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Lin F, Li W, Wang D, Hu G, Qin Z, Xia X, Hu L, Liu X, Luo R. Advances in succinic acid production: the enhancement of CO 2 fixation for the carbon sequestration benefits. Front Bioeng Biotechnol 2024; 12:1392414. [PMID: 38605985 PMCID: PMC11007169 DOI: 10.3389/fbioe.2024.1392414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 03/18/2024] [Indexed: 04/13/2024] Open
Abstract
Succinic acid (SA), one of the 12 top platform chemicals produced from biomass, is a precursor of various high value-added derivatives. Specially, 1 mol CO2 is assimilated in 1 mol SA biosynthetic route under anaerobic conditions, which helps to achieve carbon reduction goals. In this review, methods for enhanced CO2 fixation in SA production and utilization of waste biomass for SA production are reviewed. Bioelectrochemical and bioreactor coupling systems constructed with off-gas reutilization to capture CO2 more efficiently were highlighted. In addition, the techno-economic analysis and carbon sequestration benefits for the synthesis of bio-based SA from CO2 and waste biomass are analyzed. Finally, a droplet microfluidics-based high-throughput screening technique applied to the future bioproduction of SA is proposed as a promising approach.
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Affiliation(s)
| | | | - Dan Wang
- Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
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2
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Campbell RP, Whittington AC, Zorio DAR, Miller BG. Recruitment of a Middling Promiscuous Enzyme Drives Adaptive Metabolic Evolution in Escherichia coli. Mol Biol Evol 2023; 40:msad202. [PMID: 37708398 PMCID: PMC10519446 DOI: 10.1093/molbev/msad202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/16/2023] Open
Abstract
A key step in metabolic pathway evolution is the recruitment of promiscuous enzymes to perform new functions. Despite the recognition that promiscuity is widespread in biology, factors dictating the preferential recruitment of one promiscuous enzyme over other candidates are unknown. Escherichia coli contains four sugar kinases that are candidates for recruitment when the native glucokinase machinery is deleted-allokinase (AlsK), manno(fructo)kinase (Mak), N-acetylmannosamine kinase (NanK), and N-acetylglucosamine kinase (NagK). The catalytic efficiencies of these enzymes are 103- to 105-fold lower than native glucokinases, ranging from 2,400 M-1 s-1 for the most active candidate, NagK, to 15 M-1 s-1 for the least active candidate, AlsK. To investigate the relationship between catalytic activities of promiscuous enzymes and their recruitment, we performed adaptive evolution of a glucokinase-deficient E. coli strain to restore glycolytic metabolism. We observed preferential recruitment of NanK via a trajectory involving early mutations that facilitate glucose uptake and amplify nanK transcription, followed by nonsynonymous substitutions in NanK that enhance the enzyme's promiscuous glucokinase activity. These substitutions reduced the native activity of NanK and reduced organismal fitness during growth on an N-acetylated carbon source, indicating that enzyme recruitment comes at a cost for growth on other substrates. Notably, the two most active candidates, NagK and Mak, were not recruited, suggesting that catalytic activity alone does not dictate evolutionary outcomes. The results highlight our lack of knowledge regarding biological drivers of enzyme recruitment and emphasize the need for a systems-wide approach to identify factors facilitating or constraining this important adaptive process.
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Affiliation(s)
- Ryan P Campbell
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
| | - A Carl Whittington
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Diego A R Zorio
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Brian G Miller
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
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3
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Zhou S, Zhang M, Zhu L, Zhao X, Chen J, Chen W, Chang C. Hydrolysis of lignocellulose to succinic acid: a review of treatment methods and succinic acid applications. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:1. [PMID: 36593503 PMCID: PMC9806916 DOI: 10.1186/s13068-022-02244-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/08/2022] [Indexed: 01/03/2023]
Abstract
Succinic acid (SA) is an intermediate product of the tricarboxylic acid cycle (TCA) and is one of the most significant platform chemicals for the production of various derivatives with high added value. Due to the depletion of fossil raw materials and the demand for eco-friendly energy sources, SA biosynthesis from renewable energy sources is gaining attention for its environmental friendliness. This review comprehensively analyzes strategies for the bioconversion of lignocellulose to SA based on the lignocellulose pretreatment processes and cellulose hydrolysis and fermentation principles and highlights the research progress on acid production and SA utilization under different microbial culture conditions. In addition, the fermentation efficiency of different microbial strains for the production of SA and the main challenges were analyzed. The future application directions of SA derivatives were pointed out. It is expected that this research will provide a reference for the optimization of SA production from lignocellulose.
