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Deneer A, Fleck C. Mathematical Modelling in Plant Synthetic Biology. Methods Mol Biol 2022; 2379:209-251. [PMID: 35188665 DOI: 10.1007/978-1-0716-1791-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mathematical modelling techniques are integral to current research in plant synthetic biology. Modelling approaches can provide mechanistic understanding of a system, allowing predictions of behaviour and thus providing a tool to help design and analyse biological circuits. In this chapter, we provide an overview of mathematical modelling methods and their significance for plant synthetic biology. Starting with the basics of dynamics, we describe the process of constructing a model over both temporal and spatial scales and highlight crucial approaches, such as stochastic modelling and model-based design. Next, we focus on the model parameters and the techniques required in parameter analysis. We then describe the process of selecting a model based on tests and criteria and proceed to methods that allow closer analysis of the system's behaviour. Finally, we highlight the importance of uncertainty in modelling approaches and how to deal with a lack of knowledge, noisy data, and biological variability; all aspects that play a crucial role in the cooperation between the experimental and modelling components. Overall, this chapter aims to illustrate the importance of mathematical modelling in plant synthetic biology, providing an introduction for those researchers who are working with or working on modelling techniques.
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Affiliation(s)
- Anna Deneer
- Biometris, Department of Mathematical and Statistical Methods, Wageningen University, Wageningen, The Netherlands
| | - Christian Fleck
- ETH Zurich, Department of Biosystems Science and Engineering, Basel, Switzerland.
- Freiburg Institute for Data Analysis and Mathematical Modelling, University of Freiburg, Freiburg im Breisgau, Germany.
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2
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Wu W, Long MR, Zhang X, Reed JL, Maravelias CT. A framework for the identification of promising bio‐based chemicals. Biotechnol Bioeng 2018; 115:2328-2340. [DOI: 10.1002/bit.26779] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/18/2018] [Accepted: 06/18/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Wenzhao Wu
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center University of Wisconsin‐Madison Madison Wisconsin
| | - Matthew R. Long
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center University of Wisconsin‐Madison Madison Wisconsin
| | - Xiaolin Zhang
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center University of Wisconsin‐Madison Madison Wisconsin
| | - Jennifer L. Reed
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center University of Wisconsin‐Madison Madison Wisconsin
| | - Christos T. Maravelias
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center University of Wisconsin‐Madison Madison Wisconsin
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3
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Dolinšek J, Goldschmidt F, Johnson DR. Synthetic microbial ecology and the dynamic interplay between microbial genotypes. FEMS Microbiol Rev 2018; 40:961-979. [PMID: 28201744 DOI: 10.1093/femsre/fuw024] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/27/2016] [Accepted: 07/04/2016] [Indexed: 01/27/2023] Open
Abstract
Assemblages of microbial genotypes growing together can display surprisingly complex and unexpected dynamics and result in community-level functions and behaviors that are not readily expected from analyzing each genotype in isolation. This complexity has, at least in part, inspired a discipline of synthetic microbial ecology. Synthetic microbial ecology focuses on designing, building and analyzing the dynamic behavior of ‘ecological circuits’ (i.e. a set of interacting microbial genotypes) and understanding how community-level properties emerge as a consequence of those interactions. In this review, we discuss typical objectives of synthetic microbial ecology and the main advantages and rationales of using synthetic microbial assemblages. We then summarize recent findings of current synthetic microbial ecology investigations. In particular, we focus on the causes and consequences of the interplay between different microbial genotypes and illustrate how simple interactions can create complex dynamics and promote unexpected community-level properties. We finally propose that distinguishing between active and passive interactions and accounting for the pervasiveness of competition can improve existing frameworks for designing and predicting the dynamics of microbial assemblages.
