1
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Battaglino B, Du W, Pagliano C, Jongbloets JA, Re A, Saracco G, Branco dos Santos F. Channeling Anabolic Side Products toward the Production of Nonessential Metabolites: Stable Malate Production in Synechocystis sp. PCC6803. ACS Synth Biol 2021; 10:3518-3526. [PMID: 34808039 PMCID: PMC8689693 DOI: 10.1021/acssynbio.1c00440] [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] [Indexed: 11/28/2022]
Abstract
Powered by (sun)light to oxidize water, cyanobacteria can directly convert atmospheric CO2 into valuable carbon-based compounds and meanwhile release O2 to the atmosphere. As such, cyanobacteria are promising candidates to be developed as microbial cell factories for the production of chemicals. Nevertheless, similar to other microbial cell factories, engineered cyanobacteria may suffer from production instability. The alignment of product formation with microbial fitness is a valid strategy to tackle this issue. We have described previously the "FRUITS" algorithm for the identification of metabolites suitable to be coupled to growth (i.e., side products in anabolic reactions) in the model cyanobacterium Synechocystis. sp PCC6803. However, the list of candidate metabolites identified using this algorithm can be somewhat limiting, due to the inherent structure of metabolic networks. Here, we aim at broadening the spectrum of candidate compounds beyond the ones predicted by FRUITS, through the conversion of a growth-coupled metabolite to downstream metabolites via thermodynamically favored conversions. We showcase the feasibility of this approach for malate production using fumarate as the growth-coupled substrate in Synechocystis mutants. A final titer of ∼1.2 mM was achieved for malate during photoautotrophic batch cultivations. Under prolonged continuous cultivation, the most efficient malate-producing strain can maintain its productivity for at least 45 generations, sharply contrasting with other producing Synechocystis strains engineered with classical approaches. Our study also opens a new possibility for extending the stable production concept to derivatives of growth-coupled metabolites, increasing the list of suitable target compounds.
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Affiliation(s)
- Beatrice Battaglino
- Applied Science and Technology Department, BioSolar Lab, Politecnico di Torino, Environment
Park, Via Livorno 60, 10144 Torino, Italy
- Centre for Sustainable Future Technologies, Istituto Italiano di Tecnologia, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Wei Du
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Cristina Pagliano
- Applied Science and Technology Department, BioSolar Lab, Politecnico di Torino, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Joeri A. Jongbloets
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Angela Re
- Centre for Sustainable Future Technologies, Istituto Italiano di Tecnologia, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Guido Saracco
- Applied Science and Technology Department, BioSolar Lab, Politecnico di Torino, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Filipe Branco dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
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2
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Taylor GM, Hitchcock A, Heap JT. Combinatorial assembly platform enabling engineering of genetically stable metabolic pathways in cyanobacteria. Nucleic Acids Res 2021; 49:e123. [PMID: 34554258 PMCID: PMC8643660 DOI: 10.1093/nar/gkab791] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/18/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are simple, efficient, genetically-tractable photosynthetic microorganisms which in principle represent ideal biocatalysts for CO2 capture and conversion. However, in practice, genetic instability and low productivity are key, linked problems in engineered cyanobacteria. We took a massively parallel approach, generating and characterising libraries of synthetic promoters and RBSs for the cyanobacterium Synechocystis sp. PCC 6803, and assembling a sparse combinatorial library of millions of metabolic pathway-encoding construct variants. Genetic instability was observed for some variants, which is expected when variants cause metabolic burden. Surprisingly however, in a single combinatorial round without iterative optimisation, 80% of variants chosen at random and cultured photoautotrophically over many generations accumulated the target terpenoid lycopene from atmospheric CO2, apparently overcoming genetic instability. This large-scale parallel metabolic engineering of cyanobacteria provides a new platform for development of genetically stable cyanobacterial biocatalysts for sustainable light-driven production of valuable products directly from CO2, avoiding fossil carbon or competition with food production.
