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Liu X, Tang K, Hu J. Application of Cyanobacteria as Chassis Cells in Synthetic Biology. Microorganisms 2024; 12:1375. [PMID: 39065143 PMCID: PMC11278661 DOI: 10.3390/microorganisms12071375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
Synthetic biology is an exciting new area of research that combines science and engineering to design and build new biological functions and systems. Predictably, with the development of synthetic biology, more efficient and economical photosynthetic microalgae chassis will be successfully constructed, making it possible to break through laboratory research into large-scale industrial applications. The synthesis of a range of biochemicals has been demonstrated in cyanobacteria; however, low product titers are the biggest barrier to the commercialization of cyanobacterial biotechnology. This review summarizes the applied improvement strategies from the perspectives of cyanobacteria chassis cells and synthetic biology. The harvest advantages of cyanobacterial products and the latest progress in improving production strategies are discussed according to the product status. As cyanobacteria synthetic biology is still in its infancy, apart from the achievements made, the difficulties and challenges in the application and development of cyanobacteria genetic tool kits in biochemical synthesis, environmental monitoring, and remediation were assessed.
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Affiliation(s)
| | | | - Jinlu Hu
- School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China; (X.L.); (K.T.)
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2
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Kurt E, Qin J, Williams A, Zhao Y, Xie D. Perspectives for Using CO 2 as a Feedstock for Biomanufacturing of Fuels and Chemicals. Bioengineering (Basel) 2023; 10:1357. [PMID: 38135948 PMCID: PMC10740661 DOI: 10.3390/bioengineering10121357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Microbial cell factories offer an eco-friendly alternative for transforming raw materials into commercially valuable products because of their reduced carbon impact compared to conventional industrial procedures. These systems often depend on lignocellulosic feedstocks, mainly pentose and hexose sugars. One major hurdle when utilizing these sugars, especially glucose, is balancing carbon allocation to satisfy energy, cofactor, and other essential component needs for cellular proliferation while maintaining a robust yield. Nearly half or more of this carbon is inevitably lost as CO2 during the biosynthesis of regular metabolic necessities. This loss lowers the production yield and compromises the benefit of reducing greenhouse gas emissions-a fundamental advantage of biomanufacturing. This review paper posits the perspectives of using CO2 from the atmosphere, industrial wastes, or the exhausted gases generated in microbial fermentation as a feedstock for biomanufacturing. Achieving the carbon-neutral or -negative goals is addressed under two main strategies. The one-step strategy uses novel metabolic pathway design and engineering approaches to directly fix the CO2 toward the synthesis of the desired products. Due to the limitation of the yield and efficiency in one-step fixation, the two-step strategy aims to integrate firstly the electrochemical conversion of the exhausted CO2 into C1/C2 products such as formate, methanol, acetate, and ethanol, and a second fermentation process to utilize the CO2-derived C1/C2 chemicals or co-utilize C5/C6 sugars and C1/C2 chemicals for product formation. The potential and challenges of using CO2 as a feedstock for future biomanufacturing of fuels and chemicals are also discussed.
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Affiliation(s)
- Elif Kurt
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Jiansong Qin
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Alexandria Williams
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Youbo Zhao
- Physical Sciences Inc., 20 New England Business Ctr., Andover, MA 01810, USA;
| | - Dongming Xie
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
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3
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Germann AT, Nakielski A, Dietsch M, Petzel T, Moser D, Triesch S, Westhoff P, Axmann IM. A systematic overexpression approach reveals native targets to increase squalene production in Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2023; 14:1024981. [PMID: 37324717 PMCID: PMC10266222 DOI: 10.3389/fpls.2023.1024981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 04/28/2023] [Indexed: 06/17/2023]
Abstract
Cyanobacteria are a promising platform for the production of the triterpene squalene (C30), a precursor for all plant and animal sterols, and a highly attractive intermediate towards triterpenoids, a large group of secondary plant metabolites. Synechocystis sp. PCC 6803 natively produces squalene from CO2 through the MEP pathway. Based on the predictions of a constraint-based metabolic model, we took a systematic overexpression approach to quantify native Synechocystis gene's impact on squalene production in a squalene-hopene cyclase gene knock-out strain (Δshc). Our in silico analysis revealed an increased flux through the Calvin-Benson-Bassham cycle in the Δshc mutant compared to the wildtype, including the pentose phosphate pathway, as well as lower glycolysis, while the tricarboxylic acid cycle predicted to be downregulated. Further, all enzymes of the MEP pathway and terpenoid synthesis, as well as enzymes from the central carbon metabolism, Gap2, Tpi and PyrK, were predicted to positively contribute to squalene production upon their overexpression. Each identified target gene was integrated into the genome of Synechocystis Δshc under the control of the rhamnose-inducible promoter Prha. Squalene production was increased in an inducer concentration dependent manner through the overexpression of most predicted genes, which are genes of the MEP pathway, ispH, ispE, and idi, leading to the greatest improvements. Moreover, we were able to overexpress the native squalene synthase gene (sqs) in Synechocystis Δshc, which reached the highest production titer of 13.72 mg l-1 reported for squalene in Synechocystis sp. PCC 6803 so far, thereby providing a promising and sustainable platform for triterpene production.
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Affiliation(s)
- Anna T. Germann
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andreas Nakielski
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Maximilian Dietsch
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tim Petzel
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Daniel Moser
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Sebastian Triesch
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Philipp Westhoff
- Plant Metabolism and Metabolomics Laboratory, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ilka M. Axmann
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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4
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Goodchild-Michelman IM, Church GM, Schubert MG, Tang TC. Light and carbon: Synthetic biology toward new cyanobacteria-based living biomaterials. Mater Today Bio 2023; 19:100583. [PMID: 36846306 PMCID: PMC9945787 DOI: 10.1016/j.mtbio.2023.100583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/30/2023] [Accepted: 02/10/2023] [Indexed: 02/13/2023] Open
Abstract
Cyanobacteria are ideal candidates to use in developing carbon neutral and carbon negative technologies; they are efficient photosynthesizers and amenable to genetic manipulation. Over the past two decades, researchers have demonstrated that cyanobacteria can make sustainable, useful biomaterials, many of which are engineered living materials. However, we are only beginning to see such technologies applied at an industrial scale. In this review, we explore the ways in which synthetic biology tools enable the development of cyanobacteria-based biomaterials. First we give an overview of the ecological and biogeochemical importance of cyanobacteria and the work that has been done using cyanobacteria to create biomaterials so far. This is followed by a discussion of commonly used cyanobacteria strains and synthetic biology tools that exist to engineer cyanobacteria. Then, three case studies-bioconcrete, biocomposites, and biophotovoltaics-are explored as potential applications of synthetic biology in cyanobacteria-based materials. Finally, challenges and future directions of cyanobacterial biomaterials are discussed.
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Affiliation(s)
- Isabella M. Goodchild-Michelman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - George M. Church
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Max G. Schubert
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Tzu-Chieh Tang
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
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5
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Kumar N, Kar S, Shukla P. Role of regulatory pathways and multi-omics approaches for carbon capture and mitigation in cyanobacteria. BIORESOURCE TECHNOLOGY 2022; 366:128104. [PMID: 36257524 DOI: 10.1016/j.biortech.2022.128104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Cyanobacteria are known for their metabolic potential and carbon capture and sequestration capabilities. These cyanobacteria are not only an effective source for carbon minimization and resource mobilization into value-added products for biotechnological gains. The present review focuses on the detailed description of carbon capture mechanisms exerted by the various cyanobacterial strains, the role of important regulatory pathways, and their subsequent genes responsible for such mechanisms. Moreover, this review will also describe effectual mechanisms of central carbon metabolism like isoprene synthesis, ethylene production, MEP pathway, and the role of Glyoxylate shunt in the carbon sequestration mechanisms. This review also describes some interesting facets of using carbon assimilation mechanisms for valuable bio-products. The role of regulatory pathways and multi-omics approaches in cyanobacteria will not only be crucial towards improving carbon utilization but also will give new insights into utilizing cyanobacterial bioresource for carbon neutrality.
