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Vavitsas K, Fabris M, Vickers CE. Terpenoid Metabolic Engineering in Photosynthetic Microorganisms. Genes (Basel) 2018; 9:E520. [PMID: 30360565 PMCID: PMC6266707 DOI: 10.3390/genes9110520] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 12/13/2022] Open
Abstract
Terpenoids are a group of natural products that have a variety of roles, both essential and non-essential, in metabolism and in biotic and abiotic interactions, as well as commercial applications such as pharmaceuticals, food additives, and chemical feedstocks. Economic viability for commercial applications is commonly not achievable by using natural source organisms or chemical synthesis. Engineered bio-production in suitable heterologous hosts is often required to achieve commercial viability. However, our poor understanding of regulatory mechanisms and other biochemical processes makes obtaining efficient conversion yields from feedstocks challenging. Moreover, production from carbon dioxide via photosynthesis would significantly increase the environmental and potentially the economic credentials of these processes by disintermediating biomass feedstocks. In this paper, we briefly review terpenoid metabolism, outline some recent advances in terpenoid metabolic engineering, and discuss why photosynthetic unicellular organisms-such as algae and cyanobacteria-might be preferred production platforms for the expression of some of the more challenging terpenoid pathways.
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Affiliation(s)
- Konstantinos Vavitsas
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia.
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia.
| | - Michele Fabris
- Climate Change Cluster, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia.
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia.
| | - Claudia E Vickers
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia.
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia.
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Englund E, Shabestary K, Hudson EP, Lindberg P. Systematic overexpression study to find target enzymes enhancing production of terpenes in Synechocystis PCC 6803, using isoprene as a model compound. Metab Eng 2018; 49:164-177. [PMID: 30025762 DOI: 10.1016/j.ymben.2018.07.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/28/2018] [Accepted: 07/08/2018] [Indexed: 11/25/2022]
Abstract
Of the two natural metabolic pathways for making terpenoids, biotechnological utilization of the mevalonate (MVA) pathway has enabled commercial production of valuable compounds, while the more recently discovered but stoichiometrically more efficient methylerythritol phosphate (MEP) pathway is underdeveloped. We conducted a study on the overexpression of each enzyme in the MEP pathway in the unicellular cyanobacterium Synechocystis sp. PCC 6803, to identify potential targets for increasing flux towards terpenoid production, using isoprene as a reporter molecule. Results showed that the enzymes Ipi, Dxs and IspD had the biggest impact on isoprene production. By combining and creating operons out of those genes, isoprene production was increased 2-fold compared to the base strain. A genome-scale model was used to identify targets upstream of the MEP pathway that could redirect flux towards terpenoids. A total of ten reactions from the Calvin-Benson-Bassham cycle, lower glycolysis and co-factor synthesis pathways were probed for their effect on isoprene synthesis by co-expressing them with the MEP enzymes, resulting in a 60% increase in production from the best strain. Lastly, we studied two isoprene synthases with the highest reported catalytic rates. Only by expressing them together with Dxs and Ipi could we get stable strains that produced 2.8 mg/g isoprene per dry cell weight, a 40-fold improvement compared to the initial strain.