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Affiliation(s)
- George M Taylor
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - John T Heap
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.,School of Life Sciences, The University of Nottingham, Biodiscovery Institute, University Park, Nottingham NG7 2RD, UK
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3
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Shabestary K, Hernández HP, Miao R, Ljungqvist E, Hallman O, Sporre E, Branco Dos Santos F, Hudson EP. Cycling between growth and production phases increases cyanobacteria bioproduction of lactate. Metab Eng 2021; 68:131-141. [PMID: 34601120 DOI: 10.1016/j.ymben.2021.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/03/2021] [Accepted: 09/25/2021] [Indexed: 01/23/2023]
Abstract
Decoupling growth from product synthesis is a promising strategy to increase carbon partitioning and maximize productivity in cell factories. However, reduction in both substrate uptake rate and metabolic activity in the production phase are an underlying problem for upscaling. Here, we used CRISPR interference to repress growth in lactate-producing Synechocystis sp. PCC 6803. Carbon partitioning to lactate in the production phase exceeded 90%, but CO2 uptake was severely reduced compared to uptake during the growth phase. We characterized strains during the onset of growth arrest using transcriptomics and proteomics. Multiple genes involved in ATP homeostasis were regulated once growth was inhibited, which suggests an alteration of energy charge that may lead to reduced substrate uptake. In order to overcome the reduced metabolic activity and take advantage of increased carbon partitioning, we tested a novel production strategy that involved alternating growth arrest and recovery by periodic addition of an inducer molecule to activate CRISPRi. Using this strategy, we maintained lactate biosynthesis in Synechocystis for 30 days in a constant light turbidostat cultivation. Cumulative lactate titers were also increased by 100% compared to a constant growth-arrest regime, and reached 1 g/L. Further, the cultivation produced lactate for 30 days, compared to 20 days for the non-growth arrest cultivation. Periodic growth arrest could be applicable for other products, and in cyanobacteria, could be linked to internal circadian rhythms that persist in constant light.
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Affiliation(s)
- Kiyan Shabestary
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Hugo Pineda Hernández
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Rui Miao
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Emil Ljungqvist
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Olivia Hallman
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Emil Sporre
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Filipe Branco Dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Elton P Hudson
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden.
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4
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Battaglino B, Arduino A, Pagliano C, Sforza E, Bertucco A. Optimization of Light and Nutrients Supply to Stabilize Long-Term Industrial Cultivation of Metabolically Engineered Cyanobacteria: A Model-Based Analysis. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c04887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Beatrice Battaglino
- BioSolar Lab, Applied Science and Technology Department, Politecnico di Torino, Environment Park, Via Livorno 60, 10144 Torino, Italy
| | - Alessandro Arduino
- Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy
| | - Cristina Pagliano
- BioSolar Lab, Applied Science and Technology Department, Politecnico di Torino, Environment Park, Via Livorno 60, 10144 Torino, Italy
| | - Eleonora Sforza
- Department of Industrial Engineering, Università di Padova, Via Marzolo 9, 35131 Padova, Italy
| | - Alberto Bertucco
- Department of Industrial Engineering, Università di Padova, Via Marzolo 9, 35131 Padova, Italy
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5
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Battaglino B, Arduino A, Pagliano C. Mathematical modeling for the design of evolution experiments to study the genetic instability of metabolically engineered photosynthetic microorganisms. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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Caicedo-Burbano P, Smit T, Pineda Hernández H, Du W, Branco dos Santos F. Construction of Fully Segregated Genomic Libraries in Polyploid Organisms Such as Synechocystis sp. PCC 6803. ACS Synth Biol 2020; 9:2632-2638. [PMID: 33017143 PMCID: PMC7573980 DOI: 10.1021/acssynbio.0c00353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Indexed: 12/11/2022]
Abstract
Several microbes are polyploid, meaning they contain several copies of their chromosome. Cyanobacteria, while holding great potential as photosynthetic cell factories of various products, are found among them. In these clades the diversity of genetic elements that serve within the basic molecular toolbox is often limiting. To assist mining for the latter, we present here a method for the generation of fully segregated genomic libraries, specifically designed for polyploids. We provide proof-of-principle for this method by generating a fully segregated genomic promoter library in the cyanobacterium Synechocystis sp. PCC 6803. This new tool was first analyzed through fluorescence activated cell sorting (FACS) and then a fraction was further characterized regarding promoter sequence. The location of libraries on the chromosome provides a better reflection of the behavior of its elements. Our work presents the first method for constructing fully segregated genomic libraries in polyploids, which may facilitate their usage in synthetic biology applications.
