, 7.64 ± 0.15 mM ethylene glycol was produced from 10 mM glycerol in 10 h, with a high yield of 0.515 ± 0.1 g/g. The in vitro enzymatic cascade is not only a promising alternative for the generation of ethylene glycol but also a successful example of the value-added utilization of glycerol.
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13
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Enhanced glycolic acid yield through xylose and cellobiose utilization by metabolically engineered Escherichia coli. Bioprocess Biosyst Eng 2021; 44:1081-1091. [PMID: 33527231 DOI: 10.1007/s00449-020-02502-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/24/2020] [Indexed: 12/11/2022]
Abstract
Microbial biorefinery is a promising route toward sustainable production of glycolic acid (GA), a valuable raw material for various industries. However, inherent microbial GA production has limited substrate consumption using either D-xylose or D-glucose as carbon catabolite repression (CCR) averts their co-utilization. To bypass CCR, a GA-producing strain using D-xylose via Dahms pathway was engineered to allow cellobiose uptake. Unlike glucose, cellobiose was assimilated and intracellularly degraded without repressing D-xylose uptake. The final GA-producing E. coli strain (CLGA8) has an overexpressed cellobiose phosphorylase (cep94A) from Saccharophagus degradans 2-40 and an activated glyoxylate shunt pathway. Expression of cep94A improved GA production reaching the maximum theoretical yield (0.51 g GA g-1 xylose), whereas activation of glyoxylate shunt pathway enabled GA production from cellobiose, which further increased the GA titer (2.25 g GA L-1). To date, this is the highest reported GA yield from D-xylose through Dahms pathway in an engineered E. coli with cellobiose as co-substrate.
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14
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Pandit AV, Harrison E, Mahadevan R. Engineering Escherichia coli for the utilization of ethylene glycol. Microb Cell Fact 2021; 20:22. [PMID: 33482812 PMCID: PMC7821661 DOI: 10.1186/s12934-021-01509-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/02/2021] [Indexed: 01/29/2023] Open
Abstract
Background A considerable challenge in the development of bioprocesses for producing chemicals and fuels has been the high cost of feedstocks relative to oil prices, making it difficult for these processes to compete with their conventional petrochemical counterparts. Hence, in the absence of high oil prices in the near future, there has been a shift in the industry to produce higher value compounds such as fragrances for cosmetics. Yet, there is still a need to address climate change and develop biotechnological approaches for producing large market, lower value chemicals and fuels. Results In this work, we study ethylene glycol (EG), a novel feedstock that we believe has promise to address this challenge. We engineer Escherichia coli (E. coli) to consume EG and examine glycolate production as a case study for chemical production. Using a combination of modeling and experimental studies, we identify oxygen concentration as an important metabolic valve in the assimilation and use of EG as a substrate. Two oxygen-based strategies are thus developed and tested in fed-batch bioreactors. Ultimately, the best glycolate production strategy employed a target respiratory quotient leading to the highest observed fermentation performance. With this strategy, a glycolate titer of 10.4 g/L was reached after 112 h of production time in a fed-batch bioreactor. Correspondingly, a yield of 0.8 g/g from EG and productivity of 0.1 g/L h were measured during the production stage. Our modeling and experimental results clearly suggest that oxygen concentration is an important factor in the assimilation and use of EG as a substrate. Finally, our use of metabolic modeling also sheds light on the intracellular distribution through central metabolism, implicating flux to 2-phosphoglycerate as the primary route for EG assimilation. Conclusion Overall, our work suggests that EG could provide a renewable starting material for commercial biosynthesis of fuels and chemicals that may achieve economic parity with petrochemical feedstocks while sequestering carbon dioxide.
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Affiliation(s)
- Aditya Vikram Pandit
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Emma Harrison
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada. .,Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, M5S 3G9, Canada.
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15
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Li Y, Yang S, Ma D, Song W, Gao C, Liu L, Chen X. Microbial engineering for the production of C 2-C 6 organic acids. Nat Prod Rep 2021; 38:1518-1546. [PMID: 33410446 DOI: 10.1039/d0np00062k] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Covering: up to the end of 2020Organic acids, as building block compounds, have been widely used in food, pharmaceutical, plastic, and chemical industries. Until now, chemical synthesis is still the primary method for industrial-scale organic acid production. However, this process encounters some inevitable challenges, such as depletable petroleum resources, harsh reaction conditions and complex downstream processes. To solve these problems, microbial cell factories provide a promising approach for achieving the sustainable production of organic acids. However, some key metabolites in central carbon metabolism are strictly regulated by the network of cellular metabolism, resulting in the low productivity of organic acids. Thus, multiple metabolic engineering strategies have been developed to reprogram microbial cell factories to produce organic acids, including monocarboxylic acids, hydroxy carboxylic acids, amino carboxylic acids, dicarboxylic acids and monomeric units for polymers. These strategies mainly center on improving the catalytic efficiency of the enzymes to increase the conversion rate, balancing the multi-gene biosynthetic pathways to reduce the byproduct formation, strengthening the metabolic flux to promote the product biosynthesis, optimizing the metabolic network to adapt the environmental conditions and enhancing substrate utilization to broaden the substrate spectrum. Here, we describe the recent advances in producing C2-C6 organic acids by metabolic engineering strategies. In addition, we provide new insights as to when, what and how these strategies should be taken. Future challenges are also discussed in further advancing microbial engineering and establishing efficient biorefineries.
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Affiliation(s)
- Yang Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
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16
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Carr CM, Clarke DJ, Dobson ADW. Microbial Polyethylene Terephthalate Hydrolases: Current and Future Perspectives. Front Microbiol 2020; 11:571265. [PMID: 33262744 PMCID: PMC7686037 DOI: 10.3389/fmicb.2020.571265] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022] Open
Abstract
Plastic has rapidly transformed our world, with many aspects of human life now relying on a variety of plastic materials. Biological plastic degradation, which employs microorganisms and their degradative enzymes, has emerged as one way to address the unforeseen consequences of the waste streams that have resulted from mass plastic production. The focus of this review is microbial hydrolase enzymes which have been found to act on polyethylene terephthalate (PET) plastic. The best characterized examples are discussed together with the use of genomic and protein engineering technologies to obtain PET hydrolase enzymes for different applications. In addition, the obstacles which are currently limiting the development of efficient PET bioprocessing are presented. By continuing to study the possible mechanisms and the structural elements of key enzymes involved in microbial PET hydrolysis, and by assessing the ability of PET hydrolase enzymes to work under practical conditions, this research will help inform large-scale waste management operations. Finally, the contribution of microbial PET hydrolases in creating a potential circular PET economy will be explored. This review combines the current knowledge on enzymatic PET processing with proposed strategies for optimization and use, to help clarify the next steps in addressing pollution by PET and other plastics.
