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Abdelaal AS, Jawed K, Yazdani SS. CRISPR/Cas9-mediated engineering of Escherichia coli for n-butanol production from xylose in defined medium. J Ind Microbiol Biotechnol 2019; 46:965-975. [PMID: 30982114 DOI: 10.1007/s10295-019-02180-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 04/09/2019] [Indexed: 01/14/2023]
Abstract
Butanol production from agricultural residues is the most promising alternative for fossil fuels. To reach the economic viability of biobutanol production, both glucose and xylose should be utilized and converted into butanol. Here, we engineered a dual-operon-based synthetic pathway in the genome of E. coli MG1655 to produce n-butanol using CRISPR/Cas9 technology. Further deletion of competing pathway followed by fed-batch cultivation of the engineered strain in a bioreactor with glucose-containing complex medium yielded 5.4 g/L n-butanol along with pyruvate as major co-product, indicating a redox imbalance. To ferment xylose into butanol in redox-balanced manner, we selected SSK42, an ethanologenic E. coli strain engineered and evolved in our laboratory to produce ethanol from xylose, for integrating synthetic butanol cassette in its genome via CRISPR/Cas9 after deleting the gene responsible for endogenous ethanol production. The engineered plasmid- and marker-free strain, ASA02, produced 4.32 g/L butanol in fed-batch fermentation in completely defined AM1-xylose medium.
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Affiliation(s)
- Ali Samy Abdelaal
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Department of Genetics, Faculty of Agriculture, Damietta University, Damietta, Egypt
| | - Kamran Jawed
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
- DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
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52
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Nitta K, Laviña WA, Pontrelli S, Liao JC, Putri SP, Fukusaki E. Metabolome analysis revealed the knockout of glyoxylate shunt as an effective strategy for improvement of 1-butanol production in transgenic Escherichia coli. J Biosci Bioeng 2019; 127:301-308. [DOI: 10.1016/j.jbiosc.2018.08.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 10/28/2022]
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53
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Nusantara Putra FJ, Putri SP, Fukusaki E. Metabolomics-based profiling of three terminal alkene-producing Jeotgalicoccus spp. during different growth phase. J Biosci Bioeng 2019; 127:52-58. [DOI: 10.1016/j.jbiosc.2018.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/13/2018] [Accepted: 06/19/2018] [Indexed: 10/28/2022]
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54
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Hollywood KA, Schmidt K, Takano E, Breitling R. Metabolomics tools for the synthetic biology of natural products. Curr Opin Biotechnol 2018; 54:114-120. [DOI: 10.1016/j.copbio.2018.02.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/22/2018] [Accepted: 02/27/2018] [Indexed: 12/15/2022]
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55
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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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56
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Becker J, Wittmann C. From systems biology to metabolically engineered cells — an omics perspective on the development of industrial microbes. Curr Opin Microbiol 2018; 45:180-188. [DOI: 10.1016/j.mib.2018.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/06/2018] [Accepted: 06/08/2018] [Indexed: 10/28/2022]
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Döring V, Darii E, Yishai O, Bar-Even A, Bouzon M. Implementation of a Reductive Route of One-Carbon Assimilation in Escherichia coli through Directed Evolution. ACS Synth Biol 2018; 7:2029-2036. [PMID: 30106273 DOI: 10.1021/acssynbio.8b00167] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Endowing biotechnological platform organisms with new carbon assimilation pathways is a key challenge for industrial biotechnology. Here we report progress toward the construction of formatotrophic Escherichia coli strains. Glycine and serine, universal precursors of one-carbon compounds oxidized during heterotrophic growth, are produced from formate and CO2 through a reductive route. An adaptive evolution strategy was applied to optimize the enzymatic steps of this route in appropriate selection strains. Metabolic labeling experiments with 13C-formate confirm the redirected carbon-flow. These results demonstrate the high plasticity of the central carbon metabolism of E. coli and the applicative potential of directed evolution for implementing synthetic pathways in microorganisms.