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Affiliation(s)
- Elias Englund
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden; School of Biotechnology, KTH - Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Kiyan Shabestary
- School of Biotechnology, KTH - Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Elton P Hudson
- School of Biotechnology, KTH - Royal Institute of Technology, Science for Life Laboratory, Stockholm, Sweden
| | - Pia Lindberg
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
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Choi SY, Sim SJ, Choi JI, Woo HM. Identification of small droplets of photosynthetic squalene in engineered Synechococcus elongatus PCC 7942 using TEM and selective fluorescent Nile red analysis. Lett Appl Microbiol 2018. [PMID: 29527705 DOI: 10.1111/lam.12874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To identify microbial squalene that has been widely used in various industrial applications, intracellular formation of photosynthetic squalene was investigated using the previously engineered Synechococcus elongatusPCC 7942 strain. Unlike the proposed localization of squalene in the membrane bilayer, small droplets were identified in the cytoplasm of S. elongatusPCC 7942 as squalene using transmission electron microscopy analysis. Determination of the diameters of the squalene droplets with manual examination of 1016 droplets in different squalene-producing strains indicated larger squalene droplets in larger cells. Based on the observation of a sole droplet of squalene in a cyanobacterium, fluorescent Nile red was used for the selective staining of squalene. The fluorescent intensities were correlated with squalene contents determined using gas chromatography-mass spectrometry. Photosynthetic squalene was identified as a small droplet in S. elongatusPCC 7942, and this noninvasive quantitative method could be useful to promote high-throughput strain development for squalene production. SIGNIFICANCE AND IMPACT OF THE STUDY Engineering of Cyanobacteria has focused on sustainable production of squalene by converting CO2 . Before improving the photosynthetic squalene production, we characterized formation of squalene, showing small droplets in the cytoplasm instead of single granule. Based on the finding and the analysis, this study has provided valuable evidences how further metabolic engineering strategies should apply to enhance the production yield.
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Affiliation(s)
- S Y Choi
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), Jangan-gu, Suwon, Korea.,Institute of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), Jangan-gu, Suwon, Korea
| | - S J Sim
- Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul, Korea
| | - J-I Choi
- Department of Biotechnology and Bioengineering, Chonnam National University, Buk-gu, Gwangju, Korea
| | - H M Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), Jangan-gu, Suwon, Korea
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Badshah SL, Ullah A, Ahmad N, Almarhoon ZM, Mabkhot Y. Increasing the Strength and Production of Artemisinin and Its Derivatives. Molecules 2018; 23:E100. [PMID: 29301383 PMCID: PMC6017432 DOI: 10.3390/molecules23010100] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/19/2017] [Accepted: 12/28/2017] [Indexed: 12/04/2022] Open
Abstract
Artemisinin is a natural sesquiterpene lactone obtained from the Artemisia annua herb. It is widely used for the treatment of malaria. In this article, we have reviewed the role of artemisinin in controlling malaria, spread of resistance to artemisinin and the different methods used for its large scale production. The highest amount of artemisinin gene expression in tobacco leaf chloroplast leads to the production of 0.8 mg/g of the dry weight of the plant. This will revolutionize the treatment and control of malaria in third world countries. Furthermore, the generations of novel derivatives of artemisinin- and trioxane ring structure-inspired compounds are important for the treatment of malaria caused by resistant plasmodial species. Synthetic endoperoxide-like artefenomel and its derivatives are crucial for the control of malaria and such synthetic compounds should be further explored.
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Affiliation(s)
- Syed Lal Badshah
- Department of Chemistry, Islamia College University Peshawar, Peshawar 25120, Pakistan.
| | - Asad Ullah
- Department of Chemistry, Islamia College University Peshawar, Peshawar 25120, Pakistan.
| | - Nasir Ahmad
- Department of Chemistry, Islamia College University Peshawar, Peshawar 25120, Pakistan.
| | - Zainab M Almarhoon
- Department of Chemistry, College of Sciences, King Saud University, Riyadh 11451, Saudi Arabia.
| | - Yahia Mabkhot
- Department of Chemistry, College of Sciences, King Saud University, Riyadh 11451, Saudi Arabia.
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Tailored carbon partitioning for phototrophic production of (E)-α-bisabolene from the green microalga Chlamydomonas reinhardtii. Metab Eng 2018; 45:211-222. [DOI: 10.1016/j.ymben.2017.12.010] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 11/27/2017] [Accepted: 12/11/2017] [Indexed: 12/20/2022]
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Ni J, Tao F, Xu P, Yang C. Engineering Cyanobacteria for Photosynthetic Production of C3 Platform Chemicals and Terpenoids from CO 2. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:239-259. [PMID: 30091098 DOI: 10.1007/978-981-13-0854-3_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Recent years have witnessed a rising demand for bioproduced chemicals owing to restricted availability of petrochemical resources and increasing environmental concerns. Extensive efforts have been invested in the metabolic engineering of microorganisms for biosynthesis of chemicals and fuels. Among these, direct conversion of CO2 to chemicals by photoautotrophic microorganism cyanobacteria represents a green route with incredibly potent. Cyanobacteria have been engineered for the production of numerous biofuels and chemicals, such as 2,3-butanediol, fatty acids, isobutyraldehyde, and n-butanol. Under the current condition, it might be initially wiser to produce chemicals with higher value or higher yield. Photosynthetic production of C3 platform chemicals could withdraw carbon close to fixation to maximize the pool of available carbon, thus achieving the strong production rates. Photosynthetic production of terpenoids is another good choice due to the higher value of these compounds. Here, we review recent advances in generating C3 chemicals and valuable terpenoids from cyanobacteria.