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Affiliation(s)
- Jan Dolinšek
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Felix Goldschmidt
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - David R Johnson
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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4
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A set of synthetic versatile genetic control elements for the efficient expression of genes in Actinobacteria. Sci Rep 2018; 8:491. [PMID: 29323285 PMCID: PMC5765039 DOI: 10.1038/s41598-017-18846-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/18/2017] [Indexed: 12/22/2022] Open
Abstract
The design and engineering of secondary metabolite gene clusters that are characterized by complicated genetic organization, require the development of collections of well-characterized genetic control elements that can be reused reliably. Although a few intrinsic terminators and RBSs are used routinely, their translation and termination efficiencies have not been systematically studied in Actinobacteria. Here, we analyzed the influence of the regions surrounding RBSs on gene expression in these bacteria. We demonstrated that inappropriate RBSs can reduce the expression efficiency of a gene to zero. We developed a genetic device – an in vivo RBS-selector – that allows selection of an optimal RBS for any gene of interest, enabling rational control of the protein expression level. In addition, a genetic tool that provides the opportunity for measurement of termination efficiency was developed. Using this tool, we found strong terminators that lead to a 17–100-fold reduction in downstream expression and are characterized by sufficient sequence diversity to reduce homologous recombination when used with other elements. For the first time, a C-terminal degradation tag was employed for the control of protein stability in Streptomyces. Finally, we describe a collection of regulatory elements that can be used to control metabolic pathways in Actinobacteria.
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Wu W, Maravelias CT. Synthesis and techno-economic assessment of microbial-based processes for terpenes production. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:294. [PMID: 30386431 PMCID: PMC6203976 DOI: 10.1186/s13068-018-1285-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 10/09/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Recent advances in metabolic engineering enable the production of chemicals from sugars through microbial bio-conversion. Terpenes have attracted substantial attention due to their relatively high prices and wide applications in different industries. To this end, we synthesize and assess processes for microbial production of terpenes. RESULTS To explain a counterintuitive experimental phenomenon where terpenes such as limonene (normal boiling point 176 °C) are often found to be 100% present in the vapor phase after bio-conversion (operating at only ~ 30 °C), we first analyze the vapor-liquid equilibrium for systems containing terpenes. Then, we propose alternative production configurations, which are further studied, using limonene as an example, in several case studies. Next, we perform economic assessment of the alternative processes and identify the major cost components. Finally, we extend the assessment to account for different process parameters, terpene products, ways to address terpene toxicity (microbial engineering vs. solvent use), and cellulosic biomass as a feedstock. We identify the key cost drivers to be (1) feed glucose concentration (wt%), (2) product yield (% of maximum theoretical yield) and (3) VVM (Volume of air per Volume of broth liquid per Minute, i.e., aeration rate in min-1). The production of limonene, based on current experimental data, is found to be economically infeasible (production cost ~ 465 $/kg vs. market selling price ~ 7 $/kg), but higher glucose concentration and yield can lower the cost. Among 12 terpenes studied, limonene appears to be the most reasonable short-term target because of its large market size (~ 160 million $/year in the US) and the relatively easier to achieve break-even yield (~ 30%, assuming a 14 wt% feed glucose concentration and 0.1 min-1 VVM). CONCLUSIONS The methods proposed in this work are applicable to a range of terpenes as well as other extracellular insoluble chemicals with density lower than that of water, such as fatty acids. The results provide guidance for future research in metabolic engineering toward terpenes production in terms of setting targets for key design parameters.
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Affiliation(s)
- Wenzhao Wu
- Dept. of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706 USA
| | - Christos T. Maravelias
- Dept. of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706 USA
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6
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Mısırlı G, Hallinan J, Pocock M, Lord P, McLaughlin JA, Sauro H, Wipat A. Data Integration and Mining for Synthetic Biology Design. ACS Synth Biol 2016; 5:1086-1097. [PMID: 27110921 DOI: 10.1021/acssynbio.5b00295] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
One aim of synthetic biologists is to create novel and predictable biological systems from simpler modular parts. This approach is currently hampered by a lack of well-defined and characterized parts and devices. However, there is a wealth of existing biological information, which can be used to identify and characterize biological parts, and their design constraints in the literature and numerous biological databases. However, this information is spread among these databases in many different formats. New computational approaches are required to make this information available in an integrated format that is more amenable to data mining. A tried and tested approach to this problem is to map disparate data sources into a single data set, with common syntax and semantics, to produce a data warehouse or knowledge base. Ontologies have been used extensively in the life sciences, providing this common syntax and semantics as a model for a given biological domain, in a fashion that is amenable to computational analysis and reasoning. Here, we present an ontology for applications in synthetic biology design, SyBiOnt, which facilitates the modeling of information about biological parts and their relationships. SyBiOnt was used to create the SyBiOntKB knowledge base, incorporating and building upon existing life sciences ontologies and standards. The reasoning capabilities of ontologies were then applied to automate the mining of biological parts from this knowledge base. We propose that this approach will be useful to speed up synthetic biology design and ultimately help facilitate the automation of the biological engineering life cycle.