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Affiliation(s)
- Volker Döring
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France
| | - Ekaterina Darii
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France
| | - Oren Yishai
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Arren Bar-Even
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Madeleine Bouzon
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91057 Evry, France
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58
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Pontrelli S, Fricke RCB, Sakurai SSM, Putri SP, Fitz-Gibbon S, Chung M, Wu HY, Chen YJ, Pellegrini M, Fukusaki E, Liao JC. Directed strain evolution restructures metabolism for 1-butanol production in minimal media. Metab Eng 2018; 49:153-163. [PMID: 30107263 DOI: 10.1016/j.ymben.2018.08.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 06/30/2018] [Accepted: 08/10/2018] [Indexed: 01/02/2023]
Abstract
Engineering a microbial strain for production sometimes entails metabolic modifications that impair essential physiological processes for growth or production. Restoring these functions may require amending a variety of non-obvious physiological networks, and thus, rational design strategies may not be practical. Here we demonstrate that growth and production may be restored by evolution that repairs impaired metabolic function. Furthermore, we use genomics, metabolomics and proteomics to identify several underlying mutations and metabolic perturbations that allow metabolism to repair. Previously, high titers of butanol production were achieved by Escherichia coli using a growth-coupled, modified Clostridial CoA-dependent pathway after all native fermentative pathways were deleted. However, production was only observed in rich media. Native metabolic function of the host was unable to support growth and production in minimal media. We use directed cell evolution to repair this phenotype and observed improved growth, titers and butanol yields. We found a mutation in pcnB which resulted in decreased plasmid copy numbers and pathway enzymes to balance resource utilization. Increased protein abundance was measured for biosynthetic pathways, glycolytic enzymes have increased activity, and adenosyl energy charge was increased. We also found mutations in the ArcAB two-component system and integration host factor (IHF) that tune redox metabolism to alter byproduct formation. These results demonstrate that directed strain evolution can enable systematic adaptations to repair metabolic function and enhance microbial production. Furthermore, these results demonstrate the versatile repair capabilities of cell metabolism and highlight important aspects of cell physiology that are required for production in minimal media.
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Affiliation(s)
- Sammy Pontrelli
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles (UCLA), United States
| | - Riley C B Fricke
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles (UCLA), United States
| | | | - Sastia Prama Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Japan
| | - Sorel Fitz-Gibbon
- Institute of Genomics and Proteomics, University of California, Los Angeles, United States
| | - Matthew Chung
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles (UCLA), United States
| | - Hsin-Yi Wu
- Instrumentation Center, National Taiwan University, Taipei, Taiwan
| | - Yu-Ju Chen
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Matteo Pellegrini
- Institute of Genomics and Proteomics, University of California, Los Angeles, United States; Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, United States
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Japan
| | - James C Liao
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
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Metabolomics approach to reduce the Crabtree effect in continuous culture of Saccharomyces cerevisiae. J Biosci Bioeng 2018; 126:183-188. [DOI: 10.1016/j.jbiosc.2018.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 12/24/2017] [Accepted: 02/12/2018] [Indexed: 11/21/2022]
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60
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Putri SP, Nakayama Y, Shen C, Noguchi S, Nitta K, Bamba T, Pontrelli S, Liao J, Fukusaki E. Identifying metabolic elements that contribute to productivity of 1-propanol bioproduction using metabolomic analysis. Metabolomics 2018; 14:96. [PMID: 30830363 DOI: 10.1007/s11306-018-1386-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
INTRODUCTION Previously constructed Escherichia coli strains that produce 1-propanol use the native threonine pathway, or a heterologous citramalate pathway. However, based on the energy and cofactor requirements of each pathway, a combination of the two pathways produces synergistic effects that increase the theoretical maximum yield with a simultaneous unexplained increase in productivity. OBJECTIVE Identification of key factors that contribute to synergistic effect leading to 1-propanol yield and productivity improvement in E. coli with native threonine pathway and heterologous citramalate pathway. METHOD A combination of snapshot metabolomic profiling and dynamic metabolic turnover analysis were used to identify system-wide perturbations that contribute to the productivity improvement. RESULT AND CONCLUSION In the presence of both pathways, increased glucose consumption and elevated levels of glycolytic intermediates are attributed to an elevated phosphoenolpyruvate (PEP)/pyruvate ratio that is known to increase the function of the native phosphotransferase. Turnover analysis of nitrogen containing byproducts reveals that ammonia assimilation, required for the threonine pathway, is streamlined when provided with an NAD(P)H surplus in the presence of the citramalate pathway. Our study illustrates the application of metabolomics in identification of factors that alter cellular physiology for improvement of 1-propanol bioproduction.