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Affiliation(s)
- Jun Ni
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Fei Tao
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Chen Yang
- CAS-Key Laboratory of Synthetic Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
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Loeschcke A, Dienst D, Wewer V, Hage-Hülsmann J, Dietsch M, Kranz-Finger S, Hüren V, Metzger S, Urlacher VB, Gigolashvili T, Kopriva S, Axmann IM, Drepper T, Jaeger KE. The photosynthetic bacteria Rhodobacter capsulatus and Synechocystis sp. PCC 6803 as new hosts for cyclic plant triterpene biosynthesis. PLoS One 2017; 12:e0189816. [PMID: 29281679 PMCID: PMC5744966 DOI: 10.1371/journal.pone.0189816] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/01/2017] [Indexed: 11/18/2022] Open
Abstract
Cyclic triterpenes constitute one of the most diverse groups of plant natural products. Besides the intriguing biochemistry of their biosynthetic pathways, plant triterpenes exhibit versatile bioactivities, including antimicrobial effects against plant and human pathogens. While prokaryotes have been extensively used for the heterologous production of other classes of terpenes, the synthesis of cyclic triterpenes, which inherently includes the two-step catalytic formation of the universal linear precursor 2,3-oxidosqualene, is still a major challenge. We thus explored the suitability of the metabolically versatile photosynthetic α-proteobacterium Rhodobacter capsulatus SB1003 and cyanobacterium Synechocystis sp. PCC 6803 as alternative hosts for biosynthesis of cyclic plant triterpenes. Therefore, 2,3-oxidosqualene production was implemented and subsequently combined with different cyclization reactions catalyzed by the representative oxidosqualene cyclases CAS1 (cycloartenol synthase), LUP1 (lupeol synthase), THAS1 (thalianol synthase) and MRN1 (marneral synthase) derived from model plant Arabidopsis thaliana. While successful accumulation of 2,3-oxidosqualene could be detected by LC-MS analysis in both hosts, cyclase expression resulted in differential production profiles. CAS1 catalyzed conversion to only cycloartenol, but expression of LUP1 yielded lupeol and a triterpenoid matching an oxidation product of lupeol, in both hosts. In contrast, THAS1 expression did not lead to cyclic product formation in either host, whereas MRN1-dependent production of marnerol and hydroxymarnerol was observed in Synechocystis but not in R. capsulatus. Our findings thus indicate that 2,3-oxidosqualene cyclization in heterologous phototrophic bacteria is basically feasible but efficient conversion depends on both the respective cyclase enzyme and individual host properties. Therefore, photosynthetic α-proteo- and cyanobacteria are promising alternative candidates for providing new bacterial access to the broad class of triterpenes for biotechnological applications.