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Affiliation(s)
- Göksel Mısırlı
- School
of Computing Science, Newcastle University, NE1 7RU Newcastle
upon Tyne, United Kingdom
| | - Jennifer Hallinan
- School
of Computing Science, Newcastle University, NE1 7RU Newcastle
upon Tyne, United Kingdom
| | - Matthew Pocock
- School
of Computing Science, Newcastle University, NE1 7RU Newcastle
upon Tyne, United Kingdom
- Turing Ate My Hamster Ltd, NE27
0RT Newcastle upon Tyne, United Kingdom
| | - Phillip Lord
- School
of Computing Science, Newcastle University, NE1 7RU Newcastle
upon Tyne, United Kingdom
| | | | - Herbert Sauro
- Department
of Bioengineering, University of Washington, Seattle, Washington 98105, United States
| | - Anil Wipat
- School
of Computing Science, Newcastle University, NE1 7RU Newcastle
upon Tyne, United Kingdom
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7
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Pandey RP, Parajuli P, Koffas MA, Sohng JK. Microbial production of natural and non-natural flavonoids: Pathway engineering, directed evolution and systems/synthetic biology. Biotechnol Adv 2016; 34:634-662. [DOI: 10.1016/j.biotechadv.2016.02.012] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 02/24/2016] [Accepted: 02/29/2016] [Indexed: 12/18/2022]
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8
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Torres NV, Santos G. The (Mathematical) Modeling Process in Biosciences. Front Genet 2015; 6:354. [PMID: 26734063 PMCID: PMC4686688 DOI: 10.3389/fgene.2015.00354] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/07/2015] [Indexed: 11/13/2022] Open
Abstract
In this communication, we introduce a general framework and discussion on the role of models and the modeling process in the field of biosciences. The objective is to sum up the common procedures during the formalization and analysis of a biological problem from the perspective of Systems Biology, which approaches the study of biological systems as a whole. We begin by presenting the definitions of (biological) system and model. Particular attention is given to the meaning of mathematical model within the context of biology. Then, we present the process of modeling and analysis of biological systems. Three stages are described in detail: conceptualization of the biological system into a model, mathematical formalization of the previous conceptual model and optimization and system management derived from the analysis of the mathematical model. All along this work the main features and shortcomings of the process are analyzed and a set of rules that could help in the task of modeling any biological system are presented. Special regard is given to the formative requirements and the interdisciplinary nature of this approach. We conclude with some general considerations on the challenges that modeling is posing to current biology.
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Affiliation(s)
- Nestor V Torres
- Systems Biology and Mathematical Modelling Group, Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Sección de Biología de la Facultad de Ciencias, Universidad de La LagunaSan Cristóbal de La Laguna, Spain; Instituto de Tecnología Biomédica, CIBICANSan Cristóbal de La Laguna, Spain
| | - Guido Santos
- Systems Biology and Mathematical Modelling Group, Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Sección de Biología de la Facultad de Ciencias, Universidad de La LagunaSan Cristóbal de La Laguna, Spain; Instituto de Tecnología Biomédica, CIBICANSan Cristóbal de La Laguna, Spain
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9
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de la Escosura A, Briones C, Ruiz-Mirazo K. The systems perspective at the crossroads between chemistry and biology. J Theor Biol 2015; 381:11-22. [DOI: 10.1016/j.jtbi.2015.04.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/26/2015] [Indexed: 01/21/2023]
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10
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Affiliation(s)
- Kristin Hagen
- EA European Academy of Technology and Innovation Assessment GmbH, Bad Neuenahr-Ahrweiler, Germany
| | - Margret Engelhard
- EA European Academy of Technology and Innovation Assessment GmbH, Bad Neuenahr-Ahrweiler, Germany
| | - Georg Toepfer
- Center for Literary and Cultural Research Berlin, Berlin, Germany
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11
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Herrmann A. Dynamic combinatorial/covalent chemistry: a tool to read, generate and modulate the bioactivity of compounds and compound mixtures. Chem Soc Rev 2014; 43:1899-933. [PMID: 24296754 DOI: 10.1039/c3cs60336a] [Citation(s) in RCA: 277] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Reversible covalent bond formation under thermodynamic control adds reactivity to self-assembled supramolecular systems, and is therefore an ideal tool to assess complexity of chemical and biological systems. Dynamic combinatorial/covalent chemistry (DCC) has been used to read structural information by selectively assembling receptors with the optimum molecular fit around a given template from a mixture of reversibly reacting building blocks. This technique allows access to efficient sensing devices and the generation of new biomolecules, such as small molecule receptor binders for drug discovery, but also larger biomimetic polymers and macromolecules with particular three-dimensional structural architectures. Adding a kinetic factor to a thermodynamically controlled equilibrium results in dynamic resolution and in self-sorting and self-replicating systems, all of which are of major importance in biological systems. Furthermore, the temporary modification of bioactive compounds by reversible combinatorial/covalent derivatisation allows control of their release and facilitates their transport across amphiphilic self-assembled systems such as artificial membranes or cell walls. The goal of this review is to give a conceptual overview of how the impact of DCC on supramolecular assemblies at different levels can allow us to understand, predict and modulate the complexity of biological systems.
