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Ye C, Chen X, Yang M, Zeng X, Qiao S. CRISPR/Cas9 mediated T7 RNA polymerase gene knock-in in E. coli BW25113 makes T7 expression system work efficiently. J Biol Eng 2021; 15:22. [PMID: 34384456 PMCID: PMC8359068 DOI: 10.1186/s13036-021-00270-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/07/2021] [Indexed: 01/16/2023] Open
Abstract
T7 Expression System is a common method of ensuring tight control and high-level induced expression. However, this system can only work in some bacterial strains in which the T7 RNA Polymerase gene resides in the chromosome. In this study, we successfully introduced a chromosomal copy of the T7 RNA Polymerase gene under control of the lacUV5 promoter into Escherichia coli BW25113. The T7 Expression System worked efficiently in this mutant strain named BW25113-T7. We demonstrated that this mutant strain could satisfactorily produce 5-Aminolevulinic Acid via C5 pathway. A final study was designed to enhance the controllability of T7 Expression System in this mutant strain by constructing a T7 Promoter Variants Library. These efforts advanced E. coli BW25113-T7 to be a practical host for future metabolic engineering efforts.
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Affiliation(s)
- Changchuan Ye
- State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, 100193, Beijing, China.,Beijing Key Laboratory of Bio-feed Additives, 100193, Beijing, China
| | - Xi Chen
- State Key Laboratory for Agro-Biotechnology, and Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant Pathology, China Agricultural University, 100193, Beijing, China
| | - Mengjie Yang
- National Feed Engineering Technology Research Centre, 100193, Beijing, China
| | - Xiangfang Zeng
- State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, 100193, Beijing, China.,Beijing Key Laboratory of Bio-feed Additives, 100193, Beijing, China
| | - Shiyan Qiao
- State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, 100193, Beijing, China. .,Beijing Key Laboratory of Bio-feed Additives, 100193, Beijing, China.
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102
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LuxAB-Based Microbial Cell Factories for the Sensing, Manufacturing and Transformation of Industrial Aldehydes. Catalysts 2021. [DOI: 10.3390/catal11080953] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The application of genetically encoded biosensors enables the detection of small molecules in living cells and has facilitated the characterization of enzymes, their directed evolution and the engineering of (natural) metabolic pathways. In this work, the LuxAB biosensor system from Photorhabdus luminescens was implemented in Escherichia coli to monitor the enzymatic production of aldehydes from primary alcohols and carboxylic acid substrates. A simple high-throughput assay utilized the bacterial luciferase—previously reported to only accept aliphatic long-chain aldehydes—to detect structurally diverse aldehydes, including aromatic and monoterpene aldehydes. LuxAB was used to screen the substrate scopes of three prokaryotic oxidoreductases: an alcohol dehydrogenase (Pseudomonas putida), a choline oxidase variant (Arthrobacter chlorophenolicus) and a carboxylic acid reductase (Mycobacterium marinum). Consequently, high-value aldehydes such as cinnamaldehyde, citral and citronellal could be produced in vivo in up to 80% yield. Furthermore, the dual role of LuxAB as sensor and monooxygenase, emitting bioluminescence through the oxidation of aldehydes to the corresponding carboxylates, promises implementation in artificial enzyme cascades for the synthesis of carboxylic acids. These findings advance the bio-based detection, preparation and transformation of industrially important aldehydes in living cells.