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Affiliation(s)
- Clodagh M. Carr
- School of Microbiology, University College Cork, Cork, Ireland
| | - David J. Clarke
- School of Microbiology, University College Cork, Cork, Ireland
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork, Cork, Ireland
- SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland
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Zhan T, Chen Q, Zhang C, Bi C, Zhang X. Constructing a Novel Biosynthetic Pathway for the Production of Glycolate from Glycerol in Escherichia coli. ACS Synth Biol 2020; 9:2600-2609. [PMID: 32794740 DOI: 10.1021/acssynbio.0c00404] [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] [Indexed: 12/11/2022]
Abstract
Glycolate is an important α-hydroxy acid with a wide range of industrial applications. The current industrial production of glycolate mainly depends on chemical synthesis, but biochemical production from renewable resources using engineered microorganisms is increasingly viewed as an attractive alternative. Crude glycerol is an abundant byproduct of biodiesel production and a widely investigated potential sustainable feedstock. Here, we constructed a novel biosynthetic pathway for the production of glycolate from glycerol in Escherichia coli. The pathway starts from the oxidation of glycerol to d-glycerate by alditol oxidase, followed by sequential enzymatic dehydrogenation and decarboxylation as well as reduction reactions. We screened and characterized the catalytic activity of candidate enzymes, and a variant of alditol oxidase from Streptomyces coelicolor A3(2), 2-hydroxyglutarate-pyruvate transhydrogenase from Saccharomyces cerevisiae, α-ketoisovalerate decarboxylase from Lactococcus lactis, and aldehyde dehydrogenase from Escherichia coli were selected and assembled to create an artificial operon for the biosynthetic production of glycolate from glycerol. We also characterized the native strong constitutive promoter Plpp from E. coli and compared it with the PT7 promoter, which was employed to express the artificial operon on the plasmid pSC105-ADKA. To redirect glycerol flux toward glycolate synthesis, we deleted key genes of the native glycerol assimilation pathways and other branches of native E. coli metabolism, and we introduced a second plasmid expressing Dld3 to reduce the accumulation of the intermediate d-glycerate. Finally, the engineered strain TZ-108 harboring pSC105-ADKA and pACYC184-Plpp-Dld3 produced 0.64 g/L glycolate in shake flasks, which was increased to 4.74 g/L in fed-batch fermentation. This study provides an alternative pathway for glycolate synthesis and demonstrates the potential for producing other commodity chemicals by redesigning glycerol metabolism.
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Affiliation(s)
- Tao Zhan
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Qian Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Chao Zhang
- College of Chemistry and Life Sciences, Changchun University of Technology, Changchun, Jilin 130012, China
| | - Changhao Bi
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Xueli Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
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18
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Zhao Z, Xian M, Liu M, Zhao G. Biochemical routes for uptake and conversion of xylose by microorganisms. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:21. [PMID: 32021652 PMCID: PMC6995148 DOI: 10.1186/s13068-020-1662-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/21/2020] [Indexed: 05/23/2023]
Abstract
Xylose is a major component of lignocellulose and the second most abundant sugar present in nature. Efficient utilization of xylose is required for the development of economically viable processes to produce biofuels and chemicals from biomass. However, there are still some bottlenecks in the bioconversion of xylose, including the fact that some microorganisms cannot assimilate xylose naturally and that the uptake and metabolism of xylose are inhibited by glucose, which is usually present with xylose in lignocellulose hydrolysate. To overcome these issues, numerous efforts have been made to discover, characterize, and engineer the transporters and enzymes involved in xylose utilization to relieve glucose inhibition and to develop recombinant microorganisms to produce fuels and chemicals from xylose. Here we describe a recent advancement focusing on xylose-utilizing pathways, biosynthesis of chemicals from xylose, and engineering strategies used to improve the conversion efficiency of xylose.
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Affiliation(s)
- Zhe Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
| | - Min Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
| | - Guang Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
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19
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Francois JM, Alkim C, Morin N. Engineering microbial pathways for production of bio-based chemicals from lignocellulosic sugars: current status and perspectives. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:118. [PMID: 32670405 PMCID: PMC7341569 DOI: 10.1186/s13068-020-01744-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/01/2020] [Indexed: 05/08/2023]
Abstract
Lignocellulose is the most abundant biomass on earth with an annual production of about 2 × 1011 tons. It is an inedible renewable carbonaceous resource that is very rich in pentose and hexose sugars. The ability of microorganisms to use lignocellulosic sugars can be exploited for the production of biofuels and chemicals, and their concurrent biotechnological processes could advantageously replace petrochemicals' processes in a medium to long term, sustaining the emerging of a new economy based on bio-based products from renewable carbon sources. One of the major issues to reach this objective is to rewire the microbial metabolism to optimally configure conversion of these lignocellulosic-derived sugars into bio-based products in a sustainable and competitive manner. Systems' metabolic engineering encompassing synthetic biology and evolutionary engineering appears to be the most promising scientific and technological approaches to meet this challenge. In this review, we examine the most recent advances and strategies to redesign natural and to implement non-natural pathways in microbial metabolic framework for the assimilation and conversion of pentose and hexose sugars derived from lignocellulosic material into industrial relevant chemical compounds leading to maximal yield, titer and productivity. These include glycolic, glutaric, mesaconic and 3,4-dihydroxybutyric acid as organic acids, monoethylene glycol, 1,4-butanediol and 1,2,4-butanetriol, as alcohols. We also discuss the big challenges that still remain to enable microbial processes to become industrially attractive and economically profitable.