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Affiliation(s)
- Shuzhen Zhou
- grid.207374.50000 0001 2189 3846College of Chemical Engineering, Zhengzhou University, Zhengzhou, China
| | - Miaomiao Zhang
- grid.207374.50000 0001 2189 3846College of Chemical Engineering, Zhengzhou University, Zhengzhou, China
| | - Linying Zhu
- grid.207374.50000 0001 2189 3846College of Management Engineering, Zhengzhou University, Zhengzhou, China
| | - Xiaoling Zhao
- grid.207374.50000 0001 2189 3846College of Chemical Engineering, Zhengzhou University, Zhengzhou, China ,grid.454889.cState Key Laboratory of Motor Vehicle Biofuel Technology, Nanyang, China ,Henan Center for Outstanding Overseas Scientists, Zhengzhou, China
| | - Junying Chen
- grid.207374.50000 0001 2189 3846College of Chemical Engineering, Zhengzhou University, Zhengzhou, China ,grid.454889.cState Key Laboratory of Motor Vehicle Biofuel Technology, Nanyang, China ,Henan Center for Outstanding Overseas Scientists, Zhengzhou, China
| | - Wei Chen
- Henan Key Laboratory of Green Manufacturing of Biobased Chemicals, Puyang, China
| | - Chun Chang
- grid.207374.50000 0001 2189 3846College of Chemical Engineering, Zhengzhou University, Zhengzhou, China ,grid.454889.cState Key Laboratory of Motor Vehicle Biofuel Technology, Nanyang, China ,Henan Center for Outstanding Overseas Scientists, Zhengzhou, China
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4
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Zhu X, Fan F, Qiu H, Shao M, Li D, Yu Y, Bi C, Zhang X. New xylose transporters support the simultaneous consumption of glucose and xylose in Escherichia coli. MLIFE 2022; 1:156-170. [PMID: 38817680 PMCID: PMC10989795 DOI: 10.1002/mlf2.12021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/11/2022] [Accepted: 04/14/2022] [Indexed: 06/01/2024]
Abstract
Glucose and xylose are two major components of lignocellulose. Simultaneous consumption of glucose and xylose is critical for engineered microorganisms to produce fuels and chemicals from lignocellulosic biomass. Although many production limitations have been resolved, glucose-induced inhibition of xylose transport remains a challenge. In this study, a cell growth-based screening strategy was designed to identify xylose transporters uninhibited by glucose. The glucose pathway was genetically blocked in Escherichia coli so that glucose functions only as an inhibitor and cells need xylose as the carbon source for survival. Through adaptive evolution, omics analysis and reverse metabolic engineering, a new phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS) galactitol transporter (GalABC, encoded by EcolC_1640, EcolC_1641, and EcolC_1642 genes) that is not inhibited by glucose was identified. Inactivation of adenylate cyclase led to increased expression of the EcolC_1642 gene, and a point mutation in gene EcolC_1642 (N13S) further enhanced xylose transport. During the second round of gene mining, AraE and a new ABC transporter (AraFGH) of xylose were identified. A point mutation in the transcription regulator araC (L156I) caused increased expression of araE and araFGH genes without arabinose induction, and a point mutation in araE (D223Y) further enhanced xylose transport. These newly identified xylose transporters can support the simultaneous consumption of glucose and xylose and have potential use in producing chemicals from lignocellulose.
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Affiliation(s)
- Xinna Zhu
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
| | - Feiyu Fan
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
| | - Huanna Qiu
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
- College of BiotechnologyTianjin University of Sciences and TechnologyTianjinChina
| | - Mengyao Shao
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
- College of BiotechnologyTianjin University of Sciences and TechnologyTianjinChina
| | - Di Li
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
- College of BiotechnologyTianjin University of Sciences and TechnologyTianjinChina
| | - Yong Yu
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
- University of Chinese Academy of SciencesBeijingChina
| | - Changhao Bi
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
| | - Xueli Zhang
- Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
- Key Laboratory of Systems Microbial BiotechnologyChinese Academy of SciencesTianjinChina
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5
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Ioannidou SM, Ladakis D, Moutousidi E, Dheskali E, Kookos IK, Câmara-Salim I, Moreira MT, Koutinas A. Techno-economic risk assessment, life cycle analysis and life cycle costing for poly(butylene succinate) and poly(lactic acid) production using renewable resources. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150594. [PMID: 34610401 DOI: 10.1016/j.scitotenv.2021.150594] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/31/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
The sustainable production of poly(lactic acid) (PLA) or poly(butylene succinate) (PBS) from corn glucose syrup, corn stover and sugar beet pulp (SBP) have been assessed via process design, preliminary techno-economic evaluation, life cycle assessment and life cycle costing (LCC). Cost-competitive PLA and PBS production can be achieved in a SBP-based biorefinery, including separation of crude pectin-rich extract as co-product, leading to minimum selling prices of $1.14/kgPLA and $1.37/kgPBS. Acidification Potential, Eutrophication Potential and Human Toxicity Potential are lower when SBP is used. The LCC of PLA ($1.42/kgPLA) and PBS ($1.72/kgPBS) production from SBP are lower than biaxial oriented polypropylene (BOPP, $1.66/kg) and general purpose polystyrene (GPPS, $2.04/kg) at pectin-rich extract market prices of $3/kg and $4/kg, respectively. Techno-economic risk assessment via Monte-Carlo simulations showed that PLA and PBS could be produced from SBP at the market prices of BOPP ($1.4/kg) and GPPS ($1.72/kg) with 100% probability to achieve a positive Net Present Value at pectin-rich extract market prices of $3/kg and $4/kg, respectively. This study demonstrated that SBP-based biorefinery development ensures sustainable production of PLA and PBS as compared to fossil-derived counterparts and single product bioprocesses using glucose syrup and corn stover.