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Affiliation(s)
- Niwas Kumar
- Society for Research and Initiatives for Sustainable Technologies and Institutions, Navrangapura, Ahmedabad 380009, India
| | - Srabani Kar
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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6
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CRISPR-based metabolic engineering in non-model microorganisms. Curr Opin Biotechnol 2022; 75:102698. [PMID: 35217297 DOI: 10.1016/j.copbio.2022.102698] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/20/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022]
Abstract
Non-model microorganisms possess unique and versatile metabolic characteristics, offering great opportunities as cell factories for biosynthesis of target products. However, lack of efficient genetic tools for pathway engineering represents a big challenge to unlock the full production potential of these microbes. Over the past years, CRISPR systems have been extensively developed and applied to domesticate non-model microorganisms. In this paper, we summarize the current significant advances in designing and constructing CRISPR-mediated genetic modification systems in non-model microorganisms, such as bacteria, fungi and cyanobacteria. We particularly put emphasis on reviewing some successful implementations in metabolic pathway engineering via CRISPR-based genome editing tools. Moreover, the current barriers and future perspectives on improving the editing efficiency of CRISPR systems in non-model microorganisms are also discussed.
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7
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Andrews F, Faulkner M, Toogood HS, Scrutton NS. Combinatorial use of environmental stresses and genetic engineering to increase ethanol titres in cyanobacteria. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:240. [PMID: 34920731 PMCID: PMC8684110 DOI: 10.1186/s13068-021-02091-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/05/2021] [Indexed: 06/07/2023]
Abstract
Current industrial bioethanol production by yeast through fermentation generates carbon dioxide. Carbon neutral bioethanol production by cyanobacteria uses biological fixation (photosynthesis) of carbon dioxide or other waste inorganic carbon sources, whilst being sustainable and renewable. The first ethanologenic cyanobacterial process was developed over two decades ago using Synechococcus elongatus PCC 7942, by incorporating the recombinant pdc and adh genes from Zymomonas mobilis. Further engineering has increased bioethanol titres 24-fold, yet current levels are far below what is required for industrial application. At the heart of the problem is that the rate of carbon fixation cannot be drastically accelerated and carbon partitioning towards bioethanol production impacts on cell fitness. Key progress has been achieved by increasing the precursor pyruvate levels intracellularly, upregulating synthetic genes and knocking out pathways competing for pyruvate. Studies have shown that cyanobacteria accumulate high proportions of carbon reserves that are mobilised under specific environmental stresses or through pathway engineering to increase ethanol production. When used in conjunction with specific genetic knockouts, they supply significantly more carbon for ethanol production. This review will discuss the progress in generating ethanologenic cyanobacteria through chassis engineering, and exploring the impact of environmental stresses on increasing carbon flux towards ethanol production.
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Affiliation(s)
- Fraser Andrews
- EPSRC/BBSRC Future Biomanufacturing Research Hub, BBSRC/EPSRC Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN, UK
| | - Matthew Faulkner
- EPSRC/BBSRC Future Biomanufacturing Research Hub, BBSRC/EPSRC Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN, UK
| | - Helen S Toogood
- EPSRC/BBSRC Future Biomanufacturing Research Hub, BBSRC/EPSRC Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN, UK
| | - Nigel S Scrutton
- EPSRC/BBSRC Future Biomanufacturing Research Hub, BBSRC/EPSRC Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
- C3 Biotechnologies Ltd, 20 Mannin Way, Lancaster Business Park, Caton Road, Lancaster, LA1 3SW, Lancashire, UK.
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8
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Jeong Y, Hong SJ, Cho SH, Yoon S, Lee H, Choi HK, Kim DM, Lee CG, Cho S, Cho BK. Multi-Omic Analyses Reveal Habitat Adaptation of Marine Cyanobacterium Synechocystis sp. PCC 7338. Front Microbiol 2021; 12:667450. [PMID: 34054774 PMCID: PMC8155712 DOI: 10.3389/fmicb.2021.667450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are considered as promising microbial cell factories producing a wide array of bio-products. Among them, Synechocystis sp. PCC 7338 has the advantage of growing in seawater, rather than requiring arable land or freshwater. Nonetheless, how this marine cyanobacterium grows under the high salt stress condition remains unknown. Here, we determined its complete genome sequence with the embedded regulatory elements and analyzed the transcriptional changes in response to a high-salt environment. Complete genome sequencing revealed a 3.70 mega base pair genome and three plasmids with a total of 3,589 genes annotated. Differential RNA-seq and Term-seq data aligned to the complete genome provided genome-wide information on genetic regulatory elements, including promoters, ribosome-binding sites, 5'- and 3'-untranslated regions, and terminators. Comparison with freshwater Synechocystis species revealed Synechocystis sp. PCC 7338 genome encodes additional genes, whose functions are related to ion channels to facilitate the adaptation to high salt and high osmotic pressure. Furthermore, a ferric uptake regulator binding motif was found in regulatory regions of various genes including SigF and the genes involved in energy metabolism, suggesting the iron-regulatory network is connected to not only the iron acquisition, but also response to high salt stress and photosynthesis. In addition, the transcriptomics analysis demonstrated a cyclic electron transport through photosystem I was actively used by the strain to satisfy the demand for ATP under high-salt environment. Our comprehensive analyses provide pivotal information to elucidate the genomic functions and regulations in Synechocystis sp. PCC 7338.
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Affiliation(s)
- Yujin Jeong
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seong-Joo Hong
- Department of Biological Engineering, Inha University, Incheon, South Korea.,Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea
| | - Sang-Hyeok Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seonghoon Yoon
- Department of Biological Engineering, Inha University, Incheon, South Korea.,Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea
| | - Hookeun Lee
- Institute of Pharmaceutical Research, College of Pharmacy, Gachon University, Incheon, South Korea
| | | | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, South Korea
| | - Choul-Gyun Lee
- Department of Biological Engineering, Inha University, Incheon, South Korea.,Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea
| | - Suhyung Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,Innovative Biomaterials Center, KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,Innovative Biomaterials Center, KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,Intelligent Synthetic Biology Center, Daejeon, South Korea
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9
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Jeong Y, Cho SH, Lee H, Choi HK, Kim DM, Lee CG, Cho S, Cho BK. Current Status and Future Strategies to Increase Secondary Metabolite Production from Cyanobacteria. Microorganisms 2020; 8:E1849. [PMID: 33255283 PMCID: PMC7761380 DOI: 10.3390/microorganisms8121849] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/15/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022] Open
Abstract
Cyanobacteria, given their ability to produce various secondary metabolites utilizing solar energy and carbon dioxide, are a potential platform for sustainable production of biochemicals. Until now, conventional metabolic engineering approaches have been applied to various cyanobacterial species for enhanced production of industrially valued compounds, including secondary metabolites and non-natural biochemicals. However, the shortage of understanding of cyanobacterial metabolic and regulatory networks for atmospheric carbon fixation to biochemical production and the lack of available engineering tools limit the potential of cyanobacteria for industrial applications. Recently, to overcome the limitations, synthetic biology tools and systems biology approaches such as genome-scale modeling based on diverse omics data have been applied to cyanobacteria. This review covers the synthetic and systems biology approaches for advanced metabolic engineering of cyanobacteria.