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Affiliation(s)
- Jean Marie Francois
- Toulouse Biotechnology Institute, CNRS, INRA, LISBP INSA, 135 Avenue de Rangueil, Toulouse Cedex 04, 31077 France
- Toulouse White Biotechnology (TWB, UMS INRA/INSA/CNRS), NAPA CENTER Bât B, 3 Rue Ariane 31520, Ramonville Saint-Agnes, France
| | - Ceren Alkim
- Toulouse Biotechnology Institute, CNRS, INRA, LISBP INSA, 135 Avenue de Rangueil, Toulouse Cedex 04, 31077 France
- Toulouse White Biotechnology (TWB, UMS INRA/INSA/CNRS), NAPA CENTER Bât B, 3 Rue Ariane 31520, Ramonville Saint-Agnes, France
| | - Nicolas Morin
- Toulouse Biotechnology Institute, CNRS, INRA, LISBP INSA, 135 Avenue de Rangueil, Toulouse Cedex 04, 31077 France
- Toulouse White Biotechnology (TWB, UMS INRA/INSA/CNRS), NAPA CENTER Bât B, 3 Rue Ariane 31520, Ramonville Saint-Agnes, France
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20
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Lee SS, Park J, Heo YB, Woo HM. Case study of xylose conversion to glycolate in Corynebacterium glutamicum: Current limitation and future perspective of the CRISPR-Cas systems. Enzyme Microb Technol 2020; 132:109395. [PMID: 31731968 DOI: 10.1016/j.enzmictec.2019.109395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/11/2019] [Accepted: 08/05/2019] [Indexed: 11/30/2022]
Abstract
RNA-guided genome engineering technologies have been developed for the advanced metabolic engineering of microbial cells to enhance the production of value-added chemicals in Corynebacterium glutamicum as an industrial host. Here, we described the biotransformation of xylose to glycolate using engineered Corynebacterium glutamicum, a well-known industrial amino acid producer. A synthetic pathway involving heterologous D-tagatose 3-epimerase and L-fuculose kinase/aldolase reactions was introduced in C. glutamicum, resulting in 9.9 ± 0.01 g/L glycolate from 20 g/L xylose at a yield of 0.51 g/g (equal to 1.0 mol/mol). Additional glyoxylate reduction pathway developed by CRISPR-Cas12a recombineering has been introduced and attempted to increase the maximum theoretical molar yield of 2.0 (mol/mol). Due to the limitation of the CRISPR-Cas12a recombineering with TTTV PAM sites, advanced CRISPR-Cas systems were suggested for the next-round metabolic engineering for improving the glycolate yield to overcome the current genome-editing tool for metabolic engineering in C. glutamicum.
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Affiliation(s)
- Seung Soo Lee
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Jaehyun Park
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Yu Been Heo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
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21
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Lee S, Choi JI, Woo HM. Bioconversion of Xylose to Ethylene Glycol and Glycolate in Engineered Corynebacterium glutamicum. ACS OMEGA 2019; 4:21279-21287. [PMID: 31867522 PMCID: PMC6921644 DOI: 10.1021/acsomega.9b02805] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/20/2019] [Indexed: 05/05/2023]
Abstract
The biological production of two-carbon compounds (ethylene glycol (EG) and glycolate) has been studied for the sustainable supply of the compounds to the polymer, cosmetic, textile, and medical industries. Here, we demonstrated the bioconversion of xylose to either ethylene glycol (EG) or glycolate using engineered Corynebacterium glutamicum, a well-known industrial amino acid producer. A synthetic ribulose 1-phosphate (Ru1P) pathway involving heterologous d-tagatose 3-epimerase and l-fuculose kinase/aldolase reactions was introduced in C. glutamicum. Subsequently, heterologous expression of Escherichia coli YqhD reductase with the synthetic Ru1P pathway led to ethylene glycol production from xylose. Additional pathway engineering in C. glutamicum by mutating ald, which encodes an aldehyde dehydrogenase, abolished the by-product formation of glycolate during xylose conversion to EG at a yield of 0.75 mol per mol. In addition, the bioconversion of xylose to glycolate was achieved, and the almost maximum molar yield was 0.99 mol per mol xylose in C. glutamicum via the Ru1P pathway. Thus, the synthetic Ru1P pathway in C. glutamicum led bioconversion of xylose to either ethylene glycol or glycolate with high molar yields.
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Affiliation(s)
- Seung
Soo Lee
- Department
of Food Science and Biotechnology, Sungkyunkwan
University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Jong-il Choi
- Department
of Biotechnology and Bioengineering, Chonnam
National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Han Min Woo
- Department
of Food Science and Biotechnology, Sungkyunkwan
University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
- E-mail: . Tel: +82 31 290 7808. Fax: +82 31 290 7882
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22
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Lachaux C, Frazao CJR, Krauβer F, Morin N, Walther T, François JM. A New Synthetic Pathway for the Bioproduction of Glycolic Acid From Lignocellulosic Sugars Aimed at Maximal Carbon Conservation. Front Bioeng Biotechnol 2019; 7:359. [PMID: 31850327 PMCID: PMC6900487 DOI: 10.3389/fbioe.2019.00359] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 11/12/2019] [Indexed: 12/19/2022] Open
Abstract
Glycolic acid is a two-carbon α-hydroxy acid with many applications in industrial sectors including packaging, fine chemistry, cosmetics, and pharmaceutics. Currently, glycolic acid is chemically manufactured from fossil resources. This chemical mode of production is raising some concerns regarding its use in health for personal care. Microbial production of GA stands as a remarkable challenge to meet these concerns, while responding to the increasing demand to produce bio-sourced products from renewable carbon resources. We here report on the design and expression of a novel non-natural pathway of glycolic acid in E. coli. The originality of this new pathway, termed "glycoptimus" relies on two pillars. On the one hand, it requires the overexpression of three naturally occurring E. coli genes, namely kdsD encoding a D-arabinose-5-P isomerase, fsaA encoding a class 1 aldolase that cleaves D-arabinose-5-P into glyceraldehyde-3-P and glycolaldehyde, and aldA coding for an aldehyde dehydrogenase that oxidizes glycoladehyde in glycolate. These three genes constitute the "glycoptimus module." On the other hand, the expression of these genes together with a reshaping of the central carbon metabolism should enable a production of glycolic acid from pentose and hexose at a molar ratio of 2.5 and 3, respectively, which corresponds to 50% increase as compared to the existing pathways. We demonstrated the 'in vivo' potentiality of this pathway using an E. coli strain, which constitutively expressed the glycoptimus module and whose carbon flow in glycolysis was blocked at the level of glyceraldehyde-3-P dehydrogenase reaction step. This engineered strain was cultivated on a permissive medium containing malate and D-glucose. Upon exhaustion of malate, addition of either D-glucose, D-xylose or L-arabinose led to the production of glycolic acid reaching about 30% of the maximum molar yield. Further improvements at the level of enzymes, strains and bioprocess engineering are awaited to increase yield and titer, rendering the microbial production of glycolic acid affordable for a cost-effective industrial process.