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103
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Luo ZW, Ahn JH, Chae TU, Choi SY, Park SY, Choi Y, Kim J, Prabowo CPS, Lee JA, Yang D, Han T, Xu H, Lee SY. Metabolic Engineering of
Escherichia
coli. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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104
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Towards robust Pseudomonas cell factories to harbour novel biosynthetic pathways. Essays Biochem 2021; 65:319-336. [PMID: 34223620 PMCID: PMC8314020 DOI: 10.1042/ebc20200173] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 05/01/2021] [Accepted: 05/24/2021] [Indexed: 02/07/2023]
Abstract
Biotechnological production in bacteria enables access to numerous valuable chemical compounds. Nowadays, advanced molecular genetic toolsets, enzyme engineering as well as the combinatorial use of biocatalysts, pathways, and circuits even bring new-to-nature compounds within reach. However, the associated substrates and biosynthetic products often cause severe chemical stress to the bacterial hosts. Species of the Pseudomonas clade thus represent especially valuable chassis as they are endowed with multiple stress response mechanisms, which allow them to cope with a variety of harmful chemicals. A built-in cell envelope stress response enables fast adaptations that sustain membrane integrity under adverse conditions. Further, effective export machineries can prevent intracellular accumulation of diverse harmful compounds. Finally, toxic chemicals such as reactive aldehydes can be eliminated by oxidation and stress-induced damage can be recovered. Exploiting and engineering these features will be essential to support an effective production of natural compounds and new chemicals. In this article, we therefore discuss major resistance strategies of Pseudomonads along with approaches pursued for their targeted exploitation and engineering in a biotechnological context. We further highlight strategies for the identification of yet unknown tolerance-associated genes and their utilisation for engineering next-generation chassis and finally discuss effective measures for pathway fine-tuning to establish stable cell factories for the effective production of natural compounds and novel biochemicals.
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105
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Yi D, Bayer T, Badenhorst CPS, Wu S, Doerr M, Höhne M, Bornscheuer UT. Recent trends in biocatalysis. Chem Soc Rev 2021; 50:8003-8049. [PMID: 34142684 PMCID: PMC8288269 DOI: 10.1039/d0cs01575j] [Citation(s) in RCA: 122] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Indexed: 12/13/2022]
Abstract
Biocatalysis has undergone revolutionary progress in the past century. Benefited by the integration of multidisciplinary technologies, natural enzymatic reactions are constantly being explored. Protein engineering gives birth to robust biocatalysts that are widely used in industrial production. These research achievements have gradually constructed a network containing natural enzymatic synthesis pathways and artificially designed enzymatic cascades. Nowadays, the development of artificial intelligence, automation, and ultra-high-throughput technology provides infinite possibilities for the discovery of novel enzymes, enzymatic mechanisms and enzymatic cascades, and gradually complements the lack of remaining key steps in the pathway design of enzymatic total synthesis. Therefore, the research of biocatalysis is gradually moving towards the era of novel technology integration, intelligent manufacturing and enzymatic total synthesis.
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Affiliation(s)
- Dong Yi
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Thomas Bayer
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Christoffel P. S. Badenhorst
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Shuke Wu
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Mark Doerr
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Matthias Höhne
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
| | - Uwe T. Bornscheuer
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University GreifswaldFelix-Hausdorff-Str. 4D-17487 GreifswaldGermany
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106
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The Role of Metabolic Engineering Technologies for the Production of Fatty Acids in Yeast. BIOLOGY 2021; 10:biology10070632. [PMID: 34356487 PMCID: PMC8301174 DOI: 10.3390/biology10070632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/22/2021] [Accepted: 06/30/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Metabolic engineering involves the sustainable production of high-value products. E. coli and yeast, in particular, are used for such processes. Using metabolic engineering, the biosynthetic pathways of these cells are altered to obtain a high production of desired products. Fatty acids (FAs) and their derivatives are products produced using metabolic engineering. However, classical methods used for engineering yeast metabolic pathways for the production of fatty acids and their derivatives face problems such as the low supply of key precursors and product tolerance. This review introduces the different ways FAs are being produced in E. coli and yeast and the genetic manipulations for enhanced production of FAs. The review also summarizes the latest techniques (i.e., CRISPR–Cas and synthetic biology) for developing FA-producing yeast cell factories. Abstract Metabolic engineering is a cutting-edge field that aims to produce simple, readily available, and inexpensive biomolecules by applying different genetic engineering and molecular biology techniques. Fatty acids (FAs) play an important role in determining the physicochemical properties of membrane lipids and are precursors of biofuels. Microbial production of FAs and FA-derived biofuels has several advantages in terms of sustainability and cost. Conventional yeast Saccharomyces cerevisiae is one of the models used for FA synthesis. Several genetic manipulations have been performed to enhance the citrate accumulation and its conversation into acetyl-CoA, a precursor for FA synthesis. Success has been achieved in producing different chemicals, including FAs and their derivatives, through metabolic engineering. However, several hurdles such as slow growth rate, low oleaginicity, and cytotoxicity are still need to be resolved. More robust research needs to be conducted on developing microbes capable of resisting diverse environments, chemicals, and cost-effective feed requirements. Redesigning microbes to produce FAs with cutting-edge synthetic biology and CRISPR techniques can solve these problems. Here, we reviewed the technological progression of metabolic engineering techniques and genetic studies conducted on S. cerevisiae, making it suitable as a model organism and a great candidate for the production of biomolecules, especially FAs.