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Affiliation(s)
- Sofia Maria Ioannidou
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece
| | - Dimitrios Ladakis
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece
| | - Eleni Moutousidi
- Department of Chemical Engineering, University of Patras, Rio, 26504 Patras, Greece
| | - Endrit Dheskali
- Department of Chemical Engineering, University of Patras, Rio, 26504 Patras, Greece
| | - Ioannis K Kookos
- Department of Chemical Engineering, University of Patras, Rio, 26504 Patras, Greece
| | - Iana Câmara-Salim
- Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - María Teresa Moreira
- Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Apostolis Koutinas
- Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.
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6
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Tafur Rangel AE, Oviedo AG, Mojica FC, Gómez JM, Gónzalez Barrios AF. Development of an integrating systems metabolic engineering and bioprocess modeling approach for rational strain improvement. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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Shi A, Broach JR. Microbial adaptive evolution. J Ind Microbiol Biotechnol 2021; 49:6407523. [PMID: 34673973 PMCID: PMC9118994 DOI: 10.1093/jimb/kuab076] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/27/2021] [Indexed: 01/08/2023]
Abstract
Bacterial species can adapt to significant changes in their environment by mutation followed by selection, a phenomenon known as “adaptive evolution.” With the development of bioinformatics and genetic engineering, research on adaptive evolution has progressed rapidly, as have applications of the process. In this review, we summarize various mechanisms of bacterial adaptive evolution, the technologies used for studying it, and successful applications of the method in research and industry. We particularly highlight the contributions of Dr. L. O. Ingram. Microbial adaptive evolution has significant impact on our society not only from its industrial applications, but also in the evolution, emergence, and control of various pathogens.
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Affiliation(s)
- Aiqin Shi
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - James R Broach
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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8
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Tenhaef N, Kappelmann J, Eich A, Weiske M, Brieß L, Brüsseler C, Marienhagen J, Wiechert W, Noack S. Microaerobic growth-decoupled production of α-ketoglutarate and succinate from xylose in a one-pot process using Corynebacterium glutamicum. Biotechnol J 2021; 16:e2100043. [PMID: 34089621 DOI: 10.1002/biot.202100043] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND Lignocellulosic biomass is the most abundant raw material on earth. Its efficient use for novel bio-based materials is essential for an emerging bioeconomy. Possible building blocks for such materials are the key TCA-cycle intermediates α-ketoglutarate and succinate. These organic acids have a wide range of potential applications, particularly in use as monomers for established or novel biopolymers. Recently, Corynebacterium glutamicum was successfully engineered and evolved towards an improved utilization of d-xylose via the Weimberg pathway, yielding the strain WMB2evo . The Weimberg pathway enables a carbon-efficient C5-to-C5 conversion of d-xylose to α-ketoglutarate and a shortcut route to succinate as co-product in a one-pot process. METHODS AND RESULTS C. glutamicum WMB2evo was grown under dynamic microaerobic conditions on d-xylose, leading to the formation of comparably high amounts of succinate and only small amounts of α-ketoglutarate. Subsequent carbon isotope labeling experiments verified the targeted production route for both products in C. glutamicum WMB2evo . Fed-batch process development was initiated and the effect of oxygen supply and feeding strategy for a growth-decoupled co-production of α-ketoglutarate and succinate were studied in detail. The finally established fed-batch production process resulted in the formation of 78.4 mmol L-1 (11.45 g L-1 ) α-ketoglutarate and 96.2 mmol L-1 (11.36 g L-1 ) succinate. CONCLUSION The developed one-pot process represents a promising approach for the combined supply of bio-based α-ketoglutarate and succinate. Future work will focus on tailor-made down-stream processing of both organic acids from the fermentation broth to enable their application as building blocks in chemical syntheses. Alternatively, direct conversion of one or both acids via whole-cell or cell-free enzymatic approaches can be envisioned; thus, extending the network of value chains starting from cheap and renewable d-xylose.