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Affiliation(s)
- Cléa Lachaux
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France.,TWB, Toulouse, France
| | - Cláudio J R Frazao
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Franziska Krauβer
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Nicolas Morin
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France.,TWB, Toulouse, France
| | - Thomas Walther
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France.,TWB, Toulouse, France
| | - Jean Marie François
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France.,TWB, Toulouse, France
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23
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Promdonkoy P, Siripong W, Downes JJ, Tanapongpipat S, Runguphan W. Systematic improvement of isobutanol production from D-xylose in engineered Saccharomyces cerevisiae. AMB Express 2019; 9:160. [PMID: 31599368 PMCID: PMC6787123 DOI: 10.1186/s13568-019-0885-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/24/2019] [Indexed: 11/11/2022] Open
Abstract
As the importance of reducing carbon emissions as a means to limit the serious effects of global climate change becomes apparent, synthetic biologists and metabolic engineers are looking to develop renewable sources for transportation fuels and petroleum-derived chemicals. In recent years, microbial production of high-energy fuels has emerged as an attractive alternative to the traditional production of transportation fuels. In particular, the Baker’s yeast Saccharomyces cerevisiae, a highly versatile microbial chassis, has been engineered to produce a wide array of biofuels. Nevertheless, a key limitation of S. cerevisiae is its inability to utilize xylose, the second most abundant sugar in lignocellulosic biomass, for both growth and chemical production. Therefore, the development of a robust S. cerevisiae strain that is able to use xylose is of great importance. Here, we engineered S. cerevisiae to efficiently utilize xylose as a carbon source and produce the advanced biofuel isobutanol. Specifically, we screened xylose reductase (XR) and xylose dehydrogenase (XDH) variants from different xylose-metabolizing yeast strains to identify the XR–XDH combination with the highest activity. Overexpression of the selected XR–XDH variants, a xylose-specific sugar transporter, xylulokinase, and isobutanol pathway enzymes in conjunction with the deletions of PHO13 and GRE3 resulted in an engineered strain that is capable of producing isobutanol at a titer of 48.4 ± 2.0 mg/L (yield of 7.0 mg/g d-xylose). This is a 36-fold increase from the previous report by Brat and Boles and, to our knowledge, is the highest isobutanol yield from d-xylose in a microbial system. We hope that our work will set the stage for an economic route for the production of advanced biofuel isobutanol and enable efficient utilization of lignocellulosic biomass.
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24
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Salvador M, Abdulmutalib U, Gonzalez J, Kim J, Smith AA, Faulon JL, Wei R, Zimmermann W, Jimenez JI. Microbial Genes for a Circular and Sustainable Bio-PET Economy. Genes (Basel) 2019; 10:E373. [PMID: 31100963 PMCID: PMC6562992 DOI: 10.3390/genes10050373] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 02/03/2023] Open
Abstract
Plastics have become an important environmental concern due to their durability and resistance to degradation. Out of all plastic materials, polyesters such as polyethylene terephthalate (PET) are amenable to biological degradation due to the action of microbial polyester hydrolases. The hydrolysis products obtained from PET can thereby be used for the synthesis of novel PET as well as become a potential carbon source for microorganisms. In addition, microorganisms and biomass can be used for the synthesis of the constituent monomers of PET from renewable sources. The combination of both biodegradation and biosynthesis would enable a completely circular bio-PET economy beyond the conventional recycling processes. Circular strategies like this could contribute to significantly decreasing the environmental impact of our dependence on this polymer. Here we review the efforts made towards turning PET into a viable feedstock for microbial transformations. We highlight current bottlenecks in degradation of the polymer and metabolism of the monomers, and we showcase fully biological or semisynthetic processes leading to the synthesis of PET from sustainable substrates.
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Affiliation(s)
- Manuel Salvador
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
| | - Umar Abdulmutalib
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
| | - Jaime Gonzalez
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
| | - Juhyun Kim
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
| | - Alex A Smith
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
| | - Jean-Loup Faulon
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
- SYNBIOCHEM Centre, Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK.
- CNRS-UMR8030/Laboratoire iSSB, Université Paris-Saclay, 91000 Évry, France.
| | - Ren Wei
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany.
| | - Wolfgang Zimmermann
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, Leipzig University, 04103 Leipzig, Germany.
| | - Jose I Jimenez
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.
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25
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Wang Y, Xian M, Feng X, Liu M, Zhao G. Biosynthesis of ethylene glycol from d-xylose in recombinant Escherichia coli. Bioengineered 2019; 9:233-241. [PMID: 29865993 PMCID: PMC6984763 DOI: 10.1080/21655979.2018.1478489] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Ethylene glycol (EG) is an important chemical used as antifreeze and a raw material in polyester synthesis. The EG biosynthetic pathway from D-xylose with D-xylonate as key intermediate has some advantages, but showed low EG production. Here, we reconstructed and optimized this pathway in Escherichia coli. In view of the greater intracellular prevalence of NADH, an aldehyde reductase FucO using NADH was employed to convert glycoaldehyde into EG, in replacement of NADPH-dependent reductase YqhD. To suppress the accumulation of by-products acetate and glycolate, two genes arcA and aldA were knocked out. The resultant strain Q2843 produced 72 g/L EG under fed-batch fermentation conditions, with the yield of 0.40 g/g D-xylose and EG productivity of 1.38 g/L/h. The use of NADH-dependent enzyme FucO and by-product elimination significantly improved the performance of EG producing strain, which represented the highest titer, yield and productivity of EG reported so far.
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Affiliation(s)
- Yuhui Wang
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,b School of Life Science , Shandong University , Jinan , China
| | - Mo Xian
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China
| | - Xinjun Feng
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,c Shandong Provincial Key Laboratory of Synthetic Biology , Qingdao , China
| | - Min Liu
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,c Shandong Provincial Key Laboratory of Synthetic Biology , Qingdao , China
| | - Guang Zhao
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,c Shandong Provincial Key Laboratory of Synthetic Biology , Qingdao , China
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26
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Li X, Chen Y, Nielsen J. Harnessing xylose pathways for biofuels production. Curr Opin Biotechnol 2019; 57:56-65. [PMID: 30785001 DOI: 10.1016/j.copbio.2019.01.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 01/04/2019] [Accepted: 01/15/2019] [Indexed: 01/02/2023]
Abstract
Energy security, environmental pollution, and economic development drive the development of alternatives to fossil fuels as an urgent global priority. Lignocellulosic biomass has the potential to contribute to meeting the demand for biofuel production via hydrolysis and fermentation of released sugars, such as glucose, xylose, and arabinose. Construction of robust cell factories requires introducing and rewiring of their metabolism to efficiently use all these sugars. Here, we review recent advances in re-constructing pathways for metabolism of pentoses, with special focus on xylose metabolism in the most widely used cell factories Saccharomyces cerevisiae and Escherichia coli. We also highlight engineering advanced biofuels-synthesis pathways and describes progress toward overcoming the challenges facing adoption of large-scale biofuel production.
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Affiliation(s)
- Xiaowei Li
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Yun Chen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark; Wallenberg Center for Protein Research, Chalmers University of Technology, Gothenburg, Sweden.