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107
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108
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Jahnke K, Ritzmann N, Fichtler J, Nitschke A, Dreher Y, Abele T, Hofhaus G, Platzman I, Schröder RR, Müller DJ, Spatz JP, Göpfrich K. Proton gradients from light-harvesting E. coli control DNA assemblies for synthetic cells. Nat Commun 2021; 12:3967. [PMID: 34172734 PMCID: PMC8233306 DOI: 10.1038/s41467-021-24103-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/27/2021] [Indexed: 02/06/2023] Open
Abstract
Bottom-up and top-down approaches to synthetic biology each employ distinct methodologies with the common aim to harness living systems. Here, we realize a strategic merger of both approaches to convert light into proton gradients for the actuation of synthetic cellular systems. We genetically engineer E. coli to overexpress the light-driven inward-directed proton pump xenorhodopsin and encapsulate them in artificial cell-sized compartments. Exposing the compartments to light-dark cycles, we reversibly switch the pH by almost one pH unit and employ these pH gradients to trigger the attachment of DNA structures to the compartment periphery. For this purpose, a DNA triplex motif serves as a nanomechanical switch responding to the pH-trigger of the E. coli. When DNA origami plates are modified with the pH-sensitive triplex motif, the proton-pumping E. coli can trigger their attachment to giant unilamellar lipid vesicles (GUVs) upon illumination. A DNA cortex is formed upon DNA origami polymerization, which sculpts and deforms the GUVs. We foresee that the combination of bottom-up and top down approaches is an efficient way to engineer synthetic cells.
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Affiliation(s)
- Kevin Jahnke
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Noah Ritzmann
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland
| | - Julius Fichtler
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Anna Nitschke
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Yannik Dreher
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Tobias Abele
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Götz Hofhaus
- Centre for Advanced Materials, Heidelberg, Germany
| | - Ilia Platzman
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Heidelberg, Germany
- Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Heidelberg, Germany
| | | | - Daniel J Müller
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland
| | - Joachim P Spatz
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Heidelberg, Germany
- Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Heidelberg, Germany
- Max Planck School Matter to Life, Heidelberg, Germany
| | - Kerstin Göpfrich
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany.
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.
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109
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Soma Y, Takahashi M, Fujiwara Y, Shinohara T, Izumi Y, Hanai T, Bamba T. Design of Synthetic Quorum Sensing Achieving Induction Timing-Independent Signal Stabilization for Dynamic Metabolic Engineering of E. coli. ACS Synth Biol 2021; 10:1384-1393. [PMID: 34106678 DOI: 10.1021/acssynbio.1c00008] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Dynamic metabolic engineering that harnesses synthetic biological tools is a next-generation strategy for microbial chemical and fuel production. We previously reported a synthetic quorum sensing system combined with a metabolic toggle switch (QS-MTS) in E. coli. It autonomously redirected endogenous metabolic flux toward the synthetic metabolic pathway and improved biofuel production. However, its functions and effects on host metabolism were attenuated by induction timing delay. Here, we redesigned the QS-MTS to stabilize QS signaling efficiency and metabolic regulation. We performed a metabolome analysis to clarify the effects of QS-MTS redesign on host metabolism. We compared the contributions of conventional and redesigned QS-MTS to fed-batch fermentation. The redesigned QS-MTS was more conducive than the conventional QS-MTS to long-term processes such as fed-batch fermentation. Here, we present a circuit redesign for metabolic flux control based on dynamic characteristic evaluation and metabolome analysis.