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Affiliation(s)
- Yujin Jeong
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Sang-Hyeok Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Hookeun Lee
- Institute of Pharmaceutical Research, College of Pharmacy, Gachon University, Incheon 21999, Korea;
| | | | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Korea;
| | - Choul-Gyun Lee
- Department of Biological Engineering, Inha University, Incheon 22212, Korea;
| | - Suhyung Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Byung-Kwan Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
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10
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Behle A, Saake P, Germann AT, Dienst D, Axmann IM. Comparative Dose-Response Analysis of Inducible Promoters in Cyanobacteria. ACS Synth Biol 2020; 9:843-855. [PMID: 32134640 DOI: 10.1021/acssynbio.9b00505] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Design and implementation of synthetic biological circuits highly depends on well-characterized, robust promoters with predictable input-output responses. While great progress has been made with heterotrophic model organisms such as Escherichia coli, the available variety of tunable promoter parts for phototrophic cyanobacteria is still limited. Commonly used synthetic and semisynthetic promoters show weak dynamic ranges or no regulation at all in cyanobacterial models. Well-controlled alternatives such as native metal-responsive promoters, however, pose the problems of inducer toxicity and lacking orthogonality. Here, we present the comparative assessment of dose-response functions of four different inducible promoter systems in the model cyanobacterium Synechocystis sp. PCC 6803. Using the novel bimodular reporter plasmid pSHDY, dose-response dynamics of the re-established vanillate-inducible promoter PvanCC was compared to the previously described rhamnose-inducible Prha, the anhydrotetracycline-inducible PL03, and the Co2+-inducible PcoaT. We estimate individual advantages and disadvantages regarding dynamic range and strength of each promoter, also in comparison with well-established constitutive systems. We observed a delicate balance between transcription factor toxicity and sufficient expression to obtain a dose-dependent response to the inducer. In summary, we expand the current understanding and employability of inducible promoters in cyanobacteria, facilitating the scalability and robustness of synthetic regulatory network designs and of complex metabolic pathway engineering strategies.
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Affiliation(s)
- Anna Behle
- Institute for Synthetic Microbiology, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Pia Saake
- Institute for Synthetic Microbiology, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Anna T. Germann
- Institute for Synthetic Microbiology, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
| | - Dennis Dienst
- Department of Chemistry − Ångström, Uppsala University, 75120 Uppsala, Sweden
| | - Ilka M. Axmann
- Institute for Synthetic Microbiology, Heinrich Heine University Duesseldorf, 40225 Duesseldorf, Germany
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11
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Evaluation of New Genetic Toolkits and Their Role for Ethanol Production in Cyanobacteria. ENERGIES 2019. [DOI: 10.3390/en12183515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Since the public awareness for climate change has risen, increasing scientific effort has been made to find and develop alternative resources and production processes to reduce the dependency on petrol-based fuels and chemicals of our society. Among others, the biotechnological fuel production, as for example fermenting sugar-rich crops to ethanol, is one of the main strategies. For this purpose, various classical production systems like Escherichia coli or Saccharomyces cerevisiae are used and have been optimized via genetic modifications. Despite the progress made, this strategy competes for nutritional resources and agricultural land. To overcome this problem, various attempts were made for direct photosynthetic driven ethanol synthesis with different microalgal species including cyanobacteria. However, compared to existing platforms, the development of cyanobacteria as photoautotrophic cell factories has just started, and accordingly, the ethanol yield of established production systems is still unreached. This is mainly attributed to low ethanol tolerance levels of cyanobacteria and there is still potential for optimizing the cyanobacteria towards alternative gene expression systems. Meanwhile, several improvements were made by establishing new toolboxes for synthetic biology offering new possibilities for advanced genetic modifications of cyanobacteria. Here, current achievements and innovations of those new molecular tools are discussed.
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12
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Bartasun P, Prandi N, Storch M, Aknin Y, Bennett M, Palma A, Baldwin G, Sakuragi Y, Jones PR, Rowland J. The effect of modulating the quantity of enzymes in a model ethanol pathway on metabolic flux in Synechocystis sp. PCC 6803. PeerJ 2019; 7:e7529. [PMID: 31523505 PMCID: PMC6717505 DOI: 10.7717/peerj.7529] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/22/2019] [Indexed: 12/17/2022] Open
Abstract
Synthetic metabolism allows new metabolic capabilities to be introduced into strains for biotechnology applications. Such engineered metabolic pathways are unlikely to function optimally as initially designed and native metabolism may not efficiently support the introduced pathway without further intervention. To develop our understanding of optimal metabolic engineering strategies, a two-enzyme ethanol pathway consisting of pyruvate decarboxylase and acetaldehyde reductase was introduced into Synechocystis sp. PCC 6803. We characteriseda new set of ribosome binding site sequences in Synechocystis sp. PCC 6803 providing a range of translation strengths for different genes under test. The effect of ribosome-bindingsite sequence, operon design and modifications to native metabolism on pathway flux was analysed by HPLC. The accumulation of all introduced proteins was also quantified using selected reaction monitoring mass spectrometry. Pathway productivity was more strongly dependent on the accumulation of pyruvate decarboxylase than acetaldehyde reductase. In fact, abolishment of reductase over-expression resulted in the greatest ethanol productivity, most likely because strains harbouringsingle-gene constructs accumulated more pyruvate decarboxylase than strains carrying any of the multi-gene constructs. Overall, several lessons were learned. Firstly, the expression level of the first gene in anyoperon influenced the expression level of subsequent genes, demonstrating that translational coupling can also occur in cyanobacteria. Longer operons resulted in lower protein abundance for proximally-encoded cistrons. And, implementation of metabolic engineering strategies that have previously been shown to enhance the growth or yield of pyruvate dependent products, through co-expression with pyruvate kinase and/or fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase, indicated that other factors had greater control over growth and metabolic flux under the tested conditions.
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Affiliation(s)
- Paulina Bartasun
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Nicole Prandi
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Marko Storch
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
| | - Yarin Aknin
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot, Israel
| | - Mark Bennett
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Arianna Palma
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Geoff Baldwin
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
| | - Yumiko Sakuragi
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Patrik R Jones
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
| | - John Rowland
- Department of Life Sciences, Imperial College London, London, United Kingdom
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13
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Kelly CL, Taylor GM, Šatkutė A, Dekker L, Heap JT. Transcriptional Terminators Allow Leak-Free Chromosomal Integration of Genetic Constructs in Cyanobacteria. Microorganisms 2019; 7:microorganisms7080263. [PMID: 31426276 PMCID: PMC6723963 DOI: 10.3390/microorganisms7080263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/09/2019] [Accepted: 08/12/2019] [Indexed: 01/10/2023] Open
Abstract
Cyanobacteria are promising candidates for sustainable bioproduction of chemicals from sunlight and carbon dioxide. However, the genetics and metabolism of cyanobacteria are less well understood than those of model heterotrophic organisms, and the suite of well-characterised cyanobacterial genetic tools and parts is less mature and complete. Transcriptional terminators use specific RNA structures to halt transcription and are routinely used in both natural and recombinant contexts to achieve independent control of gene expression and to ‘insulate’ genes and operons from one another. Insulating gene expression can be particularly important when heterologous or synthetic genetic constructs are inserted at genomic locations where transcriptional read-through from chromosomal promoters occurs, resulting in poor control of expression of the introduced genes. To date, few terminators have been described and characterised in cyanobacteria. In this work, nineteen heterologous, synthetic or putative native Rho-independent (intrinsic) terminators were tested in the model freshwater cyanobacterium, Synechocystis sp. PCC 6803, from which eleven strong terminators were identified. A subset of these strong terminators was then used to successfully insulate a chromosomally–integrated, rhamnose-inducible rhaBAD expression system from hypothesised ‘read-through’ from a neighbouring chromosomal promoter, resulting in greatly improved inducible control. The addition of validated strong terminators to the cyanobacterial toolkit will allow improved independent control of introduced genes.