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Affiliation(s)
- Patricia Caicedo-Burbano
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Tycho Smit
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Hugo Pineda Hernández
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Wei Du
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Filipe Branco dos Santos
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
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7
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Cavaiuolo M, Chagneau C, Laalami S, Putzer H. Impact of RNase E and RNase J on Global mRNA Metabolism in the Cyanobacterium Synechocystis PCC6803. Front Microbiol 2020; 11:1055. [PMID: 32582060 PMCID: PMC7283877 DOI: 10.3389/fmicb.2020.01055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 04/29/2020] [Indexed: 01/18/2023] Open
Abstract
mRNA levels result from an equilibrium between transcription and degradation. Ribonucleases (RNases) facilitate the turnover of mRNA, which is an important way of controlling gene expression, allowing the cells to adjust transcript levels to a changing environment. In contrast to the heterotrophic model bacteria Escherichia coli and Bacillus subtilis, RNA decay has not been studied in detail in cyanobacteria. Synechocystis sp. PCC6803 encodes orthologs of both E. coli and B. subtilis RNases, including RNase E and RNase J, respectively. We show that in vitro Sy RNases E and J have an endonucleolytic cleavage specificity that is very similar between them and also compared to orthologous enzymes from E. coli, B. subtilis, and Chlamydomonas. Moreover, Sy RNase J displays a robust 5′-exoribonuclease activity similar to B. subtilis RNase J1, but unlike the evolutionarily related RNase J in chloroplasts. Both nucleases are essential and gene deletions could not be fully segregated in Synechocystis. We generated partially disrupted strains of Sy RNase E and J that were stable enough to allow for their growth and characterization. A transcriptome analysis of these strains partially depleted for RNases E and J, respectively, allowed to observe effects on specific transcripts. RNase E altered the expression of a larger number of chromosomal genes and antisense RNAs compared to RNase J, which rather affects endogenous plasmid encoded transcripts. Our results provide the first description of the main transcriptomic changes induced by the partial depletion of two essential ribonucleases in cyanobacteria.
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Affiliation(s)
- Marina Cavaiuolo
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Carine Chagneau
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Soumaya Laalami
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Harald Putzer
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
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8
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Du W, Jongbloets JA, Guillaume M, van de Putte B, Battaglino B, Hellingwerf KJ, Branco dos Santos F. Exploiting Day- and Night-Time Metabolism of Synechocystis sp. PCC 6803 for Fitness-Coupled Fumarate Production around the Clock. ACS Synth Biol 2019; 8:2263-2269. [PMID: 31553573 PMCID: PMC6804261 DOI: 10.1021/acssynbio.9b00289] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Indexed: 01/18/2023]
Abstract
Cyanobacterial cell factories are widely researched for the sustainable production of compounds directly from CO2. Their application, however, has been limited for two reasons. First, traditional approaches have been shown to lead to unstable cell factories that lose their production capability when scaled to industrial levels. Second, the alternative approaches developed so far are mostly limited to growing conditions, which are not always the case in industry, where nongrowth periods tend to occur (e.g., darkness). We tackled both by generalizing the concept of growth-coupled production to fitness coupling. The feasibility of this new approach is demonstrated for the production of fumarate by constructing the first stable dual-strategy cell factory. We exploited circadian metabolism using both systems and synthetic biology tools, resulting in the obligatorily coupling of fumarate to either biomass or energy production. Resorting to laboratory evolution experiments, we show that this engineering approach is more stable than conventional methods.