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Affiliation(s)
- Yuki Soma
- Division of Metabolomics, Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masatomo Takahashi
- Division of Metabolomics, Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yuri Fujiwara
- Division of Metabolomics, Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tamaki Shinohara
- Division of Metabolomics, Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yoshihiro Izumi
- Division of Metabolomics, Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Taizo Hanai
- Laboratory for Bioinformatics, Graduate School of Systems Lifesciences, Kyushu University, W5-729, 744, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Takeshi Bamba
- Division of Metabolomics, Research Center for Transomics Medicine, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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110
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Guo L, Lu J, Gao C, Zhang L, Liu L, Chen X. Dynamic control of the distribution of carbon flux between cell growth and butyrate biosynthesis in Escherichia coli. Appl Microbiol Biotechnol 2021; 105:5173-5187. [PMID: 34115183 DOI: 10.1007/s00253-021-11385-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 05/05/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022]
Abstract
Microbial cell factories offer an economic and environmentally friendly method for the biosynthesis of acetyl-CoA-derived chemicals. However, the static control of carbon flux can cause direct and indirect competition for acetyl-CoA between cell growth and chemical biosynthesis, limiting the efficiency of microbial cell factories. Herein, recombinase-based genetic circuits were developed to achieve the optimal distribution of acetyl-CoA between cell growth and butyrate biosynthesis. First, three dynamic devices-a turn-on switch, a turn-off switch, and a recombinase-based inverter (RBI)-were constructed based on Bxb1 recombinase. Then, the turn-on switch was used to dynamically control the butyrate biosynthetic pathway, which directly improved the consumption of acetyl-CoA. Next, the turn-off switch was applied to dynamically control cell growth, which indirectly enhanced the supply of acetyl-CoA. Finally, an RBI was adopted for the dynamic dual control of the distribution of acetyl-CoA between cell growth and butyrate biosynthesis. The final butyrate production rate was increased to 34 g/L, with a productivity of 0.405 g/L/h. The strategy described herein will pave the way for the development of high-performance microbial cell factories for the production of other desirable chemicals. KEY POINTS: • Competition for acetyl-CoA between cell growth and synthesis limits productivity. • Recombinase-based genetic circuits were developed to dynamic control of acetyl-CoA. • Optimal distribution of acetyl-CoA between cell growth and synthesis was achieved.
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Affiliation(s)
- Liang Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Jiaxin Lu
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Linpei Zhang
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China.
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China.