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27
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Li W, Chen J, Liu CX, Yuan QP, Li ZJ. Microbial production of glycolate from acetate by metabolically engineered Escherichia coli. J Biotechnol 2019; 291:41-45. [DOI: 10.1016/j.jbiotec.2018.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/06/2018] [Accepted: 12/27/2018] [Indexed: 11/16/2022]
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28
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Salusjärvi L, Havukainen S, Koivistoinen O, Toivari M. Biotechnological production of glycolic acid and ethylene glycol: current state and perspectives. Appl Microbiol Biotechnol 2019; 103:2525-2535. [PMID: 30707252 PMCID: PMC6443609 DOI: 10.1007/s00253-019-09640-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 01/08/2019] [Accepted: 01/09/2019] [Indexed: 12/14/2022]
Abstract
Glycolic acid (GA) and ethylene glycol (EG) are versatile two-carbon organic chemicals used in multiple daily applications. GA and EG are currently produced by chemical synthesis, but their biotechnological production from renewable resources has received a substantial interest. Several different metabolic pathways by using genetically modified microorganisms, such as Escherichia coli, Corynebacterium glutamicum and yeast have been established for their production. As a result, the yield of GA and EG produced from sugars has been significantly improved. Here, we describe the recent advancement in metabolic engineering efforts focusing on metabolic pathways and engineering strategies used for GA and EG production.
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Affiliation(s)
- Laura Salusjärvi
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, P.O. Box 1000, 02044 VTT, Espoo, Finland.
| | - Sami Havukainen
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, P.O. Box 1000, 02044 VTT, Espoo, Finland
| | - Outi Koivistoinen
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, P.O. Box 1000, 02044 VTT, Espoo, Finland
| | - Mervi Toivari
- Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, Tietotie 2, P.O. Box 1000, 02044 VTT, Espoo, Finland
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29
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Harnessing Underground Metabolism for Pathway Development. Trends Biotechnol 2019; 37:29-37. [DOI: 10.1016/j.tibtech.2018.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/17/2018] [Accepted: 08/06/2018] [Indexed: 01/13/2023]
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30
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Escherichia coli as a host for metabolic engineering. Metab Eng 2018; 50:16-46. [DOI: 10.1016/j.ymben.2018.04.008] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/21/2022]
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31
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Lopes LD, Pereira E Silva MDC, Weisberg AJ, Davis EW, Yan Q, Varize CDS, Wu CF, Chang JH, Loper JE, Andreote FD. Genome variations between rhizosphere and bulk soil ecotypes of a Pseudomonas koreensis population. Environ Microbiol 2018; 20:4401-4414. [PMID: 30033663 DOI: 10.1111/1462-2920.14363] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/12/2018] [Accepted: 07/16/2018] [Indexed: 11/28/2022]
Abstract
Bulk soil and rhizosphere are soil compartments selecting different microbial communities. However, it is unknown whether this selection also can change the genome content of specific bacterial taxa, splitting a population in distinct ecotypes. To answer this question we compared the genome sequences of 53 isolates obtained from sugarcane rhizosphere (28) and bulk soil (25). These isolates were previously classified in the Pseudomonas koreensis subgroup of the P. fluorescens complex. Phylogenomics showed a trend of separation between bulk soil and rhizosphere isolates. Discriminant analysis of principal components (DAPC) identified differences in the accessory genome of rhizosphere and bulk soil sub-populations. We found significant changes in gene frequencies distinguishing rhizosphere from bulk soil ecotypes, for example, enrichment of phosphatases and xylose utilization (xut) genes, respectively. Phenotypic assays and deletion of xutA gene indicated that accumulation of xut genes in the bulk soil sub-population provided a higher growth capacity in a d-xylose medium, supporting the corresponding genomic differences. Despite the clear differences distinguishing the two ecotypes, all 53 isolates were classified in a single 16S rRNA gene OTU. Collectively, our results revealed that the gene pool and ecological behavior of a bacterial population can be different for ecotypes living in neighbouring soil habitats.
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Affiliation(s)
- Lucas Dantas Lopes
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil.,Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Michele de C Pereira E Silva
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Edward W Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, 97331, USA
| | - Qing Yan
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Camila de S Varize
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Chih-Feng Wu
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, 97331, USA
| | - Joyce E Loper
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, 97331, USA
| | - Fernando D Andreote
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
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32
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Kim D, Woo HM. Deciphering bacterial xylose metabolism and metabolic engineering of industrial microorganisms for use as efficient microbial cell factories. Appl Microbiol Biotechnol 2018; 102:9471-9480. [PMID: 30238140 DOI: 10.1007/s00253-018-9353-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/23/2018] [Accepted: 08/27/2018] [Indexed: 11/29/2022]
Abstract
The goal of sustainable production of biochemicals and biofuels has driven the engineering of microbial cell as factories that convert low-value substrates to high-value products. Xylose is the second most abundant sugar substrate in lignocellulosic hydrolysates. We analyzed the mechanisms of xylose metabolism using genome sequencing data of 492 industrially relevant bacterial species in the mini-review. The analysis revealed the xylose isomerase and Weimberg pathways as the major routes across diverse routes of bacterial xylose metabolism. In addition, we discuss recent developments in metabolic engineering of xylose metabolism in industrial microorganisms. Genome-scale analyses have revealed xylose pathway-specific flux landscapes. Overall, a comprehensive understanding of bacterial xylose metabolism could be useful for the feasible development of microbial cell factories.
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Affiliation(s)
- Donghyuk Kim
- School of Energy and Chemical Engineering and School of Biological Sciences, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulsan, 44919, Republic of Korea
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea.
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33
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Frazão CR, Maton V, François JM, Walther T. Development of a Metabolite Sensor for High-Throughput Detection of Aldehydes in Escherichia Coli. Front Bioeng Biotechnol 2018; 6:118. [PMID: 30191150 PMCID: PMC6115493 DOI: 10.3389/fbioe.2018.00118] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 08/03/2018] [Indexed: 01/31/2023] Open
Abstract
We have developed a fluorescence-based metabolite sensor enabling in vivo detection of various aldehydes of biotechnological interest in Escherichia coli. YqhC is a transcriptional regulator that is known to be involved in the upregulation of the yqhD-dgkA operon in the presence of aldehydes. We took advantage of this property by constructing a bi-modular biosensor, in which a sensing module constitutively expresses yqhC while a reporter module drives the expression of the syfp2 reporter gene that is put under control of the yqhD promoter. The sensitivity of the sensor has been optimized by engineering the 5′-UTRs of both the sensing and the reporter modules resulting in a 70-fold gain of fluorescence in response to the model compound glycolaldehyde at 5 mM. The optimized sensor further responded to other aldehydes when supplemented to the cultivation medium at concentrations of 1–10 mM. We furthermore showed that this metabolite sensor was functional in vivo as it responded to the presence of glycoladehyde that is specifically produced upon induction of a synthetic xylulose-1-phosphate pathway expressed in E. coli. This bi-modular sensor can therefore be employed as an exquisite tool for FACS-based ultra-high-throughput screening of aldehyde (over) producing enzymes.