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Affiliation(s)
- Sastia Prama Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Yasumune Nakayama
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Department of Applied Microbial Technology, Sojo University, 4-22-1 Ikeda, Kumamoto, 860-0082, Japan
| | - Claire Shen
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 300, Taiwan, Republic of China
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - Shingo Noguchi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Drug Metabolism & Pharmacokinetics Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., Shinagawa R&D Center, 1-2-58, Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Katsuaki Nitta
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takeshi Bamba
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka, 812-8285, Japan
| | - Sammy Pontrelli
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - James Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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61
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Fathima AM, Chuang D, Laviña WA, Liao J, Putri SP, Fukusaki E. Iterative cycle of widely targeted metabolic profiling for the improvement of 1-butanol titer and productivity in Synechococcus elongatus. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:188. [PMID: 30002728 PMCID: PMC6036673 DOI: 10.1186/s13068-018-1187-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/25/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND Metabolomics is the comprehensive study of metabolites that can demonstrate the downstream effects of gene and protein regulation, arguably representing the closest correlation with phenotypic features. Hence, metabolomics-driven approach offers an effective way to facilitate strain improvement. Previously, targeted metabolomics on the 1-butanol-producing cyanobacterial strain Synechococcus elongatus BUOHSE has revealed the reduction step from butanoyl-CoA to butanal, catalyzed by CoA-acylating propionaldehyde dehydrogenase (PduP), as a rate-limiting step in the CoA-dependent pathway. Moreover, an increase in acetyl-CoA synthesis rate was also observed in this strain, by which the increased rate of release of CoA from butanoyl-CoA was used to enhance formation of acetyl-CoA to feed into the pathway. RESULTS In the present study, a new strain (DC7) with an improved activity of PduP enzyme, was constructed using BUOHSE as the background strain. DC7 showed a 33% increase in 1-butanol production compared to BUOHSE. For a deeper understanding of the metabolic state of DC7, widely targeted metabolomics approach using ion-pair reversed-phase LC/MS was performed. Results showed a decreased level of butanoyl-CoA and an increased level of acetyl-CoA in DC7 compared to BUOHSE. This served as an indication that the previous bottleneck has been solved and free CoA regeneration increased upon the improvement of the PduP enzyme. In order to utilize the enhanced levels of acetyl-CoA in DC7 for 1-butanol production, overexpression of acetyl-CoA carboxylase (ACCase) in DC7 was performed by inserting the gene encoding an ACCase subunit from Yarrowia lipolytica into the aldA site. The resulting strain, named DC11, was able to reach a production titer of 418.7 mg/L in 6 days, compared to DC7 that approached a similar titer in 12 days. A maximum productivity of 117 mg/L/day was achieved between days 4 and 5 in DC11. CONCLUSIONS In this study, the iterative cycle of genetic modification based on insights from metabolomics successfully resulted in the highest reported 1-butanol productivity for engineered Synechococcus elongatus PCC 7942.
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Affiliation(s)
- Artnice Mega Fathima
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Derrick Chuang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095 USA
| | - Walter Alvarez Laviña
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan
- Microbiology Division, Institute of Biological Sciences, University of the Philippines Los, Banos, 4031 Philippines
| | - James Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095 USA
| | - Sastia Prama Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan
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62
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Steps towards 'drop-in' biofuels: focusing on metabolic pathways. Curr Opin Biotechnol 2017; 53:26-32. [PMID: 29207330 DOI: 10.1016/j.copbio.2017.10.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 12/20/2022]
Abstract
The past decade has witnessed rapid advance in microbial production of 'drop-in' biofuels from renewable resources. Various biosynthetic pathways have been constructed to produce biofuels with diverse structures, and multiple metabolic engineering strategies have been developed to increase biofuel titers, yields, productivities and system robustness. In this review, we intend to give a brief but comprehensive overview of the most recent progresses on four essential pathways leading to 'drop-in' biofuel production, with an emphasis on the metabolic pathway efficiencies and biofuel structures. Furthermore, we also provide an insightful discussion on optimization strategies to improve the robustness of the microbial platforms for biofuel production.