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Affiliation(s)
- Andreas Herrmann
- Firmenich SA, Division Recherche et Développement, Route des Jeunes 1, B. P. 239, CH-1211 Genève 8, Switzerland.
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12
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Copeland MF, Politz MC, Pfleger BF. Application of TALEs, CRISPR/Cas and sRNAs as trans-acting regulators in prokaryotes. Curr Opin Biotechnol 2014; 29:46-54. [PMID: 24632195 PMCID: PMC4162867 DOI: 10.1016/j.copbio.2014.02.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/28/2014] [Accepted: 02/13/2014] [Indexed: 01/09/2023]
Abstract
The last several years have witnessed an explosion in the understanding and use of novel, versatile trans-acting elements. TALEs, CRISPR/Cas, and sRNAs can be easily fashioned to bind any specific sequence of DNA (TALEs, CRISPR/Cas) or RNA (sRNAs) because of the simple rules governing their interactions with nucleic acids. This unique property enables these tools to repress the expression of genes at the transcriptional or post-transcriptional levels, respectively, without prior manipulation of cis-acting and/or chromosomal target DNA sequences. These tools are now being harnessed by synthetic biologists, particularly those in the eukaryotic community, for genome-wide regulation, editing, or epigenetic studies. Here we discuss the exciting opportunities for using TALEs, CRISPR/Cas, and sRNAs as synthetic trans-acting regulators in prokaryotes.
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Affiliation(s)
- Matthew F Copeland
- University of Wisconsin-Madison, Department of Chemical and Biological Engineering, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Mark C Politz
- University of Wisconsin-Madison, Department of Chemical and Biological Engineering, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Brian F Pfleger
- University of Wisconsin-Madison, Department of Chemical and Biological Engineering, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA.
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13
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A targeted proteomics toolkit for high-throughput absolute quantification of Escherichia coli proteins. Metab Eng 2014; 26:48-56. [PMID: 25205128 DOI: 10.1016/j.ymben.2014.08.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/06/2014] [Accepted: 08/28/2014] [Indexed: 11/20/2022]
Abstract
Transformation of engineered Escherichia coli into a robust microbial factory is contingent on precise control of metabolism. Yet, the throughput of omics technologies used to characterize cell components has lagged far behind our ability to engineer novel strains. To expand the utility of quantitative proteomics for metabolic engineering, we validated and optimized targeted proteomics methods for over 400 proteins from more than 20 major pathways in E. coli metabolism. Complementing these methods, we constructed a series of synthetic genes to produce concatenated peptides (QconCAT) for absolute quantification of the proteins and made them available through the Addgene plasmid repository (www.addgene.org). To facilitate high sample throughput, we developed a fast, analytical-flow chromatography method using a 5.5-min gradient (10 min total run time). Overall this toolkit provides an invaluable resource for metabolic engineering by increasing sample throughput, minimizing development time and providing peptide standards for absolute quantification of E. coli proteins.