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Affiliation(s)
- Cláudio R Frazão
- LISBP, CNRS, INRA, INSA, Université de Toulouse, Toulouse, France
| | - Victor Maton
- LISBP, CNRS, INRA, INSA, Université de Toulouse, Toulouse, France
| | - Jean M François
- LISBP, CNRS, INRA, INSA, Université de Toulouse, Toulouse, France.,Toulouse White Biotechnology (TWB), Toulouse, France
| | - Thomas Walther
- LISBP, CNRS, INRA, INSA, Université de Toulouse, Toulouse, France
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34
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Camarasa C, Chiron H, Daboussi F, Della Valle G, Dumas C, Farines V, Floury J, Gagnaire V, Gorret N, Leonil J, Mouret JR, O'Donohue MJ, Sablayrolles JM, Salmon JM, Saulnier L, Truan G. INRA's research in industrial biotechnology: For food, chemicals, materials and fuels. INNOV FOOD SCI EMERG 2018. [DOI: 10.1016/j.ifset.2017.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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35
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Liu M, Ding Y, Xian M, Zhao G. Metabolic engineering of a xylose pathway for biotechnological production of glycolate in Escherichia coli. Microb Cell Fact 2018; 17:51. [PMID: 29592804 PMCID: PMC5874992 DOI: 10.1186/s12934-018-0900-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glycolate is a valuable chemical with extensive applications in many different fields. The traditional methods to synthesize glycolate are quite expensive and toxic. So, the biotechnological production of glycolate from sustainable feedstocks is of interest for its potential economic and environmental advantages. D-Xylose is the second most abundant sugar in nature and accounts for 18-30% of sugar in lignocellulose. New routes for the conversion of xylose to glycolate were explored. RESULTS Overexpression of aceA and ghrA and deletion of aceB in Escherichia coli were examined for glycolate production from xylose, but the conversion was initially ineffective. Then, a new route for glycolate production was established in E. coli by introducing NAD+-dependent xylose dehydrogenase (xdh) and xylonolactonase (xylC) from Caulobacter crescentus. The constructed engineered strain Q2562 produced 28.82 ± 0.56 g/L glycolate from xylose with 0.60 ± 0.01 g/L/h productivity and 0.38 ± 0.07 g/g xylose yield. However, 27.18 ± 2.13 g/L acetate was accumulated after fermentation. Deletions of iclR and ackA were used to overcome the acetate excretion. An ackA knockout resulted in about 66% decrease in acetate formation. The final engineered strain Q2742 produced 43.60 ± 1.22 g/L glycolate, with 0.91 ± 0.02 g/L/h productivity and 0.46 ± 0.03 g/g xylose yield. CONCLUSIONS A new route for glycolate production from xylose was established, and an engineered strain Q2742 was constructed from this new explored pathway. The engineering strain showed the highest reported productivity of glycolate to date. This research opened up a new prospect for bio-refinery of xylose and an alternative choice for industrial production of glycolate.
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Affiliation(s)
- Min Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao, 266101, China
| | - Yamei Ding
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China.
| | - Guang Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China. .,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao, 266101, China.
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36
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Engineering Escherichia coli for glycolic acid production from D-xylose through the Dahms pathway and glyoxylate bypass. Appl Microbiol Biotechnol 2018; 102:2179-2189. [DOI: 10.1007/s00253-018-8744-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 12/20/2017] [Accepted: 12/26/2017] [Indexed: 11/25/2022]
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37
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Salusjärvi L, Toivari M, Vehkomäki ML, Koivistoinen O, Mojzita D, Niemelä K, Penttilä M, Ruohonen L. Production of ethylene glycol or glycolic acid from D-xylose in Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2017; 101:8151-8163. [PMID: 29038973 DOI: 10.1007/s00253-017-8547-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/05/2017] [Accepted: 09/17/2017] [Indexed: 11/26/2022]
Abstract
The important platform chemicals ethylene glycol and glycolic acid were produced via the oxidative D-xylose pathway in the yeast Saccharomyces cerevisiae. The expression of genes encoding D-xylose dehydrogenase (XylB) and D-xylonate dehydratase (XylD) from Caulobacter crescentus and YagE or YjhH aldolase and aldehyde dehydrogenase AldA from Escherichia coli enabled glycolic acid production from D-xylose up to 150 mg/L. In strains expressing only xylB and xylD, 29 mg/L 2-keto-3-deoxyxylonic acid [(S)-4,5-dihydroxy-2-oxopentanoic acid] (2K3DXA) was produced and D-xylonic acid accumulated to ca. 9 g/L. A significant amount of D-xylonic acid (ca. 14%) was converted to 3-deoxypentonic acid (3DPA), and also, 3,4-dihydroxybutyric acid was formed. 2K3DXA was further converted to glycolaldehyde when genes encoding by either YagE or YjhH aldolase from E. coli were expressed. Reduction of glycolaldehyde to ethylene glycol by an endogenous aldo-keto reductase activity resulted further in accumulation of ethylene glycol of 14 mg/L. The possibility of simultaneous production of lactic and glycolic acids was evaluated by expression of gene encoding lactate dehydrogenase ldhL from Lactobacillus helveticus together with aldA. Interestingly, this increased the accumulation of glycolic acid to 1 g/L. The D-xylonate dehydratase activity in yeast was notably low, possibly due to inefficient Fe-S cluster synthesis in the yeast cytosol, and leading to D-xylonic acid accumulation. The dehydratase activity was significantly improved by targeting its expression to mitochondria or by altering the Fe-S cluster metabolism of the cells with FRA2 deletion.