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Affiliation(s)
- Ciarán L Kelly
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - George M Taylor
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Aistė Šatkutė
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Linda Dekker
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - John T Heap
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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CyanoFactory, a European consortium to develop technologies needed to advance cyanobacteria as chassis for production of chemicals and fuels. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101510] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Khan AZ, Bilal M, Mehmood S, Sharma A, Iqbal HMN. State-of-the-Art Genetic Modalities to Engineer Cyanobacteria for Sustainable Biosynthesis of Biofuel and Fine-Chemicals to Meet Bio-Economy Challenges. Life (Basel) 2019; 9:life9030054. [PMID: 31252652 PMCID: PMC6789541 DOI: 10.3390/life9030054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/15/2019] [Accepted: 06/26/2019] [Indexed: 02/07/2023] Open
Abstract
In recent years, metabolic engineering of microorganisms has attained much research interest to produce biofuels and industrially pertinent chemicals. Owing to the relatively fast growth rate, genetic malleability, and carbon neutral production process, cyanobacteria has been recognized as a specialized microorganism with a significant biotechnological perspective. Metabolically engineering cyanobacterial strains have shown great potential for the photosynthetic production of an array of valuable native or non-native chemicals and metabolites with profound agricultural and pharmaceutical significance using CO2 as a building block. In recent years, substantial improvements in developing and introducing novel and efficient genetic tools such as genome-scale modeling, high throughput omics analyses, synthetic/system biology tools, metabolic flux analysis and clustered regularly interspaced short palindromic repeats (CRISPR)-associated nuclease (CRISPR/cas) systems have been made for engineering cyanobacterial strains. Use of these tools and technologies has led to a greater understanding of the host metabolism, as well as endogenous and heterologous carbon regulation mechanisms which consequently results in the expansion of maximum productive ability and biochemical diversity. This review summarizes recent advances in engineering cyanobacteria to produce biofuel and industrially relevant fine chemicals of high interest. Moreover, the development and applications of cutting-edge toolboxes such as the CRISPR-cas9 system, synthetic biology, high-throughput "omics", and metabolic flux analysis to engineer cyanobacteria for large-scale cultivation are also discussed.
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Affiliation(s)
- Aqib Zafar Khan
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Shahid Mehmood
- Bio-X Institute, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200030, China
| | - Ashutosh Sharma
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Epigmenio Gonzalez 500, Queretaro CP 76130, Mexico
| | - Hafiz M N Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey CP 64849, N.L., Mexico.
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Li H, Zhao Q, Huang H. Current states and challenges of salt-affected soil remediation by cyanobacteria. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 669:258-272. [PMID: 30878933 DOI: 10.1016/j.scitotenv.2019.03.104] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/23/2019] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
Natural and human activities lead to soil degradation and soil salinization. The decrease of farmlands threatens food security. There are approximately 1 billion ha salt-affected soils all over of world, which can be made available resources after chemical, physical and biological remediation. Nostoc, Anabaena and other cyanobacterial species have outstanding capabilities, such as the ability to fix nitrogen from the air, produce an extracellular matrix and produce compatible solutes. The remediation of salt-affected soil is a complex and difficult task. During the past years, much new research has been conducted that shows that cyanobacteria are effective for salt-affected soil remediation in laboratory studies and field trials. The related mechanisms for both salt tolerance and salt-affected soil remediation were also evaluated from the perspective of biochemistry, molecular biology and systems biology. The effect of cyanobacteria on salt-affected soil is related to nitrogen fixation and other mechanisms. There are complicated interactions among cyanobacteria, bacteria, fungi and the soil. The interaction between cyanobacteria and salt-tolerant plants should be considered if the cyanobacterium is utilized to improve the soil fertility in addition to performing soil remediation. It is critical to re-establish the micro-ecology in salt-affected soils and improve the salt affected soil remediation efficiency. The first challenge is the selection of suitable cyanobacterial strain. The co-culture of cyanobacteria and bacteria is also potential approach. The cultivation of cyanobacteria on a large scale should be optimized to improve productivity and decrease cost. The development of bio-remediating agents for salt-affected soil remediation also relies on other technical problems, such as harvesting and contamination control. The application of cyanobacteria in salt-affected soil remediation will reconstruct green agriculture and promote the sustainable development of human society.
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Affiliation(s)
- Han Li
- School of Pharmaceutical Science, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, People's Republic of China
| | - Quanyu Zhao
- School of Pharmaceutical Science, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, People's Republic of China.
| | - He Huang
- School of Pharmaceutical Science, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, People's Republic of China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), People's Republic of China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China
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Xia P, Ling H, Foo JL, Chang MW. Synthetic Biology Toolkits for Metabolic Engineering of Cyanobacteria. Biotechnol J 2019; 14:e1800496. [DOI: 10.1002/biot.201800496] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/19/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Peng‐Fei Xia
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
| | - Hua Ling
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
| | - Jee Loon Foo
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
| | - Matthew Wook Chang
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
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18
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Transcription in cyanobacteria: a distinctive machinery and putative mechanisms. Biochem Soc Trans 2019; 47:679-689. [DOI: 10.1042/bst20180508] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/11/2019] [Accepted: 02/04/2019] [Indexed: 02/03/2023]
Abstract
Abstract
Transcription in cyanobacteria involves several fascinating features. Cyanobacteria comprise one of the very few groups in which no proofreading factors (Gre homologues) have been identified. Gre factors increase the efficiency of RNA cleavage, therefore helping to maintain the fidelity of the RNA transcript and assist in the resolution of stalled RNAPs to prevent genome damage. The vast majority of bacterial species encode at least one of these highly conserved factors and so their absence in cyanobacteria is intriguing. Additionally, the largest subunit of bacterial RNAP has undergone a split in cyanobacteria to form two subunits and the SI3 insertion within the integral trigger loop element is roughly 3.5 times larger than in Escherichia coli. The Rho termination factor also appears to be absent, leaving cyanobacteria to rely solely on an intrinsic termination mechanism. Furthermore, cyanobacteria must be able to respond to environment signals such as light intensity and tightly synchronise gene expression and other cell activities to a circadian rhythm.
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Santos-Merino M, Singh AK, Ducat DC. New Applications of Synthetic Biology Tools for Cyanobacterial Metabolic Engineering. Front Bioeng Biotechnol 2019; 7:33. [PMID: 30873404 PMCID: PMC6400836 DOI: 10.3389/fbioe.2019.00033] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/05/2019] [Indexed: 01/25/2023] Open
Abstract
Cyanobacteria are promising microorganisms for sustainable biotechnologies, yet unlocking their potential requires radical re-engineering and application of cutting-edge synthetic biology techniques. In recent years, the available devices and strategies for modifying cyanobacteria have been increasing, including advances in the design of genetic promoters, ribosome binding sites, riboswitches, reporter proteins, modular vector systems, and markerless selection systems. Because of these new toolkits, cyanobacteria have been successfully engineered to express heterologous pathways for the production of a wide variety of valuable compounds. Cyanobacterial strains with the potential to be used in real-world applications will require the refinement of genetic circuits used to express the heterologous pathways and development of accurate models that predict how these pathways can be best integrated into the larger cellular metabolic network. Herein, we review advances that have been made to translate synthetic biology tools into cyanobacterial model organisms and summarize experimental and in silico strategies that have been employed to increase their bioproduction potential. Despite the advances in synthetic biology and metabolic engineering during the last years, it is clear that still further improvements are required if cyanobacteria are to be competitive with heterotrophic microorganisms for the bioproduction of added-value compounds.