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111
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Wu J, Li W, Zhao SG, Qian SH, Wang Z, Zhou MJ, Hu WS, Wang J, Hu LX, Liu Y, Xue ZL. Site-directed mutagenesis of the quorum-sensing transcriptional regulator SinR affects the biosynthesis of menaquinone in Bacillus subtilis. Microb Cell Fact 2021; 20:113. [PMID: 34098969 PMCID: PMC8183045 DOI: 10.1186/s12934-021-01603-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/31/2021] [Indexed: 01/02/2023] Open
Abstract
Background Menaquinone (MK-7) is a highly valuable vitamin K2 produced by Bacillus subtilis. Common static metabolic engineering approaches for promoting the production of MK-7 have been studied previously. However, these approaches caused an accumulation of toxic substances and reduced product yield. Hence, dynamic regulation by the quorum sensing (QS) system is a promising method for achieving a balance between product synthesis and cell growth. Results In this study, the QS transcriptional regulator SinR, which plays a significant role in biofilm formation and MK production simultaneously, was selected, and its site-directed mutants were constructed. Among these mutants, sinR knock out strain (KO-SinR) increased the biofilm biomass by 2.8-fold compared to the wild-type. SinRquad maximized the yield of MK-7 (102.56 ± 2.84 mg/L). To decipher the mechanism of how this mutant regulates MK-7 synthesis and to find additional potential regulators that enhance MK-7 synthesis, RNA-seq was used to analyze expression changes in the QS system, biofilm formation, and MK-7 synthesis pathway. The results showed that the expressions of tapA, tasA and epsE were up-regulated 9.79-, 0.95-, and 4.42-fold, respectively. Therefore, SinRquad formed more wrinkly and smoother biofilms than BS168. The upregulated expressions of glpF, glpk, and glpD in this biofilm morphology facilitated the flow of glycerol through the biofilm. In addition, NADH dehydrogenases especially sdhA, sdhB, sdhC and glpD, increased 1.01-, 3.93-, 1.87-, and 1.11-fold, respectively. The increased expression levels of NADH dehydrogenases indicated that more electrons were produced for the electron transport system. Electrical hyperpolarization stimulated the synthesis of the electron transport chain components, such as cytochrome c and MK, to ensure the efficiency of electron transfer. Wrinkly and smooth biofilms formed a network of interconnected channels with a low resistance to liquid flow, which was beneficial for the uptake of glycerol, and facilitated the metabolic flux of four modules of the MK-7 synthesis pathway. Conclusions In this study, we report for the first time that SinRquad has significant effects on MK-7 synthesis by forming wrinkly and smooth biofilms, upregulating the expression level of most NADH dehydrogenases, and providing higher membrane potential to stimulate the accumulation of the components in the electron transport system. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01603-5.
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Affiliation(s)
- Jing Wu
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China
| | - Wei Li
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China
| | - Shi-Guang Zhao
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu, 241000, China
| | - Sen-He Qian
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu, 241000, China
| | - Zhou Wang
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu, 241000, China
| | - Meng-Jie Zhou
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China
| | - Wen-Song Hu
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China
| | - Jian Wang
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China
| | - Liu-Xiu Hu
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China.,Wuhu Zhanghengchun Medicine CO., LTD, Wuhu, 241000, China
| | - Yan Liu
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China. .,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu, 241000, China.
| | - Zheng-Lian Xue
- College of Biology and Food Engineering, Anhui Polytechnic University, Wuhu, 241000, China. .,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu, 241000, China.
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112
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Abstract
Metabolic engineering reprograms cells to synthesize value-added products. In doing so, endogenous genes are altered and heterologous genes can be introduced to achieve the necessary enzymatic reactions. Dynamic regulation of metabolic flux is a powerful control scheme to alleviate and overcome the competing cellular objectives that arise from the introduction of these production pathways. This review explores dynamic regulation strategies that have demonstrated significant production benefits by targeting the metabolic node corresponding to a specific challenge. We summarize the stimulus-responsive control circuits employed in these strategies that determine the criterion for actuating a dynamic response and then examine the points of control that couple the stimulus-responsive circuit to a shift in metabolic flux.