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Affiliation(s)
- Wei Du
- Molecular
Microbial Physiology Group, Faculty of Life Sciences, Swammerdam Institute
of Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Joeri A. Jongbloets
- Molecular
Microbial Physiology Group, Faculty of Life Sciences, Swammerdam Institute
of Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Max Guillaume
- Molecular
Microbial Physiology Group, Faculty of Life Sciences, Swammerdam Institute
of Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bram van de Putte
- Molecular
Microbial Physiology Group, Faculty of Life Sciences, Swammerdam Institute
of Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Beatrice Battaglino
- Applied
Science and Technology Department, Politecnico
di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
- Centre
for Sustainable Future Technologies, Istituto
Italiano di Tecnologia, Environment Park, Via Livorno 60, 10144 Torino, Italy
| | - Klaas J. Hellingwerf
- Molecular
Microbial Physiology Group, Faculty of Life Sciences, Swammerdam Institute
of Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Filipe Branco dos Santos
- Molecular
Microbial Physiology Group, Faculty of Life Sciences, Swammerdam Institute
of Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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9
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Pérez AA, Chen Q, Hernández HP, Branco dos Santos F, Hellingwerf KJ. On the use of oxygenic photosynthesis for the sustainable production of commodity chemicals. PHYSIOLOGIA PLANTARUM 2019; 166:413-427. [PMID: 30829400 PMCID: PMC6850307 DOI: 10.1111/ppl.12946] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 05/13/2023]
Abstract
A sustainable society will have to largely refrain from the use of fossil carbon deposits. In such a regime, renewable electricity can be harvested as a primary source of energy. However, as for the synthesis of carbon-based materials from bulk chemicals, an alternative is required. A sustainable approach towards this is the synthesis of commodity chemicals from CO2 , water and sunlight. Multiple paths to achieve this have been designed and tested in the domains of chemistry and biology. In the latter, the use of both chemotrophic and phototrophic organisms has been advocated. 'Direct conversion' of CO2 and H2 O, catalyzed by an oxyphototroph, has excellent prospects to become the most economically competitive of these transformations, because of the relative ease of scale-up of this process. Significantly, for a wide range of energy and commodity products, a proof of principle via engineering of the corresponding production organism has been provided. In the optimization of a cyanobacterial production organism, a wide range of aspects has to be addressed. Of these, here we will put our focus on: (1) optimizing the (carbon) flux to the desired product; (2) increasing the genetic stability of the producing organism and (3) maximizing its energy conversion efficiency. Significant advances have been made on all these three aspects during the past 2 years and these will be discussed: (1) increasing the carbon partitioning to >50%; (2) aligning product formation with the growth of the cells and (3) expanding the photosynthetically active radiation region for oxygenic photosynthesis.
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Affiliation(s)
- Adam A. Pérez
- Molecular Microbial Physiology GroupSwammerdam Institute for Life Sciences, University of Amsterdam1098 XH AmsterdamThe Netherlands
- Photanol BVMatrix VAmsterdam, 1098 XHThe Netherlands
| | - Que Chen
- Molecular Microbial Physiology GroupSwammerdam Institute for Life Sciences, University of Amsterdam1098 XH AmsterdamThe Netherlands
| | - Hugo Pineda Hernández
- Molecular Microbial Physiology GroupSwammerdam Institute for Life Sciences, University of Amsterdam1098 XH AmsterdamThe Netherlands
| | - Filipe Branco dos Santos
- Molecular Microbial Physiology GroupSwammerdam Institute for Life Sciences, University of Amsterdam1098 XH AmsterdamThe Netherlands
| | - Klaas J. Hellingwerf
- Molecular Microbial Physiology GroupSwammerdam Institute for Life Sciences, University of Amsterdam1098 XH AmsterdamThe Netherlands
- Photanol BVMatrix VAmsterdam, 1098 XHThe Netherlands
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10
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Betterle N, Melis A. Photosynthetic generation of heterologous terpenoids in cyanobacteria. Biotechnol Bioeng 2019; 116:2041-2051. [DOI: 10.1002/bit.26988] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/01/2019] [Accepted: 04/04/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Nico Betterle
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeley California
| | - Anastasios Melis
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeley California
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11