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Affiliation(s)
- Niklas Tenhaef
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Jannick Kappelmann
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Currenta GmbH & Co. OHG, Leverkusen, Germany
| | - Arabel Eich
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Marc Weiske
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Lisette Brieß
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Christian Brüsseler
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Jan Marienhagen
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Jülich, Germany.,Institute of Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Wolfgang Wiechert
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Jülich, Germany.,Computational Systems Biotechnology (AVT.CSB), RWTH Aachen University, Aachen, Germany
| | - Stephan Noack
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany.,Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Jülich, Germany
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9
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Flores AD, Choi HG, Martinez R, Onyeabor M, Ayla EZ, Godar A, Machas M, Nielsen DR, Wang X. Catabolic Division of Labor Enhances Production of D-Lactate and Succinate From Glucose-Xylose Mixtures in Engineered Escherichia coli Co-culture Systems. Front Bioeng Biotechnol 2020; 8:329. [PMID: 32432089 PMCID: PMC7214542 DOI: 10.3389/fbioe.2020.00329] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/25/2020] [Indexed: 01/01/2023] Open
Abstract
Although biological upgrading of lignocellulosic sugars represents a promising and sustainable route to bioplastics, diverse and variable feedstock compositions (e.g., glucose from the cellulose fraction and xylose from the hemicellulose fraction) present several complex challenges. Specifically, sugar mixtures are often incompletely metabolized due to carbon catabolite repression while composition variability further complicates the optimization of co-utilization rates. Benefiting from several unique features including division of labor, increased metabolic diversity, and modularity, synthetic microbial communities represent a promising platform with the potential to address persistent bioconversion challenges. In this work, two unique and catabolically orthogonal Escherichia coli co-cultures systems were developed and used to enhance the production of D-lactate and succinate (two bioplastic monomers) from glucose-xylose mixtures (100 g L-1 total sugars, 2:1 by mass). In both cases, glucose specialist strains were engineered by deleting xylR (encoding the xylose-specific transcriptional activator, XylR) to disable xylose catabolism, whereas xylose specialist strains were engineered by deleting several key components involved with glucose transport and phosphorylation systems (i.e., ptsI, ptsG, galP, glk) while also increasing xylose utilization by introducing specific xylR mutations. Optimization of initial population ratios between complementary sugar specialists proved a key design variable for each pair of strains. In both cases, ∼91% utilization of total sugars was achieved in mineral salt media by simple batch fermentation. High product titer (88 g L-1 D-lactate, 84 g L-1 succinate) and maximum productivity (2.5 g L-1 h-1 D-lactate, 1.3 g L-1 h-1 succinate) and product yield (0.97 g g-total sugar-1 for D-lactate, 0.95 g g-total sugar-1 for succinate) were also achieved.
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Affiliation(s)
- Andrew D. Flores
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, United States
| | - Hyun G. Choi
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Rodrigo Martinez
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Moses Onyeabor
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - E. Zeynep Ayla
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, United States
| | - Amanda Godar
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Michael Machas
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, United States
| | - David R. Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
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10
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Kim HJ, Jeong H, Lee SJ. Short-Term Adaptation Modulates Anaerobic Metabolic Flux to Succinate by Activating ExuT, a Novel D-Glucose Transporter in Escherichia coli. Front Microbiol 2020; 11:27. [PMID: 32038601 PMCID: PMC6989600 DOI: 10.3389/fmicb.2020.00027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/08/2020] [Indexed: 11/18/2022] Open
Abstract
The sugar phosphotransferase system (PTS) is an essential energy-saving mechanism, particularly under anaerobic conditions. Since the PTS consumes equimolar phosphoenolpyruvate to phosphorylate each molecule of internalized glucose in the process of pyruvate generation, its absence can adversely affect the mixed acid fermentation profile and cell growth under anaerobic conditions. In this study, we report that the ΔptsG mutant cells of Escherichia coli K-12 strain exhibited inefficient glucose utilization, produced a significant amount of succinate, and exhibited a low growth rate. However, cells adapted soon after and started to grow rapidly in the same batch culture. As a result, the adapted ΔptsG cells showed the same mixed acid fermentation profiles as the wild-type cells, which was attributed to the mutation of the mlc gene, a repressor of the D-mannose PTS, another transporter for D-glucose. Similar adaptations were observed in the cells with ΔptsGΔmanX and the cells with ΔptsI that resulted in the production of a substantial amount of succinate and fast growth rate. The genome sequencing showed the presence of null mutations in the exuR gene, which encodes a modulator of exuT-encoded non-PTS sugar transporter, in adapted ΔptsGΔmanX and ΔptsI strains. Results from the RT-qPCR analysis and genetic test confirmed that the enhanced expression of ExuT, a non-PTS sugar transporter, was responsible for the uptake of D-glucose, increased succinate production, and fast growth of adapted cells. In conclusion, our study showed that the regulatory network of sugar transporters can be modulated by short-term adaptation and that downstream metabolic flux could be significantly determined by the choice of sugar transporters.