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64
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A systematically chromosomally engineered Escherichia coli efficiently produces butanol. Metab Eng 2017; 44:284-292. [PMID: 29102594 DOI: 10.1016/j.ymben.2017.10.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 11/22/2022]
Abstract
Biotechnological production of butanol in heterologous hosts has recently attracted many interests. Of the heterologous hosts investigated to date, engineered Escherichia coli has shown a superior butanol yield than the natural butanol-producing clostridial strains. However, all reported butanol-producing E. coli strains contain vectors and inducible promoters, which means antibiotics and inducers are required in the fermentation. The aim of this study was to develop a completely chromosomally engineered E. coli strain capable of producing butanol efficiently in the absence of vectors, antibiotics, and inducers. The challenges are the expression strength of chromosomally engineered genes under constitutive promoters is much weaker than the vector engineered genes under inducible promoters. To address these challenges, the butanol pathway was engineered into the chromosome in the first place, then the host and the butanol pathway was iteratively engineered through rational and non-rational strategies to develop an efficient butanol producer where the heterologous butanol pathway fits the host well. Finally, a systematically chromosomally engineered E. coli strain EB243, in which 33 native genes were deleted and 5 heterologous genes were introduced, was developed. Strain EB243 could produce 20g/L butanol with a yield of 34% (w/w, 83% of theoretical yield) in batch fermentation without any antibiotics and inducers, thus showed great potential for industrial application. This work also demonstrated a procedure on how to integrate the existing knowledge to engineer a strain with industrial application potential.
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65
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Nitta K, Laviña WA, Pontrelli S, Liao JC, Putri SP, Fukusaki E. Orthogonal partial least squares/projections to latent structures regression-based metabolomics approach for identification of gene targets for improvement of 1-butanol production in Escherichia coli. J Biosci Bioeng 2017; 124:498-505. [PMID: 28669528 DOI: 10.1016/j.jbiosc.2017.05.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/10/2017] [Accepted: 05/24/2017] [Indexed: 12/13/2022]
Abstract
Metabolomics is the comprehensive analysis of metabolites in biological systems that uses multivariate analyses such as principal component analysis (PCA) or partial least squares/projections to latent structures regression (PLSR) to understand the metabolome state and extract important information from biological systems. In this study, orthogonal PLSR (OPLSR) model-based metabolomics approach was applied to 1-butanol producing Escherichia coli to facilitate in strain improvement strategies. Here, metabolite data obtained by liquid chromatography/mass spectrometry (LC/MS) was used to construct an OPLSR model to correlate metabolite changes with 1-butanol production and rationally identify gene targets for strain improvement. Using this approach, acetyl-CoA was determined as the rate-limiting step of the pathway while free CoA was found to be insufficient for 1-butanol production. By resolving the problems addressed by the OPLSR model, higher 1-butanol productivity was achieved. In this study, the usefulness of OPLSR-based metabolomics approach for understanding the whole metabolome state and determining the most relevant metabolites was demonstrated. Moreover, it was able to provide valuable insights for selection of rational gene targets for strain improvement.
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Affiliation(s)
- Katsuaki Nitta
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Walter A Laviña
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Sammy Pontrelli
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA.
| | - James C Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA.
| | - Sastia P Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Zhao C, Zhao Q, Li Y, Zhang Y. Engineering redox homeostasis to develop efficient alcohol-producing microbial cell factories. Microb Cell Fact 2017; 16:115. [PMID: 28646866 PMCID: PMC5483285 DOI: 10.1186/s12934-017-0728-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/16/2017] [Indexed: 12/11/2022] Open
Abstract
The biosynthetic pathways of most alcohols are linked to intracellular redox homeostasis, which is crucial for life. This crucial balance is primarily controlled by the generation of reducing equivalents, as well as the (reduction)-oxidation metabolic cycle and the thiol redox homeostasis system. As a main oxidation pathway of reducing equivalents, the biosynthesis of most alcohols includes redox reactions, which are dependent on cofactors such as NADH or NADPH. Thus, when engineering alcohol-producing strains, the availability of cofactors and redox homeostasis must be considered. In this review, recent advances on the engineering of cellular redox homeostasis systems to accelerate alcohol biosynthesis are summarized. Recent approaches include improving cofactor availability, manipulating the affinity of redox enzymes to specific cofactors, as well as globally controlling redox reactions, indicating the power of these approaches, and opening a path towards improving the production of a number of different industrially-relevant alcohols in the near future.
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Affiliation(s)
- Chunhua Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Qiuwei Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
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