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14
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Schrewe M, Julsing MK, Bühler B, Schmid A. Whole-cell biocatalysis for selective and productive C-O functional group introduction and modification. Chem Soc Rev 2014; 42:6346-77. [PMID: 23475180 DOI: 10.1039/c3cs60011d] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During the last decades, biocatalysis became of increasing importance for chemical and pharmaceutical industries. Regarding regio- and stereospecificity, enzymes have shown to be superior compared to traditional chemical synthesis approaches, especially in C-O functional group chemistry. Catalysts established on a process level are diverse and can be classified along a functional continuum starting with single-step biotransformations using isolated enzymes or microbial strains towards fermentative processes with recombinant microorganisms containing artificial synthetic pathways. The complex organization of respective enzymes combined with aspects such as cofactor dependency and low stability in isolated form often favors the use of whole cells over that of isolated enzymes. Based on an inventory of the large spectrum of biocatalytic C-O functional group chemistry, this review focuses on highlighting the potentials, limitations, and solutions offered by the application of self-regenerating microbial cells as biocatalysts. Different cellular functionalities are discussed in the light of their (possible) contribution to catalyst efficiency. The combined achievements in the areas of protein, genetic, metabolic, and reaction engineering enable the development of whole-cell biocatalysts as powerful tools in organic synthesis.
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Affiliation(s)
- Manfred Schrewe
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227 Dortmund, Germany
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15
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Frontiers of yeast metabolic engineering: diversifying beyond ethanol and Saccharomyces. Curr Opin Biotechnol 2013; 24:1023-30. [DOI: 10.1016/j.copbio.2013.03.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 03/05/2013] [Accepted: 03/07/2013] [Indexed: 01/09/2023]
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16
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Trosset JY, Carbonell P. Synergistic Synthetic Biology: Units in Concert. Front Bioeng Biotechnol 2013; 1:11. [PMID: 25022769 PMCID: PMC4090895 DOI: 10.3389/fbioe.2013.00011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/01/2013] [Indexed: 01/31/2023] Open
Abstract
Synthetic biology aims at translating the methods and strategies from engineering into biology in order to streamline the design and construction of biological devices through standardized parts. Modular synthetic biology devices are designed by means of an adequate elimination of cross-talk that makes circuits orthogonal and specific. To that end, synthetic constructs need to be adequately optimized through in silico modeling by choosing the right complement of genetic parts and by experimental tuning through directed evolution and craftsmanship. In this review, we consider an additional and complementary tool available to the synthetic biologist for innovative design and successful construction of desired circuit functionalities: biological synergies. Synergy is a prevalent emergent property in biological systems that arises from the concerted action of multiple factors producing an amplification or cancelation effect compared with individual actions alone. Synergies appear in domains as diverse as those involved in chemical and protein activity, polypharmacology, and metabolic pathway complementarity. In conventional synthetic biology designs, synergistic cross-talk between parts and modules is generally attenuated in order to verify their orthogonality. Synergistic interactions, however, can induce emergent behavior that might prove useful for synthetic biology applications, like in functional circuit design, multi-drug treatment, or in sensing and delivery devices. Synergistic design principles are therefore complementary to those coming from orthogonal design and may provide added value to synthetic biology applications. The appropriate modeling, characterization, and design of synergies between biological parts and units will allow the discovery of yet unforeseeable, novel synthetic biology applications.
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Affiliation(s)
| | - Pablo Carbonell
- BioRetroSynth Laboratory, Institute of Systems and Synthetic Biology, University of Evry-Val d'Essonne , Evry , France ; BioRetroSynth Laboratory, Institute of Systems and Synthetic Biology, CNRS , Evry , France
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17
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Abatemarco J, Hill A, Alper HS. Expanding the metabolic engineering toolbox with directed evolution. Biotechnol J 2013; 8:1397-410. [PMID: 23857895 DOI: 10.1002/biot.201300021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/10/2013] [Accepted: 06/24/2013] [Indexed: 01/02/2023]
Abstract
Cellular systems can be engineered into factories that produce high-value chemicals from renewable feedstock. Such an approach requires an expanded toolbox for metabolic engineering. Recently, protein engineering and directed evolution strategies have started to play a growing and critical role within metabolic engineering. This review focuses on the various ways in which directed evolution can be applied in conjunction with metabolic engineering to improve product yields. Specifically, we discuss the application of directed evolution on both catalytic and non-catalytic traits of enzymes, on regulatory elements, and on whole genomes in a metabolic engineering context. We demonstrate how the goals of metabolic pathway engineering can be achieved in part through evolving cellular parts as opposed to traditional approaches that rely on gene overexpression and deletion. Finally, we discuss the current limitations in screening technology that hinder the full implementation of a metabolic pathway-directed evolution approach.