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Affiliation(s)
- Hyun Ju Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong, South Korea
| | - Haeyoung Jeong
- Gwanggyo R&D Center, Medytox Inc., Suwon, South Korea.,Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Sang Jun Lee
- Department of Systems Biotechnology, Chung-Ang University, Anseong, South Korea
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11
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Shi A, Yomano LP, York SW, Zheng H, Shanmugam KT, Ingram LO. Chromosomal mutations in Escherichia coli that improve tolerance to nonvolatile side-products from dilute acid treatment of sugarcane bagasse. Biotechnol Bioeng 2019; 117:85-95. [PMID: 31612993 DOI: 10.1002/bit.27189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/16/2019] [Accepted: 10/10/2019] [Indexed: 01/03/2023]
Abstract
Lignocellulosic biomass provides attractive nonfood carbohydrates for the production of ethanol, and dilute acid pretreatment is a biomass-independent process for access to these carbohydrates. However, this pretreatment also releases volatile and nonvolatile inhibitors of fermenting microorganisms. To identify unique gene products contributing to sensitivity/tolerance to nonvolatile inhibitors, ethanologenic Escherichia coli strain LY180 was adapted for growth in vacuum-treated sugarcane bagasse acid hydrolysate (VBHz) lacking furfural and other volatile inhibitors. A mutant, strain AQ15, obtained after approximately 500 generations of growth in VBHz, grew and fermented the sugars in a medium with 50% VBHz. Comparative genome sequence analysis of strains AQ15 and LY180 revealed 95 mutations in strain AQ15. Six of these mutations were also found in strain SL112, an independent inhibitor-tolerant derivative of strain LY180. Among these six mutations, null mutations in mdh and bacA were identified as contributing factors to VBHz tolerance in strain AQ15, based on the genetic and physiological analysis. The deletion of either gene in strain LY180 increased tolerance to VBHz from approximately 30-50% (vol/vol). Considering the location and physiological role of the two enzymes in the cell, it is likely that the two enzymes contribute to the VBHz sensitivity of ethanologenic E. coli by different mechanisms.
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Affiliation(s)
- Aiqin Shi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida.,Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida.,Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, College of Environmental and Resource Sciences, Zhejiang A & F University, Hangzhou, China
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida
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12
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Zhao C, Sinumvayo JP, Zhang Y, Li Y. Design and development of a “Y-shaped” microbial consortium capable of simultaneously utilizing biomass sugars for efficient production of butanol. Metab Eng 2019; 55:111-119. [DOI: 10.1016/j.ymben.2019.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/18/2019] [Accepted: 06/22/2019] [Indexed: 10/26/2022]
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13
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Kurgan G, Sievert C, Flores A, Schneider A, Billings T, Panyon L, Morris C, Taylor E, Kurgan L, Cartwright R, Wang X. Parallel experimental evolution reveals a novel repressive control of GalP on xylose fermentation in Escherichia coli. Biotechnol Bioeng 2019; 116:2074-2086. [PMID: 31038200 PMCID: PMC11161036 DOI: 10.1002/bit.27004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/28/2019] [Accepted: 04/25/2019] [Indexed: 12/25/2022]
Abstract
Efficient xylose utilization will facilitate microbial conversion of lignocellulosic sugar mixtures into valuable products. In Escherichia coli, xylose catabolism is controlled by carbon catabolite repression (CCR). However, in E. coli such as the succinate-producing strain KJ122 with disrupted CCR, xylose utilization is still inhibited under fermentative conditions. To probe the underlying genetic mechanisms inhibiting xylose utilization, we evolved KJ122 to enhance its xylose fermentation abilities in parallel and characterized the potential convergent genetic changes shared by multiple independently evolved strains. Whole-genome sequencing revealed that convergent mutations occurred in the galactose regulon during adaptive laboratory evolution potentially decreasing the transcriptional level or the activity of GalP, a galactose permease. We showed that deletion of galP increased xylose utilization in both KJ122 and wild-type E. coli, demonstrating a common repressive role of GalP for xylose fermentation. Concomitantly, induced expression of galP from a plasmid repressed xylose fermentation. Transcriptome analysis using RNA sequencing indicates that galP inactivation increases transcription levels of many catabolic genes for secondary sugars including xylose and arabinose. The repressive role of GalP for fermenting secondary sugars in E. coli suggests that utilization of GalP as a substitute glucose transporter is undesirable for conversion of lignocellulosic sugar mixtures.
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Affiliation(s)
- Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Christian Sievert
- School of Life Sciences, Arizona State University, Tempe, Arizona
- The Biodesign Institute, Arizona State University, Tempe, Arizona
| | - Andrew Flores
- Chemical Engineering Program, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona
| | - Aidan Schneider
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Thomas Billings
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Larry Panyon
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Chandler Morris
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Eric Taylor
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Logan Kurgan
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Reed Cartwright
- School of Life Sciences, Arizona State University, Tempe, Arizona
- The Biodesign Institute, Arizona State University, Tempe, Arizona
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, Arizona
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14
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The K296-D320 region of recombinant levansucrase BA-SacB can affect the sensitivity of Escherichia coli host to sucrose. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-019-01496-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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15
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Flores AD, Ayla EZ, Nielsen DR, Wang X. Engineering a Synthetic, Catabolically Orthogonal Coculture System for Enhanced Conversion of Lignocellulose-Derived Sugars to Ethanol. ACS Synth Biol 2019; 8:1089-1099. [PMID: 30979337 DOI: 10.1021/acssynbio.9b00007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fermentation of lignocellulosic sugar mixtures is often suboptimal due to inefficient xylose catabolism and sequential sugar utilization caused by carbon catabolite repression. Unlike in conventional applications employing a single engineered strain, the alternative development of synthetic microbial communities facilitates the execution of complex metabolic tasks by exploiting the unique community features, including modularity, division of labor, and facile tunability. A series of synthetic, catabolically orthogonal coculture systems were systematically engineered, as derived from either wild-type Escherichia coli W or ethanologenic LY180. Net catabolic activities were effectively balanced by simple tuning of the inoculum ratio between specialist strains, which enabled coutilization (98% of 100 g L-1 total sugars) of glucose-xylose mixtures (2:1 by mass) for both culture systems in simple batch fermentations. The engineered ethanologenic cocultures achieved ethanol titer (46 g L-1), productivity (488 mg L-1 h-1), and yield (∼90% of theoretical maximum), which were all significantly increased compared to LY180 monocultures.