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Affiliation(s)
- Laura Salusjärvi
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
| | - Mervi Toivari
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Maija-Leena Vehkomäki
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Outi Koivistoinen
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Dominik Mojzita
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Klaus Niemelä
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Merja Penttilä
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
| | - Laura Ruohonen
- VTT Technical Research Centre of Finland Ltd., Solutions for Natural Resources and Environment, Tietotie 2, P.O. Box 1000, FI-02044 VTT, Espoo, Finland
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38
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King JR, Woolston BM, Stephanopoulos G. Designing a New Entry Point into Isoprenoid Metabolism by Exploiting Fructose-6-Phosphate Aldolase Side Reactivity of Escherichia coli. ACS Synth Biol 2017; 6:1416-1426. [PMID: 28375628 DOI: 10.1021/acssynbio.7b00072] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 2C-methyl-d-erythritol-4-phosphate (MEP) pathway in Escherichia coli has been highlighted for its potential to provide access to myriad isoprenoid chemicals of industrial and therapeutic relevance and discover antibiotic targets to treat microbial human pathogens. Here, we describe a metabolic engineering strategy for the de novo construction of a biosynthetic pathway that produces 1-dexoxy-d-xylulose-5-phosphate (DXP), the precursor metabolite of the MEP pathway, from the simple and renewable starting materials d-arabinose and hydroxyacetone. Unlike most metabolic engineering efforts in which cell metabolism is reprogrammed with enzymes that are highly specific to their desired reaction, we highlight the promiscuous activity of the native E. coli fructose-6-phosphate aldolase as central to the metabolic rerouting of carbon to DXP. We use mass spectrometric isotopomer analysis of intracellular metabolites to show that the engineered pathway is able to support in vivo DXP biosynthesis in E. coli. The engineered DXP synthesis is further able to rescue cells that were chemically inhibited in their ability to produce DXP and to increase terpene titers in strains harboring the non-native lycopene pathway. In addition to providing an alternative metabolic pathway to produce isoprenoids, the results here highlight the potential role of pathway evolution to circumvent metabolic inhibitors in the development of microbial antibiotic resistance.
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Affiliation(s)
- Jason R. King
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
| | - Benjamin M. Woolston
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
| | - Gregory Stephanopoulos
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, United States
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39
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Construction of a synthetic metabolic pathway for biosynthesis of the non-natural methionine precursor 2,4-dihydroxybutyric acid. Nat Commun 2017. [PMID: 28631755 PMCID: PMC5481828 DOI: 10.1038/ncomms15828] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
2,4-Dihydroxybutyric acid (DHB) is a molecule with considerable potential as a versatile chemical synthon. Notably, it may serve as a precursor for chemical synthesis of the methionine analogue 2-hydroxy-4-(methylthio)butyrate, thus, targeting a considerable market in animal nutrition. However, no natural metabolic pathway exists for the biosynthesis of DHB. Here we have therefore conceived a three-step metabolic pathway for the synthesis of DHB starting from the natural metabolite malate. The pathway employs previously unreported malate kinase, malate semialdehyde dehydrogenase and malate semialdehyde reductase activities. The kinase and semialdehyde dehydrogenase activities were obtained by rational design based on structural and mechanistic knowledge of candidate enzymes acting on sterically cognate substrates. Malate semialdehyde reductase activity was identified from an initial screening of several natural enzymes, and was further improved by rational design. The pathway was expressed in a minimally engineered Escherichia coli strain and produces 1.8 g l-1 DHB with a molar yield of 0.15.
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40
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Liu G, Li B, Li C, Yuan Y. Enhancement of Simultaneous Xylose and Glucose Utilization by Regulating ZWF1 and PGI1 in Saccharomyces Cerevisiae. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s12209-017-0048-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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41
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Jo S, Yoon J, Lee SM, Um Y, Han SO, Woo HM. Modular pathway engineering of Corynebacterium glutamicum to improve xylose utilization and succinate production. J Biotechnol 2017; 258:69-78. [PMID: 28153765 DOI: 10.1016/j.jbiotec.2017.01.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/24/2017] [Accepted: 01/27/2017] [Indexed: 11/26/2022]
Abstract
Xylose-negative Corynebacterium glutamicum has been engineered to utilize xylose as the sole carbon source via either the xylose isomerase (XI) pathway or the Weimberg pathway. Heterologous expression of xylose isomerase and overexpression of a gene encoding for xylulose kinase enabled efficient xylose utilization. In this study, we show that two functionally-redundant transcriptional regulators (GntR1 and GntR2) present on xylose repress the pentose phosphate pathway genes. For efficient xylose utilization, pentose phosphate pathway genes and a phosphoketolase gene were overexpressed with the XI pathway in C. glutamicum. Overexpression of the genes encoding for transaldolase (Tal), 6-phosphogluconate dehydrogenase (Gnd), or phosphoketolase (XpkA) enhanced the growth and xylose consumption rates compared to the wild-type with the XI pathway alone. However, co-expression of these genes did not have a synergetic effect on xylose utilization. For the succinate production from xylose, overexpression of the tal gene with the XI pathway in a succinate-producing strain improved xylose utilization and increased the specific succinate production rate by 2.5-fold compared to wild-type with the XI pathway alone. Thus, overexpression of the tal, gnd, or xpkA gene could be helpful for engineering C. glutamicum toward production of value-added chemicals with efficient xylose utilization.
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Affiliation(s)
- Suah Jo
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jinkyung Yoon
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
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42
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Gonzalez JE, Antoniewicz MR. Tracing metabolism from lignocellulosic biomass and gaseous substrates to products with stable-isotopes. Curr Opin Biotechnol 2016; 43:86-95. [PMID: 27780112 DOI: 10.1016/j.copbio.2016.10.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/03/2016] [Accepted: 10/05/2016] [Indexed: 12/12/2022]
Abstract
Engineered microbes offer a practical and sustainable alternative to traditional industrial approaches. To increase the economic feasibility of biological processes, microbial isolates are engineered to take up inexpensive feedstocks (including lignocellulosic biomass, syngas, methane, and carbon dioxide), and convert them into substrates of central metabolism and further into value-added products. To trace the metabolism of these feedstocks into products, isotopic tracers are applied together with isotopomer analysis techniques such as 13C-metabolic flux analysis to provide a detailed picture of pathway utilization. Flux data is then integrated with kinetic models and constraint-based approaches to identify metabolic bottlenecks, propose novel metabolic engineering strategies, and improve process performance.
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Affiliation(s)
- Jacqueline E Gonzalez
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA.
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43
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Alkim C, Trichez D, Cam Y, Spina L, François JM, Walther T. The synthetic xylulose-1 phosphate pathway increases production of glycolic acid from xylose-rich sugar mixtures. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:201. [PMID: 27679669 PMCID: PMC5029101 DOI: 10.1186/s13068-016-0610-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/01/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Glycolic acid (GA) is a two-carbon hydroxyacid with applications in the cosmetic, textile, and medical industry. Microbial GA production from all sugars can be achieved by engineering the natural glyoxylate shunt. The synthetic (d)-xylulose-1 phosphate (X1P) pathway provides a complementary route to produce GA from (d)-xylose. The simultaneous operation of the X1P and glyoxylate pathways increases the theoretical GA yield from xylose by 20 %, which may strongly improve GA production from hemicellulosic hydrolysates. RESULTS We herein describe the construction of an E. coli strain that produces GA via the glyoxylate pathway at a yield of 0.31 , 0.29 , and 0.37 g/g from glucose, xylose, or a mixture of glucose and xylose (mass ratio: 33:66 %), respectively. When the X1P pathway operates in addition to the glyoxylate pathway, the GA yields on the three substrates are, respectively, 0.39 , 0.43 , and 0.47 g/g. Upon constitutive expression of the sugar permease GalP, the GA yield of the strain which simultaneously operates the glyoxylate and X1P pathways further increases to 0.63 g/g when growing on the glucose/xylose mixture. Under these conditions, the GA yield on the xylose fraction of the sugar mixture reaches 0.75 g/g, which is the highest yield reported to date. CONCLUSIONS These results demonstrate that the synthetic X1P pathway has a very strong potential to improve GA production from xylose-rich hemicellulosic hydrolysates.