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Affiliation(s)
- Joseph Abatemarco
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
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18
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Use of expression-enhancing terminators in Saccharomyces cerevisiae to increase mRNA half-life and improve gene expression control for metabolic engineering applications. Metab Eng 2013; 19:88-97. [PMID: 23856240 DOI: 10.1016/j.ymben.2013.07.001] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/12/2013] [Accepted: 07/03/2013] [Indexed: 01/24/2023]
Abstract
Control of gene and protein expression of both endogenous and heterologous genes is a key component of metabolic engineering. While a large amount of work has been published characterizing promoters for this purpose, less effort has been exerted to elucidate the role of terminators in yeast. In this study, we characterize over 30 terminators for use in metabolic engineering applications in Saccharomyces cerevisiae and determine mRNA half-life changes to be the major cause of the varied protein and transcript expression level. We demonstrate that the difference in transcript level can be over 6.5-fold even for high strength promoters. The influence of terminator selection is magnified when coupled with a low-expression promoter, with a maximum difference in protein expression of 11-fold between an expression-enhancing terminator and the parent plasmid terminator and over 35-fold difference when compared with a no-terminator baseline. This is the first time that terminators have been investigated in the context of multiple promoters spanning orders of magnitude in activity. Finally, we demonstrate the utility of terminator selection for metabolic engineering by using a mutant xylose isomerase gene as a proof-of-concept. Through pairing an expression-enhancing terminator with a low-expression promoter, we were able to achieve the same phenotypic result as with a promoter considerably higher in strength. Moreover, we can further boost the phenotype of the high-strength promoter by pairing it with an expression-enhancing terminator. This work highlights how terminator elements can be used to control metabolic pathways in the same way that promoters are traditionally used in yeast. Together, this work demonstrates that terminators will be an important part of heterologous gene expression and metabolic engineering for yeast in the future.
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19
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Kang J, Gu P, Wang Y, Li Y, Yang F, Wang Q, Qi Q. Engineering of an N-acetylneuraminic acid synthetic pathway in Escherichia coli. Metab Eng 2012; 14:623-9. [DOI: 10.1016/j.ymben.2012.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 08/27/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
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20
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Blazeck J, Alper HS. Promoter engineering: Recent advances in controlling transcription at the most fundamental level. Biotechnol J 2012; 8:46-58. [DOI: 10.1002/biot.201200120] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 06/25/2012] [Accepted: 07/17/2012] [Indexed: 12/25/2022]
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21
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Lanza AM, Blazeck JJ, Crook NC, Alper HS. Linking yeast Gcn5p catalytic function and gene regulation using a quantitative, graded dominant mutant approach. PLoS One 2012; 7:e36193. [PMID: 22558379 PMCID: PMC3338614 DOI: 10.1371/journal.pone.0036193] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 04/03/2012] [Indexed: 11/18/2022] Open
Abstract
Establishing causative links between protein functional domains and global gene regulation is critical for advancements in genetics, biotechnology, disease treatment, and systems biology. This task is challenging for multifunctional proteins when relying on traditional approaches such as gene deletions since they remove all domains simultaneously. Here, we describe a novel approach to extract quantitative, causative links by modulating the expression of a dominant mutant allele to create a function-specific competitive inhibition. Using the yeast histone acetyltransferase Gcn5p as a case study, we demonstrate the utility of this approach and (1) find evidence that Gcn5p is more involved in cell-wide gene repression, instead of the accepted gene activation associated with HATs, (2) identify previously unknown gene targets and interactions for Gcn5p-based acetylation, (3) quantify the strength of some Gcn5p-DNA associations, (4) demonstrate that this approach can be used to correctly identify canonical chromatin modifications, (5) establish the role of acetyltransferase activity on synthetic lethal interactions, and (6) identify new functional classes of genes regulated by Gcn5p acetyltransferase activity—all six of these major conclusions were unattainable by using standard gene knockout studies alone. We recommend that a graded dominant mutant approach be utilized in conjunction with a traditional knockout to study multifunctional proteins and generate higher-resolution data that more accurately probes protein domain function and influence.
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Affiliation(s)
- Amanda M. Lanza
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, United States of America
| | - John J. Blazeck
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, United States of America
| | - Nathan C. Crook
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, United States of America
| | - Hal S. Alper
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, United States of America
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
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22
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Alper HS. Converting cells into cellular factories. Comput Struct Biotechnol J 2012; 3:e201210001. [PMID: 24688661 PMCID: PMC3962202 DOI: 10.5936/csbj.201210001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 11/08/2012] [Indexed: 11/28/2022] Open
Affiliation(s)
- Hal S Alper
- Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712 ; Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX 78712
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