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Affiliation(s)
- Andrew D. Flores
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, ECG 301, 501 E. Tyler Mall, Tempe, Arizona 85287, United States
| | - E. Zeynep Ayla
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, ECG 301, 501 E. Tyler Mall, Tempe, Arizona 85287, United States
| | - David R. Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, ECG 301, 501 E. Tyler Mall, Tempe, Arizona 85287, United States
| | - Xuan Wang
- School of Life Sciences, Arizona State University, 427 E. Tyler Mall, Tempe, Arizona 85287, United States
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16
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Jampatesh S, Sawisit A, Wong N, Jantama SS, Jantama K. Evaluation of inhibitory effect and feasible utilization of dilute acid-pretreated rice straws on succinate production by metabolically engineered Escherichia coli AS1600a. BIORESOURCE TECHNOLOGY 2019; 273:93-102. [PMID: 30419446 DOI: 10.1016/j.biortech.2018.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
This work demonstrated a pioneer work in the pre-treatment of rice straw by phosphoric acid (H3PO4) for succinate production. The optimized pre-treatment condition of rice straw was at 121 °C for 30 min with 2 N H3PO4. With this condition, total sugar concentration of 31.2 g/L with the highest hemicellulose saccharification yield of 94% was obtained. The physicochemical analysis of the pre-treated rice straw showed significant changes in its structure thus enhancing enzymatic saccharification. Succinate concentrations of 78.5 and 63.8 g/L were produced from hydrolysate liquor (L) and solid fraction (S) of the pre-treated rice straw respectively, with a comparable yield of 86% by E. coli AS1600a. Use of a combined L + S fraction in simultaneous saccharification and fermentation (LS + SSF) further improved succinate production at a concentration and yield of 85.6 g/L and 90% respectively. The results suggested that H3PO4 pre-treated rice straw may be utilized for economical succinate production by E. coli AS1600a.
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Affiliation(s)
- Surawee Jampatesh
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Apichai Sawisit
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Nonthaporn Wong
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Sirima Suvarnakuta Jantama
- Division of Biopharmacy, Faculty of Pharmaceutical Sciences, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand
| | - Kaemwich Jantama
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
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17
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Um J, Kim DG, Jung MY, Saratale GD, Oh MK. Metabolic engineering of Enterobacter aerogenes for 2,3-butanediol production from sugarcane bagasse hydrolysate. BIORESOURCE TECHNOLOGY 2017; 245:1567-1574. [PMID: 28596073 DOI: 10.1016/j.biortech.2017.05.166] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/25/2017] [Accepted: 05/26/2017] [Indexed: 06/07/2023]
Abstract
The pathway engineering of Enterobacter aerogenes was attempted to improve its production capability of 2,3-butanediol from lignocellulosic biomass. In the medium containing glucose and xylose mixture as carbon sources, the gene deletion of pflB improved 2,3-butanediol carbon yield by 40%, while the deletion of ptsG increased xylose consumption rate significantly, improving the productivity at 12 hr by 70%. The constructed strain, EMY-22-galP, overexpressing glucose transporter (galP) in the triple gene knockout E. aerogenes, ldhA, pflB, and ptsG, provided the highest 2,3-butanediol titer and yield at 12 hr flask cultivation. Sugarcane bagasse was pretreated with green liquor, a solution containing Na2CO3 and Na2SO3 and was hydrolyzed by enzymes. The resulting hydrolysate was used as a carbon source for 2,3-butanediol production. After 72 hr in fermentation, the yield of 0.395g/g sugar was achieved, suggesting an economic production of 2,3-butanediol was possible from lignocellulosic biomass with the metabolically engineered strain.
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Affiliation(s)
- Jaeyong Um
- Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 02841, South Korea
| | - Duck Gyun Kim
- Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 02841, South Korea
| | - Moo-Young Jung
- CJ Research Institute of Biotechnology, Suwon, Gyeonggi 16495, South Korea
| | - Ganesh D Saratale
- Department of Food Science and Biotechnology, Dongguk University, Goyang, Gyeonggi 10326, South Korea
| | - Min-Kyu Oh
- Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 02841, South Korea.