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Affiliation(s)
- Ceren Alkim
- LISBP, CNRS, INRA, INSA, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- TWB, 3 rue Ariane, 31520 Ramonville-St. Agne, France
| | - Debora Trichez
- LISBP, CNRS, INRA, INSA, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- TWB, 3 rue Ariane, 31520 Ramonville-St. Agne, France
| | - Yvan Cam
- LISBP, CNRS, INRA, INSA, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- TWB, 3 rue Ariane, 31520 Ramonville-St. Agne, France
| | - Lucie Spina
- LISBP, CNRS, INRA, INSA, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- TWB, 3 rue Ariane, 31520 Ramonville-St. Agne, France
| | - Jean Marie François
- LISBP, CNRS, INRA, INSA, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- TWB, 3 rue Ariane, 31520 Ramonville-St. Agne, France
| | - Thomas Walther
- LISBP, CNRS, INRA, INSA, Université de Toulouse, 135 Avenue de Rangueil, 31077 Toulouse, France
- TWB, 3 rue Ariane, 31520 Ramonville-St. Agne, France
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44
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Chomvong K, Bauer S, Benjamin DI, Li X, Nomura DK, Cate JHD. Bypassing the Pentose Phosphate Pathway: Towards Modular Utilization of Xylose. PLoS One 2016; 11:e0158111. [PMID: 27336308 PMCID: PMC4918971 DOI: 10.1371/journal.pone.0158111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/12/2016] [Indexed: 12/22/2022] Open
Abstract
The efficient use of hemicellulose in the plant cell wall is critical for the economic conversion of plant biomass to renewable fuels and chemicals. Previously, the yeast Saccharomyces cerevisiae has been engineered to convert the hemicellulose-derived pentose sugars xylose and arabinose to d-xylulose-5-phosphate for conversion via the pentose phosphate pathway (PPP). However, efficient pentose utilization requires PPP optimization and may interfere with its roles in NADPH and pentose production. Here, we developed an alternative xylose utilization pathway that largely bypasses the PPP. In the new pathway, d-xylulose is converted to d-xylulose-1-phosphate, a novel metabolite to S. cerevisiae, which is then cleaved to glycolaldehyde and dihydroxyacetone phosphate. This synthetic pathway served as a platform for the biosynthesis of ethanol and ethylene glycol. The use of d-xylulose-1-phosphate as an entry point for xylose metabolism opens the way for optimizing chemical conversion of pentose sugars in S. cerevisiae in a modular fashion.
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Affiliation(s)
- Kulika Chomvong
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, United States of America
| | - Stefan Bauer
- Energy Biosciences Institute, Berkeley, CA, United States of America
| | - Daniel I. Benjamin
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, United States of America
| | - Xin Li
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, United States of America
| | - Daniel K. Nomura
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, United States of America
| | - Jamie H. D. Cate
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, United States of America
- Department of Chemistry, University of California, Berkeley, CA, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
- * E-mail:
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Alkim C, Cam Y, Trichez D, Auriol C, Spina L, Vax A, Bartolo F, Besse P, François JM, Walther T. Optimization of ethylene glycol production from (D)-xylose via a synthetic pathway implemented in Escherichia coli. Microb Cell Fact 2015; 14:127. [PMID: 26336892 PMCID: PMC4559361 DOI: 10.1186/s12934-015-0312-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 08/04/2015] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Ethylene glycol (EG) is a bulk chemical that is mainly used as an anti-freezing agent and a raw material in the synthesis of plastics. Production of commercial EG currently exclusively relies on chemical synthesis using fossil resources. Biochemical production of ethylene glycol from renewable resources may be more sustainable. RESULTS Herein, a synthetic pathway is described that produces EG in Escherichia coli through the action of (D)-xylose isomerase, (D)-xylulose-1-kinase, (D)-xylulose-1-phosphate aldolase, and glycolaldehyde reductase. These reactions were successively catalyzed by the endogenous xylose isomerase (XylA), the heterologously expressed human hexokinase (Khk-C) and aldolase (Aldo-B), and an endogenous glycolaldehyde reductase activity, respectively, which we showed to be encoded by yqhD. The production strain was optimized by deleting the genes encoding for (D)-xylulose-5 kinase (xylB) and glycolaldehyde dehydrogenase (aldA), and by overexpressing the candidate glycolaldehyde reductases YqhD, GldA, and FucO. The strain overproducing FucO was the best EG producer reaching a molar yield of 0.94 in shake flasks, and accumulating 20 g/L EG with a molar yield and productivity of 0.91 and 0.37 g/(L.h), respectively, in a controlled bioreactor under aerobic conditions. CONCLUSIONS We have demonstrated the feasibility to produce EG from (D)-xylose via a synthetic pathway in E. coli at approximately 90 % of the theoretical yield.
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Affiliation(s)
- Ceren Alkim
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France. .,TWB, 3 rue Ariane, 31520, Ramonville-St. Agnes, France.
| | - Yvan Cam
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France. .,TWB, 3 rue Ariane, 31520, Ramonville-St. Agnes, France.
| | - Debora Trichez
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France.
| | - Clément Auriol
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France. .,TWB, 3 rue Ariane, 31520, Ramonville-St. Agnes, France.
| | - Lucie Spina
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France.
| | - Amélie Vax
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France.
| | - François Bartolo
- UMR CNRS 5219, Institut de Mathématiques de Toulouse, INSA, Université de Toulouse, Toulouse, France.
| | - Philippe Besse
- UMR CNRS 5219, Institut de Mathématiques de Toulouse, INSA, Université de Toulouse, Toulouse, France.
| | - Jean Marie François
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France. .,TWB, 3 rue Ariane, 31520, Ramonville-St. Agnes, France.
| | - Thomas Walther
- INSA, UPS, INP, LISBP, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse, France. .,UMR792 Ingénierie des Systèmes Biologiques et des Procédés (LISBP), INRA, Toulouse, France. .,CNRS, UMR5504, Toulouse, France. .,TWB, 3 rue Ariane, 31520, Ramonville-St. Agnes, France.
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