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Affiliation(s)
- María Santos-Merino
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Amit K. Singh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Daniel C. Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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20
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Gordon GC, Pfleger BF. Regulatory Tools for Controlling Gene Expression in Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1080:281-315. [PMID: 30091100 PMCID: PMC6662922 DOI: 10.1007/978-981-13-0854-3_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are attractive hosts for converting carbon dioxide and sunlight into desirable chemical products. To engineer these organisms and manipulate their metabolic pathways, the biotechnology community has developed genetic tools to control gene expression. Many native cyanobacterial promoters and related sequence elements have been used to regulate genes of interest, and heterologous tools that use non-native small molecules to induce gene expression have been demonstrated. Overall, IPTG-based induction systems seem to be leaky and initially demonstrate small dynamic ranges in cyanobacteria. Consequently, a variety of other induction systems have been optimized to enable tighter control of gene expression. Tools require significant optimization because they function quite differently in cyanobacteria when compared to analogous use in model heterotrophs. We hypothesize that these differences are due to fundamental differences in physiology between organisms. This review is not intended to summarize all known products made in cyanobacteria nor the performance (titer, rate, yield) of individual strains, but instead will focus on the genetic tools and the inherent aspects of cellular physiology that influence gene expression in cyanobacteria.
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Affiliation(s)
- Gina C Gordon
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA.
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21
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Metabolic engineering tools in model cyanobacteria. Metab Eng 2018; 50:47-56. [DOI: 10.1016/j.ymben.2018.03.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 12/27/2022]
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22
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Yao R, Liu D, Jia X, Zheng Y, Liu W, Xiao Y. CRISPR-Cas9/Cas12a biotechnology and application in bacteria. Synth Syst Biotechnol 2018; 3:135-149. [PMID: 30345399 PMCID: PMC6190536 DOI: 10.1016/j.synbio.2018.09.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/24/2018] [Accepted: 09/25/2018] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas technologies have greatly reshaped the biology field. In this review, we discuss the CRISPR-Cas with a particular focus on the associated technologies and applications of CRISPR-Cas9 and CRISPR-Cas12a, which have been most widely studied and used. We discuss the biological mechanisms of CRISPR-Cas as immune defense systems, recently-discovered anti-CRISPR-Cas systems, and the emerging Cas variants (such as xCas9 and Cas13) with unique characteristics. Then, we highlight various CRISPR-Cas biotechnologies, including nuclease-dependent genome editing, CRISPR gene regulation (including CRISPR interference/activation), DNA/RNA base editing, and nucleic acid detection. Last, we summarize up-to-date applications of the biotechnologies for synthetic biology and metabolic engineering in various bacterial species.
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Affiliation(s)
- Ruilian Yao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Di Liu
- Department of Biomass Science and Conversion Technology, Sandia National Laboratories, Livermore, CA 94551, USA
| | - Xiao Jia
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yuan Zheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wei Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yi Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
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Behler J, Vijay D, Hess WR, Akhtar MK. CRISPR-Based Technologies for Metabolic Engineering in Cyanobacteria. Trends Biotechnol 2018; 36:996-1010. [DOI: 10.1016/j.tibtech.2018.05.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 12/16/2022]
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Xiao Y, Wang S, Rommelfanger S, Balassy A, Barba-Ostria C, Gu P, Galazka JM, Zhang F. Developing a Cas9-based tool to engineer native plasmids in Synechocystis sp. PCC 6803. Biotechnol Bioeng 2018; 115:2305-2314. [PMID: 29896914 DOI: 10.1002/bit.26747] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 05/06/2018] [Accepted: 06/05/2018] [Indexed: 01/05/2023]
Abstract
The oxygenic photosynthetic bacterium Synechocystis sp. PCC 6803 (S6803) is a model cyanobacterium widely used for fundamental research and biotechnology applications. Due to its polyploidy, existing methods for genome engineering of S6803 require multiple rounds of selection to modify all genome copies, which is time-consuming and inefficient. In this study, we engineered the Cas9 tool for one-step, segregation-free genome engineering. We further used our Cas9 tool to delete three of seven S6803 native plasmids. Our results show that all three small-size native plasmids, but not the large-size native plasmids, can be deleted with this tool. To further facilitate heterologous gene expression in S6803, a shuttle vector based on the native plasmid pCC5.2 was created. The shuttle vector can be introduced into Cas9-containing S6803 in one step without requiring segregation and can be stably maintained without antibiotic pressure for at least 30 days. Moreover, genes encoded on the shuttle vector remain functional after 30 days of continuous cultivation without selective pressure. Thus, this study provides a set of new tools for rapid modification of the S6803 genome and for stable expression of heterologous genes, potentially facilitating both fundamental research and biotechnology applications using S6803.
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Affiliation(s)
- Yi Xiao
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missori
- Present address: State Key Laboratory for Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Shaojie Wang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missori
| | - Sarah Rommelfanger
- Division of Biological & Biomedical Sciences, Washington University in St. Louis, Saint Louis, Missori
| | - Andrea Balassy
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missori
| | - Carlos Barba-Ostria
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missori
- Present address: Department of Health Sciences, Ambato Technical University, Ambato, Ecuador
| | - Pengfei Gu
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missori
| | - Jonathan M Galazka
- Space Biosciences Division, Ames Research Center, National Aeronautics and Space Administration, Mountain View, California
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missori
- Division of Biological & Biomedical Sciences, Washington University in St. Louis, Saint Louis, Missori
- Institute of Materials Science & Engineering, Washington University in St. Louis, Saint Louis, Misssori
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Sengupta A, Pakrasi HB, Wangikar PP. Recent advances in synthetic biology of cyanobacteria. Appl Microbiol Biotechnol 2018; 102:5457-5471. [PMID: 29744631 DOI: 10.1007/s00253-018-9046-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 12/11/2022]
Abstract
Cyanobacteria are attractive hosts that can be engineered for the photosynthetic production of fuels, fine chemicals, and proteins from CO2. Moreover, the responsiveness of these photoautotrophs towards different environmental signals, such as light, CO2, diurnal cycle, and metals make them potential hosts for the development of biosensors. However, engineering these hosts proves to be a challenging and lengthy process. Synthetic biology can make the process of biological engineering more predictable through the use of standardized biological parts that are well characterized and tools to assemble them. While significant progress has been made with model heterotrophic organisms, many of the parts and tools are not portable in cyanobacteria. Therefore, efforts are underway to develop and characterize parts derived from cyanobacteria. In this review, we discuss the reported parts and tools with the objective to develop cyanobacteria as cell factories or biosensors. We also discuss the issues related to characterization, tunability, portability, and the need to develop enabling technologies to engineer this "green" chassis.