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Affiliation(s)
- Anita Loeschcke
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
| | - Dennis Dienst
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vera Wewer
- Cluster of Excellence on Plant Sciences (CEPLAS)
- MS Platform, Department of Biology, University of Cologne, Cologne, Germany
| | - Jennifer Hage-Hülsmann
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
| | - Maximilian Dietsch
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sarah Kranz-Finger
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute of Biochemistry II, Department of Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vanessa Hüren
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sabine Metzger
- Cluster of Excellence on Plant Sciences (CEPLAS)
- MS Platform, Department of Biology, University of Cologne, Cologne, Germany
| | - Vlada B. Urlacher
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute of Biochemistry II, Department of Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tamara Gigolashvili
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Botanical Institute, University of Cologne, Cologne, Germany
| | - Stanislav Kopriva
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Botanical Institute, University of Cologne, Cologne, Germany
| | - Ilka M. Axmann
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail: (IMA); (TD)
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
- * E-mail: (IMA); (TD)
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute of Bio- and Geosciences (IBG-1), Forschungszentrum Jülich, Jülich, Germany
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58
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Lee HJ, Lee J, Lee SM, Um Y, Kim Y, Sim SJ, Choi JI, Woo HM. Direct Conversion of CO 2 to α-Farnesene Using Metabolically Engineered Synechococcus elongatus PCC 7942. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:10424-10428. [PMID: 29068210 DOI: 10.1021/acs.jafc.7b03625] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Direct conversion of carbon dioxide (CO2) to value-added chemicals by engineering of cyanobacteria has received attention as a sustainable strategy in food and chemical industries. Herein, Synechococcus elongatus PCC 7942, a model cyanobacterium, was engineered to produce α-farnesene from CO2. As a result of the lack of farnesene synthase (FS) activity in the wild-type cyanobacterium, we metabolically engineered S. elongatus PCC 7942 to express heterologous FS from either Norway spruce or apple fruit, resulting in detectable peaks of α-farnesene. To enhance α-farnesene production, an optimized methylerythritol phosphate (MEP) pathway was introduced in the farnesene-producing strain to supply farnesyl diphosphate. Subsequent cyanobacterial culture with a dodecane overlay resulted in photosynthetic production of α-farnesene (4.6 ± 0.4 mg/L in 7 days) from CO2. To the best of our knowledge, this is the first report of the photosynthetic production of α-farnesene from CO2 in the unicellular cyanobacterium S. elongatus PCC 7942.
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Affiliation(s)
| | - Jiwon Lee
- Clean Energy Research Center, Korea Institute of Science and Technology , Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, 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
| | - Yunje Kim
- Clean Energy Research Center, Korea Institute of Science and Technology , Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Sang Jun Sim
- Department of Chemical and Biological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jong-Il Choi
- Department of Biotechnology and Bioengineering, Chonnam National University , 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
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Choi SY, Wang JY, Kwak HS, Lee SM, Um Y, Kim Y, Sim SJ, Choi JI, Woo HM. Improvement of Squalene Production from CO 2 in Synechococcus elongatus PCC 7942 by Metabolic Engineering and Scalable Production in a Photobioreactor. ACS Synth Biol 2017; 6:1289-1295. [PMID: 28365988 DOI: 10.1021/acssynbio.7b00083] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The push-and-pull strategy for metabolic engineering was successfully demonstrated in Synechococcus elongatus PCC 7942, a model photosynthetic bacterium, to produce squalene from CO2. Squalene synthase (SQS) was fused to either a key enzyme (farnesyl diphosphate synthase) of the methylerythritol phosphate pathway or the β-subunit of phycocyanin (CpcB1). Engineered cyanobacteria with expression of a fusion CpcB1-SQS protein showed a squalene production level (7.16 ± 0.05 mg/L/OD730) that was increased by 1.8-fold compared to that of the control strain expressing SQS alone. To increase squalene production further, the gene dosage for CpcB1·SQS protein expression was increased and the fusion protein was expressed under a strong promoter, yielding 11.98 ± 0.49 mg/L/OD730 of squalene, representing a 3.1-fold increase compared to the control. Subsequently, the best squalene producer was cultivated in a scalable photobioreactor (6 L) with light optimization, which produced 7.08 ± 0.5 mg/L/OD730 squalene (equivalent to 79.2 mg per g dry cell weight). Further optimization for photobioprocessing and strain development will promote the construction of a solar-to-chemical platform.