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Affiliation(s)
- Cynthia Ni
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
| | - Christina V Dinh
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
| | - Kristala L J Prather
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
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113
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Ni C, Fox KJ, Prather KLJ. Substrate-activated expression of a biosynthetic pathway in Escherichia coli. Biotechnol J 2021; 17:e2000433. [PMID: 34050620 DOI: 10.1002/biot.202000433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 11/12/2022]
Abstract
Microbes can facilitate production of valuable chemicals more sustainably than traditional chemical processes in many cases: they utilize renewable feedstocks, require less energy intensive process conditions, and perform a variety of chemical reactions using endogenous or heterologous enzymes. In response to the metabolic burden imposed by production pathways, chemical inducers are frequently used to initiate gene expression after the cells have reached sufficient density. While chemically inducible promoters are a common research tool used for pathway expression, they introduce a compound extrinsic to the process along with the associated costs. We developed an expression control system for a biosynthetic pathway for the production of d-glyceric acid that utilizes galacturonate as both the inducer and the substrate, thereby eliminating the need for an extrinsic chemical inducer. Activation of expression in response to the feed is actuated by a galacturonate-responsive transcription factor biosensor. We constructed variants of the galacturonate biosensor with a heterologous transcription factor and cognate hybrid promoter, and selected for the best performer through fluorescence characterization. We showed that native E. coli regulatory systems do not interact with our biosensor and favorable biosensor response exists in the presence and absence of galacturonate consumption. We then employed the control circuit to regulate the expression of the heterologous genes of a biosynthetic pathway for the production d-glyceric acid that was previously developed in our lab. Productivity via substrate-induction with our control circuit was comparable to IPTG-controlled induction and significantly outperformed a constitutive expression control, producing 2.13 ± 0.03 g L-1 d-glyceric acid within 6 h of galacturonate substrate addition. This work demonstrated feed-activated pathway expression to be an attractive control strategy for more readily scalable microbial biosynthesis.
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Affiliation(s)
- Cynthia Ni
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kevin J Fox
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kristala L J Prather
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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114
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Glasscock CJ, Biggs BW, Lazar JT, Arnold JH, Burdette LA, Valdes A, Kang MK, Tullman-Ercek D, Tyo KEJ, Lucks JB. Dynamic Control of Gene Expression with Riboregulated Switchable Feedback Promoters. ACS Synth Biol 2021; 10:1199-1213. [PMID: 33834762 DOI: 10.1021/acssynbio.1c00015] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One major challenge in synthetic biology is the deleterious impacts of cellular stress caused by expression of heterologous pathways, sensors, and circuits. Feedback control and dynamic regulation are broadly proposed strategies to mitigate this cellular stress by optimizing gene expression levels temporally and in response to biological cues. While a variety of approaches for feedback implementation exist, they are often complex and cannot be easily manipulated. Here, we report a strategy that uses RNA transcriptional regulators to integrate additional layers of control over the output of natural and engineered feedback responsive circuits. Called riboregulated switchable feedback promoters (rSFPs), these gene expression cassettes can be modularly activated using multiple mechanisms, from manual induction to autonomous quorum sensing, allowing control over the timing, magnitude, and autonomy of expression. We develop rSFPs in Escherichia coli to regulate multiple feedback networks and apply them to control the output of two metabolic pathways. We envision that rSFPs will become a valuable tool for flexible and dynamic control of gene expression in metabolic engineering, biological therapeutic production, and many other applications.
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Affiliation(s)
- Cameron J. Glasscock
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Bradley W. Biggs
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - John T. Lazar
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Jack H. Arnold
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Lisa A. Burdette
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Aliki Valdes
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Min-Kyoung Kang
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Danielle Tullman-Ercek
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Keith E. J. Tyo
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Julius B. Lucks
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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115
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Ding N, Zhou S, Deng Y. Transcription-Factor-based Biosensor Engineering for Applications in Synthetic Biology. ACS Synth Biol 2021; 10:911-922. [PMID: 33899477 DOI: 10.1021/acssynbio.0c00252] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Transcription-factor-based biosensors (TFBs) are often used for metabolite detection, adaptive evolution, and metabolic flux control. However, designing TFBs with superior performance for applications in synthetic biology remains challenging. Specifically, natural TFBs often do not meet real-time detection requirements owing to their slow response times and inappropriate dynamic ranges, detection ranges, sensitivity, and selectivity. Furthermore, designing and optimizing complex dynamic regulation networks is time-consuming and labor-intensive. This Review highlights TFB-based applications and recent engineering strategies ranging from traditional trial-and-error approaches to novel computer-model-based rational design approaches. The limitations of the applications and these engineering strategies are additionally reviewed.