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Janasch M, Asplund-Samuelsson J, Steuer R, Hudson EP. Kinetic modeling of the Calvin cycle identifies flux control and stable metabolomes in Synechocystis carbon fixation. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:973-983. [PMID: 30371804 PMCID: PMC6363089 DOI: 10.1093/jxb/ery382] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/22/2018] [Indexed: 05/04/2023]
Abstract
Biological fixation of atmospheric CO2 via the Calvin-Benson-Bassham cycle has massive ecological impact and offers potential for industrial exploitation, either by improving carbon fixation in plants and autotrophic bacteria, or by installation into new hosts. A kinetic model of the Calvin-Benson-Bassham cycle embedded in the central carbon metabolism of the cyanobacterium Synechocystis sp. PCC 6803 was developed to investigate its stability and underlying control mechanisms. To reduce the uncertainty associated with a single parameter set, random sampling of the steady-state metabolite concentrations and the enzyme kinetic parameters was employed, resulting in millions of parameterized models which were analyzed for flux control and stability against perturbation. Our results show that the Calvin cycle had an overall high intrinsic stability, but a high concentration of ribulose 1,5-bisphosphate was associated with unstable states. Low substrate saturation and high product saturation of enzymes involved in highly interconnected reactions correlated with increased network stability. Flux control, that is the effect that a change in one reaction rate has on the other reactions in the network, was distributed and mostly exerted by energy supply (ATP), but also by cofactor supply (NADPH). Sedoheptulose 1,7-bisphosphatase/fructose 1,6-bisphosphatase, fructose-bisphosphate aldolase, and transketolase had a weak but positive effect on overall network flux, in agreement with published observations. The identified flux control and relationships between metabolite concentrations and system stability can guide metabolic engineering. The kinetic model structure and parameterizing framework can be expanded for analysis of metabolic systems beyond the Calvin cycle.
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Affiliation(s)
- Markus Janasch
- Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Solna, Sweden
| | - Johannes Asplund-Samuelsson
- Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Solna, Sweden
| | - Ralf Steuer
- Fachinstitut für Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Elton P Hudson
- Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Solna, Sweden
- Correspondence:
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12
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Yunus IS, Jones PR. Photosynthesis-dependent biosynthesis of medium chain-length fatty acids and alcohols. Metab Eng 2018; 49:59-68. [DOI: 10.1016/j.ymben.2018.07.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 12/27/2022]
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13
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Dexter J, Dziga D, Lv J, Zhu J, Strzalka W, Maksylewicz A, Maroszek M, Marek S, Fu P. Heterologous expression of mlrA in a photoautotrophic host - Engineering cyanobacteria to degrade microcystins. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:926-935. [PMID: 29454496 DOI: 10.1016/j.envpol.2018.01.071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/15/2018] [Accepted: 01/21/2018] [Indexed: 05/08/2023]
Abstract
In this report, we establish proof-of-principle demonstrating for the first time genetic engineering of a photoautotrophic microorganism for bioremediation of naturally occurring cyanotoxins. In model cyanobacterium Synechocystis sp. PCC 6803 we have heterologously expressed Sphingopyxis sp. USTB-05 microcystinase (MlrA) bearing a 23 amino acid N-terminus secretion peptide from native Synechocystis sp. PCC 6803 PilA (sll1694). The resultant whole cell biocatalyst displayed about 3 times higher activity against microcystin-LR compared to a native MlrA host (Sphingomonas sp. ACM 3962), normalized for optical density. In addition, MlrA activity was found to be almost entirely located in the cyanobacterial cytosolic fraction, despite the presence of the secretion tag, with crude cellular extracts showing MlrA activity comparable to extracts from MlrA expressing E. coli. Furthermore, despite approximately 9.4-fold higher initial MlrA activity of a whole cell E. coli biocatalyst, utilization of a photoautotrophic chassis resulted in prolonged stability of MlrA activity when cultured under semi-natural conditions (using lake water), with the heterologous MlrA biocatalytic activity of the E. coli culture disappearing after 4 days, while the cyanobacterial host displayed activity (3% of initial activity) after 9 days. In addition, the cyanobacterial cell density was maintained over the duration of this experiment while the cell density of the E. coli culture rapidly declined. Lastly, failure to establish a stable cyanobacterial isolate expressing native MlrA (without the N-terminus tag) via the strong cpcB560 promoter draws attention to the use of peptide tags to positively modulate expression of potentially toxic proteins.