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18
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Current advances of succinate biosynthesis in metabolically engineered Escherichia coli. Biotechnol Adv 2017; 35:1040-1048. [DOI: 10.1016/j.biotechadv.2017.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 09/14/2017] [Accepted: 09/15/2017] [Indexed: 01/19/2023]
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19
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Khunnonkwao P, Jantama SS, Kanchanatawee S, Jantama K. Re-engineering Escherichia coli KJ122 to enhance the utilization of xylose and xylose/glucose mixture for efficient succinate production in mineral salt medium. Appl Microbiol Biotechnol 2017; 102:127-141. [PMID: 29079860 DOI: 10.1007/s00253-017-8580-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/05/2017] [Accepted: 10/09/2017] [Indexed: 11/30/2022]
Abstract
Escherichia coli KJ122 was previously engineered to produce high concentration and yield of succinate in mineral salt medium containing glucose and sucrose under anaerobic conditions. However, this strain does not efficiently utilize xylose. To improve the xylose uptake and utilization in the strain KJ122, xylFGH and xylE genes were individually and simultaneously deleted. E. coli KJ12201 (KJ122::ΔxylFGH) exhibited superior abilities in growth, xylose consumption, and succinate production compared to those of the parental strain KJ122. However, E. coli KJ12202 (KJ122::ΔxylE) lessened xylose consumption due to an ATP deficit for metabolizing xylose thus making succinate production from xylose not preferable. Moreover, E. coli KJ12203 (KJ122::ΔxylFGHΔxylE) exhibited an impaired growth on xylose due to lacking of xylose transporters. After performing metabolic evolution, the evolved KJ12201-14T strain exhibited a great improvement in succinate production from pure xylose with higher concentration and productivity about 18 and 21%, respectively, compared to KJ12201 strain. During fed-batch fermentation, KJ12201-14T also produced succinate from xylose at a concentration, yield, and overall productivity of 84.6 ± 0.7 g/L, 0.86 ± 0.01 g/g and 1.01 ± 0.01 g/L/h, respectively. KJ12201 and KJ12201-14T strains co-utilized glucose/xylose mixture without catabolite repression. Both strains produced succinate from glucose/xylose mixture at concentration, yield, and overall and specific productivities of about 85 g/L, 0.85 g/g, 0.70 g/L/h, and 0.44 g/gCDW/h, respectively. Based on our results, KJ12201 and KJ12201-14T strains exhibited a greater performance in succinate production from xylose containing medium than those of other published works. They would be potential strains for the economic bio-based succinate production from xylose.
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Affiliation(s)
- Panwana Khunnonkwao
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Suranaree Sub-District, Muang District, Nakhon Ratchasima, 30000, Thailand
| | - Sirima Suvarnakuta Jantama
- Division of Biopharmacy, Faculty of Pharmaceutical Sciences, Ubon Ratchathani University, Warinchamrap, Ubon Ratchathani, 34190, Thailand
| | - Sunthorn Kanchanatawee
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Suranaree Sub-District, Muang District, Nakhon Ratchasima, 30000, Thailand
| | - Kaemwich Jantama
- Metabolic Engineering Research Unit, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Suranaree Sub-District, Muang District, Nakhon Ratchasima, 30000, Thailand.
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20
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Experimental evolution reveals an effective avenue to release catabolite repression via mutations in XylR. Proc Natl Acad Sci U S A 2017; 114:7349-7354. [PMID: 28655843 DOI: 10.1073/pnas.1700345114] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microbial production of fuels and chemicals from lignocellulosic biomass provides promising biorenewable alternatives to the conventional petroleum-based products. However, heterogeneous sugar composition of lignocellulosic biomass hinders efficient microbial conversion due to carbon catabolite repression. The most abundant sugar monomers in lignocellulosic biomass materials are glucose and xylose. Although industrial Escherichia coli strains efficiently use glucose, their ability to use xylose is often repressed in the presence of glucose. Here we independently evolved three E. coli strains from the same ancestor to achieve high efficiency for xylose fermentation. Each evolved strain has a point mutation in a transcriptional activator for xylose catabolic operons, either CRP or XylR, and these mutations are demonstrated to enhance xylose fermentation by allelic replacements. Identified XylR variants (R121C and P363S) have a higher affinity to their DNA binding sites, leading to a xylose catabolic activation independent of catabolite repression control. Upon introducing these amino acid substitutions into the E. coli D-lactate producer TG114, 94% of a glucose-xylose mixture (50 g⋅L-1 each) was used in mineral salt media that led to a 50% increase in product titer after 96 h of fermentation. The two amino acid substitutions in XylR enhance xylose utilization and release glucose-induced repression in different E. coli hosts, including wild type, suggesting its potential wide application in industrial E. coli biocatalysts.