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Affiliation(s)
- Sun Young Choi
- Clean
Energy Research Center, Korea Institute of Science and Technology, Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Jin-Young Wang
- Clean
Energy Research Center, Korea Institute of Science and Technology, Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | | | - Sun-Mi Lee
- Clean
Energy Research Center, Korea Institute of Science and Technology, Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Youngsoon Um
- Clean
Energy Research Center, Korea Institute of Science and Technology, Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Yunje Kim
- Clean
Energy Research Center, Korea Institute of Science and Technology, Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, 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
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Kim WJ, Lee SM, Um Y, Sim SJ, Woo HM. Development of SyneBrick Vectors As a Synthetic Biology Platform for Gene Expression in Synechococcus elongatus PCC 7942. FRONTIERS IN PLANT SCIENCE 2017; 8:293. [PMID: 28303150 PMCID: PMC5332412 DOI: 10.3389/fpls.2017.00293] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/17/2017] [Indexed: 05/20/2023]
Abstract
Cyanobacteria are oxygenic photosynthetic prokaryotes that are able to assimilate CO2 using solar energy and water. Metabolic engineering of cyanobacteria has suggested the possibility of direct CO2 conversion to value-added chemicals. However, engineering of cyanobacteria has been limited due to the lack of various genetic tools for expression and control of multiple genes to reconstruct metabolic pathways for biochemicals from CO2. Thus, we developed SyneBrick vectors as a synthetic biology platform for gene expression in Synechococcus elongatus PCC 7942 as a model cyanobacterium. The SyneBrick chromosomal integration vectors provide three inducible expression systems to control gene expression and three neutral sites for chromosomal integrations. Using a SyneBrick vector, LacI-regulated gene expression led to 24-fold induction of the eYFP reporter gene with 1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG) inducer in S. elongatus PCC 7942 under 5% (v/v) CO2. TetR-regulated gene expression led to 19-fold induction of the GFP gene when 100 nM anhydrotetracycline (aTc) inducer was used. Gene expression decreased after 48 h due to degradation of aTc under light. T7 RNA polymerase-based gene expression resulted in efficient expression with a lower IPTG concentration than a previously developed pTrc promoter. A library of T7 promoters can be used for tunable gene expression. In summary, SyneBrick vectors were developed as a synthetic biology platform for gene expression in S. elongatus PCC 7942. These results will accelerate metabolic engineering of biosolar cell factories through expressing and controlling multiple genes of interest.
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Affiliation(s)
- Wook Jin Kim
- Clean Energy Research Center, Korea Institute of Science and TechnologySeoul, South Korea
- Green School (Graduate School of Energy and Environment), Korea UniversitySeoul, South Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and TechnologySeoul, South Korea
- Green School (Graduate School of Energy and Environment), Korea UniversitySeoul, South Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and TechnologySeoul, South Korea
| | - Sang Jun Sim
- Green School (Graduate School of Energy and Environment), Korea UniversitySeoul, South Korea
- Department of Chemical and Biological Engineering, Korea UniversitySeoul, South Korea
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan UniversitySuwon, South Korea
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Peng B, Plan MR, Carpenter A, Nielsen LK, Vickers CE. Coupling gene regulatory patterns to bioprocess conditions to optimize synthetic metabolic modules for improved sesquiterpene production in yeast. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:43. [PMID: 28239415 PMCID: PMC5320780 DOI: 10.1186/s13068-017-0728-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/09/2017] [Indexed: 05/23/2023]
Abstract
BACKGROUND Assembly of heterologous metabolic pathways is commonly required to generate microbial cell factories for industrial production of both commodity chemicals (including biofuels) and high-value chemicals. Promoter-mediated transcriptional regulation coordinates the expression of the individual components of these heterologous pathways. Expression patterns vary during culture as conditions change, and this can influence yeast physiology and productivity in both positive and negative ways. Well-characterized strategies are required for matching transcriptional regulation with desired output across changing culture conditions. RESULTS Here, constitutive and inducible regulatory mechanisms were examined to optimize synthetic isoprenoid metabolic pathway modules for production of trans-nerolidol, an acyclic sesquiterpene alcohol, in yeast. The choice of regulatory system significantly affected physiological features (growth and productivity) over batch cultivation. Use of constitutive promoters resulted in poor growth during the exponential phase. Delaying expression of the assembled metabolic modules using the copper-inducible CUP1 promoter resulted in a 1.6-fold increase in the exponential-phase growth rate and a twofold increase in productivity in the post-exponential phase. However, repeated use of the CUP1 promoter in multiple expression cassettes resulted in genetic instability. A diauxie-inducible expression system, based on an engineered GAL regulatory circuit and a set of four different GAL promoters, was characterized and employed to assemble nerolidol synthetic metabolic modules. Nerolidol production was further improved by 60% to 392 mg L-1 using this approach. Various carbon source systems were investigated in batch/fed-batch cultivation to regulate induction through the GAL system; final nerolidol titres of 4-5.5 g L-1 were achieved, depending on the conditions. CONCLUSION Direct comparison of different transcriptional regulatory mechanisms clearly demonstrated that coupling the output strength to the fermentation stage is important to optimize the growth fitness and overall productivities of engineered cells in industrially relevant processes. Applying different well-characterized promoters with the same induction behaviour mitigates against the risks of homologous sequence-mediated genetic instability. Using these approaches, we significantly improved sesquiterpene production in yeast.