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Affiliation(s)
- Annesha Sengupta
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO, USA.,Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
| | - Pramod P Wangikar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. .,DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. .,Wadhwani Research Center for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
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Liu D, Pakrasi HB. Exploring native genetic elements as plug-in tools for synthetic biology in the cyanobacterium Synechocystis sp. PCC 6803. Microb Cell Fact 2018; 17:48. [PMID: 29580240 PMCID: PMC5868059 DOI: 10.1186/s12934-018-0897-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 03/21/2018] [Indexed: 11/24/2022] Open
Abstract
Background The unicellular cyanobacterium Synechocystis sp. PCC 6803 has been widely used as a photoautotrophic host for synthetic biology studies. However, as a green chassis to capture CO2 for biotechnological applications, the genetic toolbox for Synechocystis 6803 is still a limited factor. Results We systematically characterized endogenous genetic elements of Synechocystis 6803, including promoters, ribosome binding sites, transcription terminators, and plasmids. Expression from twelve native promoters was compared by measuring fluorescence from the reporter protein EYFP in an identical setup, exhibiting an 8000-fold range of promoter activities. Moreover, we measured the strength of twenty native ribosome binding sites and eight native terminators, indicating their influence on the expression of the reporter genes. In addition, two shuttle vectors, pCA-UC118 and pCB-SC101, capable of replication in both Synechocystis 6803 and E. coli were constructed. Expression of reporter proteins were significantly enhanced in cells containing these new plasmids, thus providing superior gene expression platforms in this cyanobacterium. Conclusions The results of this study provide useful and well characterized native tools for bioengineering work in the model cyanobacterium Synechocystis 6803. Electronic supplementary material The online version of this article (10.1186/s12934-018-0897-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Deng Liu
- Department of Biology, Washington University, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA.
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Thiel K, Mulaku E, Dandapani H, Nagy C, Aro EM, Kallio P. Translation efficiency of heterologous proteins is significantly affected by the genetic context of RBS sequences in engineered cyanobacterium Synechocystis sp. PCC 6803. Microb Cell Fact 2018; 17:34. [PMID: 29499707 PMCID: PMC5834881 DOI: 10.1186/s12934-018-0882-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 02/23/2018] [Indexed: 12/26/2022] Open
Abstract
Background Photosynthetic cyanobacteria have been studied as potential host organisms for direct solar-driven production of different carbon-based chemicals from CO2 and water, as part of the development of sustainable future biotechnological applications. The engineering approaches, however, are still limited by the lack of comprehensive information on most optimal expression strategies and validated species-specific genetic elements which are essential for increasing the intricacy, predictability and efficiency of the systems. This study focused on the systematic evaluation of the key translational control elements, ribosome binding sites (RBS), in the cyanobacterial host Synechocystis sp. PCC 6803, with the objective of expanding the palette of tools for more rigorous engineering approaches. Results An expression system was established for the comparison of 13 selected RBS sequences in Synechocystis, using several alternative reporter proteins (sYFP2, codon-optimized GFPmut3 and ethylene forming enzyme) as quantitative indicators of the relative translation efficiencies. The set-up was shown to yield highly reproducible expression patterns in independent analytical series with low variation between biological replicates, thus allowing statistical comparison of the activities of the different RBSs in vivo. While the RBSs covered a relatively broad overall expression level range, the downstream gene sequence was demonstrated in a rigorous manner to have a clear impact on the resulting translational profiles. This was expected to reflect interfering sequence-specific mRNA-level interaction between the RBS and the coding region, yet correlation between potential secondary structure formation and observed translation levels could not be resolved with existing in silico prediction tools. Conclusions The study expands our current understanding on the potential and limitations associated with the regulation of protein expression at translational level in engineered cyanobacteria. The acquired information can be used for selecting appropriate RBSs for optimizing over-expression constructs or multicistronic pathways in Synechocystis, while underlining the complications in predicting the activity due to gene-specific interactions which may reduce the translational efficiency for a given RBS-gene combination. Ultimately, the findings emphasize the need for additional characterized insulator sequence elements to decouple the interaction between the RBS and the coding region for future engineering approaches. Electronic supplementary material The online version of this article (10.1186/s12934-018-0882-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kati Thiel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Edita Mulaku
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Hariharan Dandapani
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Csaba Nagy
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Pauli Kallio
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland.
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Methods for enhancing cyanobacterial stress tolerance to enable improved production of biofuels and industrially relevant chemicals. Appl Microbiol Biotechnol 2018; 102:1617-1628. [DOI: 10.1007/s00253-018-8755-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/03/2018] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
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Du W, Burbano PC, Hellingwerf KJ, Branco Dos Santos F. Challenges in the Application of Synthetic Biology Toward Synthesis of Commodity Products by Cyanobacteria via "Direct Conversion". ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:3-26. [PMID: 30091089 DOI: 10.1007/978-981-13-0854-3_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cyanobacterial direct conversion of CO2 to several commodity chemicals has been recognized as a potential contributor to support the much-needed sustainable development of human societies. However, the feasibility of this "green conversion" hinders on our ability to overcome the hurdles presented by the natural evolvability of microbes. The latter may result in the genetic instability of engineered cyanobacterial strains leading to impaired productivity. This challenge is general to any "cell factory" approach in which the cells grow for multiple generations, and based on several studies carried out in different microbial hosts, we could identify that three distinct strategies have been proposed to tackle it. These are (1) to reduce microbial evolvability by decreasing the native mutation rate, (2) to align product formation with cell growth/fitness, and, paradoxically, (3) to efficiently reallocate cellular resources to product formation by uncoupling it from growth. The implementation of either of these strategies requires an advanced synthetic biology toolkit. Here, we review the existing methods available for cyanobacteria and identify areas of focus in which specific developments are still needed. Furthermore, we discuss how potentially stabilizing strategies may be used in combination leading to further increases of productivity while ensuring the stability of the cyanobacterial-based direct conversion process.
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Affiliation(s)
- Wei Du
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Patricia Caicedo Burbano
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Filipe Branco Dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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AraBAD Based Toolkit for Gene Expression and Metabolic Robustness Improvement in Synechococcus elongatus. Sci Rep 2017; 7:18059. [PMID: 29273782 PMCID: PMC5741739 DOI: 10.1038/s41598-017-17035-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/20/2017] [Indexed: 12/14/2022] Open
Abstract
As a novel chemical production platform, controllable and inducible modules in Synechococcus elongatus plus the ability of working in diurnal conditions are necessary. To the endeavors, inducible promoters, such as PTrc, have been refined from Escherichia coli, but the inducer isopropyl-β-D-thiogalactoside may cause several side-effects. Meanwhile, to promote the efficiency, photomixotrophic cultivation has been applied in S. elongatus with the additional organic carbon sources. In this study, we developed L-arabinose based modules consisted of both the PBAD inducible promoter and the metabolism of L-arabinose in S. elongatus, since L-arabinose is an ideal heterologous feedstock for its availability and economic and environmental benefits. As expected, we achieved homogeneous and linear expression of the exogenous reporter through the PBAD promoter, and the biomass increased in diurnal light condition via introducing L-arabinose metabolism pathway. Moreover, the combined AraBAD based toolkit containing both the PBAD inducible module and the L-arabinose metabolism module could obtain gene expression and metabolic robustness improvement in S. elongatus. With the only additive L-arabinose, the novel strategy may generate a win-win scenario for both regulation and metabolism for autotrophic bio-production platforms.