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21
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Signal peptide-dependent protein translocation pathway is crucial for the sucrose sensitivity of SacB-expressing Escherichia coli. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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22
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Brodeur G, Telotte J, Stickel JJ, Ramakrishnan S. Two-stage dilute-acid and organic-solvent lignocellulosic pretreatment for enhanced bioprocessing. BIORESOURCE TECHNOLOGY 2016; 220:621-628. [PMID: 27631703 DOI: 10.1016/j.biortech.2016.08.089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
A two stage pretreatment approach for biomass is developed in the current work in which dilute acid (DA) pretreatment is followed by a solvent based pretreatment (N-methyl morpholine N oxide - NMMO). When the combined pretreatment (DAWNT) is applied to sugarcane bagasse and corn stover, the rates of hydrolysis and overall yields (>90%) are seen to dramatically improve and under certain conditions 48h can be taken off the time of hydrolysis with the additional NMMO step to reach similar conversions. DAWNT shows a 2-fold increase in characteristic rates and also fractionates different components of biomass - DA treatment removes the hemicellulose while the remaining cellulose is broken down by enzymatic hydrolysis after NMMO treatment to simple sugars. The remaining residual solid is high purity lignin. Future work will focus on developing a full scale economic analysis of DAWNT for use in biomass fractionation.
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Affiliation(s)
- G Brodeur
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310, United States
| | - J Telotte
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310, United States
| | - J J Stickel
- National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO 80401, United States
| | - S Ramakrishnan
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310, United States.
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23
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ATP-Based Ratio Regulation of Glucose and Xylose Improved Succinate Production. PLoS One 2016; 11:e0157775. [PMID: 27315279 PMCID: PMC4912068 DOI: 10.1371/journal.pone.0157775] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/03/2016] [Indexed: 12/17/2022] Open
Abstract
We previously engineered E. coli YL104H to efficiently produce succinate from glucose. Furthermore, the present study proved that YL104H could also co-utilize xylose and glucose for succinate production. However, anaerobic succinate accumulation using xylose as the sole carbon source failed, probably because of an insufficient supply of energy. By analyzing the ATP generation under anaerobic conditions in the presence of glucose or xylose, we indicated that succinate production was affected by the intracellular ATP level, which can be simply regulated by the substrate ratio of xylose to glucose. This finding was confirmed by succinate production using an artificial mixture containing different xylose to glucose ratios. Using xylose mother liquor, a waste containing both glucose and xylose derived from xylitol production, a final succinate titer of 61.66 g/L with an overall productivity of 0.95 g/L/h was achieved, indicating that the regulation of the intracellular ATP level may be a useful and efficient strategy for succinate production and can be extended to other anaerobic processes.
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24
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Shi A, Zheng H, Yomano LP, York SW, Shanmugam KT, Ingram LO. Plasmidic Expression of nemA and yafC* Increased Resistance of Ethanologenic Escherichia coli LY180 to Nonvolatile Side Products from Dilute Acid Treatment of Sugarcane Bagasse and Artificial Hydrolysate. Appl Environ Microbiol 2016; 82:2137-2145. [PMID: 26826228 PMCID: PMC4807516 DOI: 10.1128/aem.03488-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/24/2016] [Indexed: 11/20/2022] Open
Abstract
Hydrolysate-resistant Escherichia coli SL100 was previously isolated from ethanologenic LY180 after sequential transfers in AM1 medium containing a dilute acid hydrolysate of sugarcane bagasse and was used as a source of resistance genes. Many genes that affect tolerance to furfural, the most abundant inhibitor, have been described previously. To identify genes associated with inhibitors other than furfural, plasmid clones were selected in an artificial hydrolysate that had been treated with a vacuum to remove furfural. Two new resistance genes were discovered from Sau3A1 libraries of SL100 genomic DNA: nemA (N-ethylmaleimide reductase) and a putative regulatory gene containing a mutation in the coding region, yafC*. The presence of these mutations in SL100 was confirmed by sequencing. A single mutation was found in the upstream regulatory region of nemR (nemRA operon) in SL100. This mutation increased nemA activity 20-fold over that of the parent organism (LY180) in AM1 medium without hydrolysate and increased nemA mRNA levels >200-fold. Addition of hydrolysates induced nemA expression (mRNA and activity), in agreement with transcriptional control. NemA activity was stable in cell extracts (9 h, 37°C), eliminating a role for proteinase in regulation. LY180 with a plasmid expressing nemA or yafC* was more resistant to a vacuum-treated sugarcane bagasse hydrolysate and to a vacuum-treated artificial hydrolysate than LY180 with an empty-vector control. Neither gene affected furfural tolerance. The vacuum-treated hydrolysates inhibited the reduction of N-ethylmaleimide by NemA while also serving as substrates. Expression of the nemA or yafC* plasmid in LY180 doubled the rate of ethanol production from the vacuum-treated sugarcane bagasse hydrolysate.
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Affiliation(s)
- Aiqin Shi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Huabao Zheng
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Lorraine P Yomano
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Sean W York
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Keelnatham T Shanmugam
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Lonnie O Ingram
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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