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Affiliation(s)
- Bingyin Peng
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Manuel R. Plan
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD 4072 Australia
- Metabolomics Australia (Queensland Node), The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Alexander Carpenter
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Lars K. Nielsen
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Claudia E. Vickers
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD 4072 Australia
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Lee HJ, Choi J, Lee SM, Um Y, Sim SJ, Kim Y, Woo HM. Photosynthetic CO 2 Conversion to Fatty Acid Ethyl Esters (FAEEs) Using Engineered Cyanobacteria. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:1087-1092. [PMID: 28128561 DOI: 10.1021/acs.jafc.7b00002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Metabolic engineering of cyanobacteria has received attention as a sustainable strategy to convert carbon dioxide to fatty acid-derived chemicals that are widely used in the food and chemical industries. Herein, Synechococcus elongatus PCC 7942, a model cyanobacterium, was engineered for the first time to produce fatty acid ethyl esters (FAEEs) from CO2. Due to the lack of an endogenous ethanol production pathway and wax ester synthase (AftA) activity in the wild-type cyanobacterium, we metabolically engineered S. elongatus PCC 7942 by expressing heterologous AftA and introducing the ethanol pathway, resulting in detectable peaks of FAEEs. To enhance FAEE production, a heterologous phosphoketolase pathway was introduced in the FAEE-producing strain to supply acetyl-CoA. Subsequent optimization of the cyanobacterial culture with a hexadecane overlay resulted in engineered S. elongatus PCC 7942 that produced photosynthetic FAEEs (10.0 ± 0.7 mg/L/OD730) from CO2. This paper is the first report of photosynthetic production of FAEEs from CO2 in cyanobacteria.
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Affiliation(s)
- Hyun Jeong Lee
- Clean Energy Research Center, Korea Institute of Science and Technology , Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Jaeyeon Choi
- Clean Energy Research Center, Korea Institute of Science and Technology , Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, 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
| | - Sang Jun Sim
- Department of Chemical and Biological Engineering, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Yunje Kim
- Clean Energy Research Center, Korea Institute of Science and Technology , Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 02792, 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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Woo HM. Solar-to-chemical and solar-to-fuel production from CO 2 by metabolically engineered microorganisms. Curr Opin Biotechnol 2017; 45:1-7. [PMID: 28088091 DOI: 10.1016/j.copbio.2016.11.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/16/2016] [Accepted: 11/23/2016] [Indexed: 01/01/2023]
Abstract
Recent development of carbon capture utilization (CCU) for reduction of greenhouse gas emission are reviewed. In the case of CO2 utilization, I describe development of solar-to-chemical and solar-to-fuel technology that refers to the use of solar energy to convert CO2 to desired chemicals and fuels. Photoautotrophic cyanobacterial platforms have been extensively developed on this principle, producing a diverse range of alcohols, organic acids, and isoprenoids directly from CO2. Recent breakthroughs in the metabolic engineering of cyanobacteria were reviewed. In addition, adoption of the light harvesting mechanisms from nature, photovoltaics-derived water splitting technologies have recently been integrated with microbial biotechnology to produce desired chemicals. Studies on the integration of electrode material with next-generation microbes are showcased for alternative solar-to-chemical and solar-to-fuel platforms.
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Affiliation(s)
- 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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