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Ueno K, Sakai Y, Shono C, Sakamoto I, Tsukakoshi K, Hihara Y, Sode K, Ikebukuro K. Applying a riboregulator as a new chromosomal gene regulation tool for higher glycogen production in Synechocystis sp. PCC 6803. Appl Microbiol Biotechnol 2017; 101:8465-8474. [PMID: 29038975 DOI: 10.1007/s00253-017-8570-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 09/18/2017] [Accepted: 09/26/2017] [Indexed: 11/29/2022]
Abstract
Cyanobacteria are one of the most attractive hosts for biofuel production; however, genetic approaches to regulate specific chromosomal genes in cyanobacteria remain limited. With the aim of developing a novel method to regulate chromosomal gene expression in cyanobacteria, we focused on riboregulatory technology. Riboregulators are composed of two RNA fragments whose interaction leads to target gene regulation with high specificity. In this study, we inserted a riboregulator sequence upstream of the chromosomal gene encoding AbrB-like transcriptional regulator, cyAbrB2, to investigate the utility of this tool. The inserted riboregulator was able to regulate cyabrB2 gene expression, with a high ON-OFF ratio up to approximately 50-fold. The transcription levels of several genes for which cyAbrB2 acts as a transcriptional upregulator were also decreased. Further, the cyAbrB2 expression-repressed mutant showed high glycogen accumulation, equivalent to that in the cyabrB2 deletion mutant (ΔcyabrB2). Phenotypic similarities between the cyabrB2 expression-repressed mutant and the ΔcyabrB2 mutant suggest that the riboregulator can potentially be used as a new chromosomal gene regulation tool in cyanobacteria.
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Affiliation(s)
- Kinuko Ueno
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Yuta Sakai
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Chika Shono
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Ippei Sakamoto
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Kaori Tsukakoshi
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Koji Sode
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Kazunori Ikebukuro
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.
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32
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Jeamton W, Dulsawat S, Tanticharoen M, Vonshak A, Cheevadhanarak S. Overcoming Intrinsic Restriction Enzyme Barriers Enhances Transformation Efficiency in Arthrospira platensis C1. PLANT & CELL PHYSIOLOGY 2017; 58:822-830. [PMID: 28158667 DOI: 10.1093/pcp/pcx016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 01/23/2017] [Indexed: 06/06/2023]
Abstract
The development of a reliable genetic transformation system for Arthrospira platensis has been a long-term goal, mainly for those trying either to improve its performance in large-scale cultivation systems or to enhance its value as food and feed additives. However, so far, most of the attempts to develop such a transformation system have had limited success. In this study, an efficient and stable transformation system for A. platensis C1 was successfully developed. Based on electroporation and transposon techniques, exogenous DNA could be transferred to and stably maintained in the A. platensis C1 genome. Most strains of Arthrospira possess strong restriction barriers, hampering the development of a gene transfer system for this group of cyanobacteria. By using a type I restriction inhibitor and liposomes to protect the DNA from nuclease digestion, the transformation efficiency was significantly improved. The transformants were able to grow on a selective medium for more than eight passages, and the transformed DNA could be detected from the stable transformants. We propose that the intrinsic endonuclease enzymes, particularly the type I restriction enzyme, in A. platensis C1 play an important role in the transformation efficiency of this industrial important cyanobacterium.
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Affiliation(s)
- Wattana Jeamton
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (Bang Khun Thian), Bangkok, Thailand
| | - Sudarat Dulsawat
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (Bang Khun Thian), Bangkok, Thailand
| | - Morakot Tanticharoen
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (Bang Khun Thian), Bangkok, Thailand
| | - Avigad Vonshak
- The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer campus, Israel
| | - Supapon Cheevadhanarak
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (Bang Khun Thian), Bangkok, Thailand
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (Bang Khun Thian), Bangkok, Thailand
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Immethun CM, DeLorenzo DM, Focht CM, Gupta D, Johnson CB, Moon TS. Physical, chemical, and metabolic state sensors expand the synthetic biology toolbox for Synechocystis sp. PCC 6803. Biotechnol Bioeng 2017; 114:1561-1569. [PMID: 28244586 DOI: 10.1002/bit.26275] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/19/2017] [Accepted: 02/19/2017] [Indexed: 02/04/2023]
Abstract
Many under-developed organisms possess important traits that can boost the effectiveness and sustainability of microbial biotechnology. Photoautotrophic cyanobacteria can utilize the energy captured from light to fix carbon dioxide for their metabolic needs while living in environments not suited for growing crops. Various value-added compounds have been produced by cyanobacteria in the laboratory; yet, the products' titers and yields are often not industrially relevant and lag behind what have been accomplished in heterotrophic microbes. Genetic tools for biological process control are needed to take advantage of cyanobacteria's beneficial qualities, as tool development also lags behind what has been created in common heterotrophic hosts. To address this problem, we developed a suite of sensors that regulate transcription in the model cyanobacterium Synechocystis sp. PCC 6803 in response to metabolically relevant signals, including light and the cell's nitrogen status, and a family of sensors that respond to the inexpensive chemical, l-arabinose. Increasing the number of available tools enables more complex and precise control of gene expression. Expanding the synthetic biology toolbox for this cyanobacterium also improves our ability to utilize this important under-developed organism in biotechnology. Biotechnol. Bioeng. 2017;114: 1561-1569. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Cheryl M Immethun
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Drew M DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Caroline M Focht
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Dinesh Gupta
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Charles B Johnson
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
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34
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Phelan RM, Sachs D, Petkiewicz SJ, Barajas JF, Blake-Hedges JM, Thompson MG, Reider Apel A, Rasor BJ, Katz L, Keasling JD. Development of Next Generation Synthetic Biology Tools for Use in Streptomyces venezuelae. ACS Synth Biol 2017; 6:159-166. [PMID: 27605473 DOI: 10.1021/acssynbio.6b00202] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Streptomyces have a rich history as producers of important natural products and this genus of bacteria has recently garnered attention for its potential applications in the broader context of synthetic biology. However, the dearth of genetic tools available to control and monitor protein production precludes rapid and predictable metabolic engineering that is possible in hosts such as Escherichia coli or Saccharomyces cerevisiae. In an effort to improve genetic tools for Streptomyces venezuelae, we developed a suite of standardized, orthogonal integration vectors and an improved method to monitor protein production in this host. These tools were applied to characterize heterologous promoters and various attB chromosomal integration sites. A final study leveraged the characterized toolset to demonstrate its use in producing the biofuel precursor bisabolene using a chromosomally integrated expression system. These tools advance S. venezuelae to be a practical host for future metabolic engineering efforts.
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Affiliation(s)
- Ryan M. Phelan
- Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
| | - Daniel Sachs
- Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
| | - Shayne J. Petkiewicz
- Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
| | - Jesus F. Barajas
- Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
| | | | | | - Amanda Reider Apel
- Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
| | - Blake J. Rasor
- Department
of Biology, Miami University, 212 Pearson Hall, Oxford, Ohio 45046, United States
| | | | - Jay D. Keasling
- Joint Bioenergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
- Novo
Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé, DK2970-Hørsholm, Denmark
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35
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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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36
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Huang CH, Shen CR, Li H, Sung LY, Wu MY, Hu YC. CRISPR interference (CRISPRi) for gene regulation and succinate production in cyanobacterium S. elongatus PCC 7942. Microb Cell Fact 2016; 15:196. [PMID: 27846887 PMCID: PMC5111286 DOI: 10.1186/s12934-016-0595-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 11/06/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Cyanobacterium Synechococcus elongatus PCC 7942 holds promise for biochemical conversion, but gene deletion in PCC 7942 is time-consuming and may be lethal to cells. CRISPR interference (CRISPRi) is an emerging technology that exploits the catalytically inactive Cas9 (dCas9) and single guide RNA (sgRNA) to repress sequence-specific genes without the need of gene knockout, and is repurposed to rewire metabolic networks in various procaryotic cells. RESULTS To employ CRISPRi for the manipulation of gene network in PCC 7942, we integrated the cassettes expressing enhanced yellow fluorescent protein (EYFP), dCas9 and sgRNA targeting different regions on eyfp into the PCC 7942 chromosome. Co-expression of dCas9 and sgRNA conferred effective and stable suppression of EYFP production at efficiencies exceeding 99%, without impairing cell growth. We next integrated the dCas9 and sgRNA targeting endogenous genes essential for glycogen accumulation (glgc) and succinate conversion to fumarate (sdhA and sdhB). Transcription levels of glgc, sdhA and sdhB were effectively suppressed with efficiencies depending on the sgRNA binding site. Targeted suppression of glgc reduced the expression to 6.2%, attenuated the glycogen accumulation to 4.8% and significantly enhanced the succinate titer. Targeting sdhA or sdhB also effectively downregulated the gene expression and enhanced the succinate titer ≈12.5-fold to ≈0.58-0.63 mg/L. CONCLUSIONS These data demonstrated that CRISPRi-mediated gene suppression allowed for re-directing the cellular carbon flow, thus paving a new avenue to rationally fine-tune the metabolic pathways in PCC 7942 for the production of biotechnological products.