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Affiliation(s)
- Jason Dexter
- College of Life Science and Technology, Beijing University of Chemical Technology, 15, Beisanhuan East Road, Chaoyang District, Beijing 100029, China; Cyanoworks, LLC, 1771 Haskell Rd., Olean, NY 14760, USA.
| | - Dariusz Dziga
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Jing Lv
- New Energy Research Center, China University of Petroleum (Beijing), 18 Fuxue Road, Changping District, Beijing 102249, China.
| | - Junqi Zhu
- College of Life Science and Technology, Beijing University of Chemical Technology, 15, Beisanhuan East Road, Chaoyang District, Beijing 100029, China.
| | - Wojciech Strzalka
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Anna Maksylewicz
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Magdalena Maroszek
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Sylwia Marek
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 31-007 Kraków, Poland.
| | - Pengcheng Fu
- College of Life Science and Technology, Beijing University of Chemical Technology, 15, Beisanhuan East Road, Chaoyang District, Beijing 100029, China.
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14
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Du W, Jongbloets JA, van Boxtel C, Pineda Hernández H, Lips D, Oliver BG, Hellingwerf KJ, Branco dos Santos F. Alignment of microbial fitness with engineered product formation: obligatory coupling between acetate production and photoautotrophic growth. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:38. [PMID: 29456625 PMCID: PMC5809919 DOI: 10.1186/s13068-018-1037-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 01/31/2018] [Indexed: 05/04/2023]
Abstract
BACKGROUND Microbial bioengineering has the potential to become a key contributor to the future development of human society by providing sustainable, novel, and cost-effective production pipelines. However, the sustained productivity of genetically engineered strains is often a challenge, as spontaneous non-producing mutants tend to grow faster and take over the population. Novel strategies to prevent this issue of strain instability are urgently needed. RESULTS In this study, we propose a novel strategy applicable to all microbial production systems for which a genome-scale metabolic model is available that aligns the production of native metabolites to the formation of biomass. Based on well-established constraint-based analysis techniques such as OptKnock and FVA, we developed an in silico pipeline-FRUITS-that specifically 'Finds Reactions Usable in Tapping Side-products'. It analyses a metabolic network to identify compounds produced in anabolism that are suitable to be coupled to growth by deletion of their re-utilization pathway(s), and computes their respective biomass and product formation rates. When applied to Synechocystis sp. PCC6803, a model cyanobacterium explored for sustainable bioproduction, a total of nine target metabolites were identified. We tested our approach for one of these compounds, acetate, which is used in a wide range of industrial applications. The model-guided engineered strain shows an obligatory coupling between acetate production and photoautotrophic growth as predicted. Furthermore, the stability of acetate productivity in this strain was confirmed by performing prolonged turbidostat cultivations. CONCLUSIONS This work demonstrates a novel approach to stabilize the production of target compounds in cyanobacteria that culminated in the first report of a photoautotrophic growth-coupled cell factory. The method developed is generic and can easily be extended to any other modeled microbial production system.
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Affiliation(s)
- Wei Du
- Molecular Microbial Physiology Group, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Joeri A. Jongbloets
- Molecular Microbial Physiology Group, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Coco van Boxtel
- Systems Bioinformatics/Amsterdam Institute for Molecules, Medicines and Systems (AIMMS)/Netherlands Institute for Systems Biology, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Hugo Pineda Hernández
- Molecular Microbial Physiology Group, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - David Lips
- Molecular Microbial Physiology Group, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Brett G. Oliver
- Systems Bioinformatics/Amsterdam Institute for Molecules, Medicines and Systems (AIMMS)/Netherlands Institute for Systems Biology, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
- Modelling of Biological Process, BioQuant, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Klaas J. Hellingwerf
- Molecular Microbial Physiology Group, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Filipe Branco dos Santos
- Molecular Microbial Physiology Group, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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15
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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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