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Affiliation(s)
- Chun-Hung Huang
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Claire R Shen
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Hung Li
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Li-Yu Sung
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Meng-Ying Wu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Yu-Chen Hu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan.
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37
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Li H, Shen CR, Huang CH, Sung LY, Wu MY, Hu YC. CRISPR-Cas9 for the genome engineering of cyanobacteria and succinate production. Metab Eng 2016; 38:293-302. [DOI: 10.1016/j.ymben.2016.09.006] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 08/03/2016] [Accepted: 09/27/2016] [Indexed: 10/20/2022]
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38
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Yang YT, Wang CY. Review of Microfluidic Photobioreactor Technology for Metabolic Engineering and Synthetic Biology of Cyanobacteria and Microalgae. MICROMACHINES 2016; 7:mi7100185. [PMID: 30404358 PMCID: PMC6190437 DOI: 10.3390/mi7100185] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/16/2016] [Accepted: 08/16/2016] [Indexed: 12/20/2022]
Abstract
One goal of metabolic engineering and synthetic biology for cyanobacteria and microalgae is to engineer strains that can optimally produce biofuels and commodity chemicals. However, the current workflow is slow and labor intensive with respect to assembly of genetic parts and characterization of production yields because of the slow growth rates of these organisms. Here, we review recent progress in the microfluidic photobioreactors and identify opportunities and unmet needs in metabolic engineering and synthetic biology. Because of the unprecedented experimental resolution down to the single cell level, long-term real-time monitoring capability, and high throughput with low cost, microfluidic photobioreactor technology will be an indispensible tool to speed up the development process, advance fundamental knowledge, and realize the full potential of metabolic engineering and synthetic biology for cyanobacteria and microalgae.
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Affiliation(s)
- Ya-Tang Yang
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Chun Ying Wang
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
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39
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Claassens NJ, Sousa DZ, dos Santos VAPM, de Vos WM, van der Oost J. Harnessing the power of microbial autotrophy. Nat Rev Microbiol 2016; 14:692-706. [DOI: 10.1038/nrmicro.2016.130] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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40
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Johnson TJ, Gibbons JL, Gu L, Zhou R, Gibbons WR. Molecular genetic improvements of cyanobacteria to enhance the industrial potential of the microbe: A review. Biotechnol Prog 2016; 32:1357-1371. [DOI: 10.1002/btpr.2358] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/30/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Tylor J. Johnson
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
- Dept. of MicrobiologyThe University of TennesseeKnoxville TN37996
| | - Jaimie L. Gibbons
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - Liping Gu
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - Ruanbao Zhou
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - William R. Gibbons
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
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41
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Yao L, Cengic I, Anfelt J, Hudson EP. Multiple Gene Repression in Cyanobacteria Using CRISPRi. ACS Synth Biol 2016; 5:207-12. [PMID: 26689101 DOI: 10.1021/acssynbio.5b00264] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We describe the application of clustered regularly interspaced short palindromic repeats interference (CRISPRi) for gene repression in the model cyanobacterium Synechcocystis sp. PCC 6803. The nuclease-deficient Cas9 from the type-II CRISPR/Cas of Streptrococcus pyogenes was used to repress green fluorescent protein (GFP) to negligible levels. CRISPRi was also used to repress formation of carbon storage compounds polyhydroxybutryate (PHB) and glycogen during nitrogen starvation. As an example of the potential of CRISPRi for basic and applied cyanobacteria research, we simultaneously knocked down 4 putative aldehyde reductases and dehydrogenases at 50-95% repression. This work also demonstrates that tightly repressed promoters allow for inducible and reversible CRISPRi in cyanobacteria.
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Affiliation(s)
- Lun Yao
- KTH—Royal Institute of Technology, Division of Proteomics and Nanobiotechnology, Science for Life Laboratory, Stockholm SE-171 21 Sweden
| | - Ivana Cengic
- KTH—Royal Institute of Technology, Division of Proteomics and Nanobiotechnology, Science for Life Laboratory, Stockholm SE-171 21 Sweden
| | - Josefine Anfelt
- KTH—Royal Institute of Technology, Division of Proteomics and Nanobiotechnology, Science for Life Laboratory, Stockholm SE-171 21 Sweden
| | - Elton P. Hudson
- KTH—Royal Institute of Technology, Division of Proteomics and Nanobiotechnology, Science for Life Laboratory, Stockholm SE-171 21 Sweden
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42
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Klanchui A, Raethong N, Prommeenate P, Vongsangnak W, Meechai A. Cyanobacterial Biofuels: Strategies and Developments on Network and Modeling. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 160:75-102. [PMID: 27783135 DOI: 10.1007/10_2016_42] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cyanobacteria, the phototrophic microorganisms, have attracted much attention recently as a promising source for environmentally sustainable biofuels production. However, barriers for commercial markets of cyanobacteria-based biofuels concern the economic feasibility. Miscellaneous strategies for improving the production performance of cyanobacteria have thus been developed. Among these, the simple ad hoc strategies resulting in failure to optimize fully cell growth coupled with desired product yield are explored. With the advancement of genomics and systems biology, a new paradigm toward systems metabolic engineering has been recognized. In particular, a genome-scale metabolic network reconstruction and modeling is a crucial systems-based tool for whole-cell-wide investigation and prediction. In this review, the cyanobacterial genome-scale metabolic models, which offer a system-level understanding of cyanobacterial metabolism, are described. The main process of metabolic network reconstruction and modeling of cyanobacteria are summarized. Strategies and developments on genome-scale network and modeling through the systems metabolic engineering approach are advanced and employed for efficient cyanobacterial-based biofuels production.
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Affiliation(s)
- Amornpan Klanchui
- Biological Engineering Program, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand
| | - Nachon Raethong
- Interdisciplinary Graduate Program in Bioscience, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Peerada Prommeenate
- Biochemical Engineering and Pilot Plant Research and Development (BEC) Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Wanwipa Vongsangnak
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.,Computational Biomodelling Laboratory for Agricultural Science and Technology (CBLAST), Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand
| | - Asawin Meechai
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
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43
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Rühle T, Leister D. Photosystem II Assembly from Scratch. FRONTIERS IN PLANT SCIENCE 2015; 6:1234. [PMID: 26793213 PMCID: PMC4709462 DOI: 10.3389/fpls.2015.01234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/19/2015] [Indexed: 05/06/2023]
Affiliation(s)
- Thilo Rühle
- Plant Molecular Biology, Department of Biology, Ludwig-Maximilians-University MunichMunich, Germany
| | - Dario Leister
- Plant Molecular Biology, Department of Biology, Ludwig-Maximilians-University MunichMunich, Germany
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of CopenhagenCopenhagen, Denmark
- *Correspondence: Dario Leister
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