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Affiliation(s)
- Nana Ding
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Shenghu Zhou
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Yu Deng
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
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116
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Almeida BC, Kaczmarek JA, Figueiredo PR, Prather KLJ, Carvalho ATP. Transcription factor allosteric regulation through substrate coordination to zinc. NAR Genom Bioinform 2021; 3:lqab033. [PMID: 33987533 PMCID: PMC8092373 DOI: 10.1093/nargab/lqab033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/30/2021] [Accepted: 04/08/2021] [Indexed: 11/14/2022] Open
Abstract
The development of new synthetic biology circuits for biotechnology and medicine requires deeper mechanistic insight into allosteric transcription factors (aTFs). Here we studied the aTF UxuR, a homodimer of two domains connected by a highly flexible linker region. To explore how ligand binding to UxuR affects protein dynamics we performed molecular dynamics simulations in the free protein, the aTF bound to the inducer D-fructuronate or the structural isomer D-glucuronate. We then validated our results by constructing a sensor plasmid for D-fructuronate in Escherichia coli and performed site-directed mutagenesis. Our results show that zinc coordination is necessary for UxuR function since mutation to alanines prevents expression de-repression by D-fructuronate. Analyzing the different complexes, we found that the disordered linker regions allow the N-terminal domains to display fast and large movements. When the inducer is bound, UxuR can sample an open conformation with a more pronounced negative charge at the surface of the N-terminal DNA binding domains. In opposition, in the free and D-glucuronate bond forms the protein samples closed conformations, with a more positive character at the surface of the DNA binding regions. These molecular insights provide a new basis to harness these systems for biological systems engineering.
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Affiliation(s)
- Beatriz C Almeida
- CNC-Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
| | - Jennifer A Kaczmarek
- MIT-Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Pedro R Figueiredo
- CNC-Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
| | - Kristala L J Prather
- MIT-Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alexandra T P Carvalho
- CNC-Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
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117
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Sharma A, Yazdani SS. Microbial engineering to produce fatty alcohols and alkanes. J Ind Microbiol Biotechnol 2021; 48:6169711. [PMID: 33713132 DOI: 10.1093/jimb/kuab011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/18/2020] [Indexed: 11/14/2022]
Abstract
Owing to their high energy density and composition, fatty acid-derived chemicals possess a wide range of applications such as biofuels, biomaterials, and other biochemical, and as a consequence, the global annual demand for products has surpassed 2 million tons. With the exhausting petroleum reservoirs and emerging environmental concerns on using petroleum feedstock, it has become indispensable to shift to a renewable-based industry. With the advancement in the field of synthetic biology and metabolic engineering, the use of microbes as factories for the production of fatty acid-derived chemicals is becoming a promising alternative approach for the production of these derivatives. Numerous metabolic approaches have been developed for conditioning the microbes to improve existing or develop new methodologies capable of efficient oleochemical production. However, there still exist several limitations that need to be addressed for the commercial viability of the microbial cell factory production. Though substantial advancement has been made toward successfully producing these fatty acids derived chemicals, a considerable amount of work needs to be done for improving the titers. In the present review, we aim to address the roadblocks impeding the heterologous production, the engineering pathway strategies implemented across the range of microbes in a detailed manner, and the commercial readiness of these molecules of immense application.
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Affiliation(s)
- Ashima Sharma
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.,DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India.,DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
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118
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Dacquay LC, McMillen DR. Improving the design of an oxidative stress sensing biosensor in yeast. FEMS Yeast Res 2021; 21:6232160. [PMID: 33864457 PMCID: PMC8088429 DOI: 10.1093/femsyr/foab025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/15/2021] [Indexed: 12/23/2022] Open
Abstract
Transcription factor (TF)-based biosensors have proven useful for increasing biomanufacturing yields, large-scale functional screening, and in environmental monitoring. Most yeast TF-based biosensors are built from natural promoters, resulting in large DNA parts retaining considerable homology to the host genome, which can complicate biological engineering efforts. There is a need to explore smaller, synthetic biosensors to expand the options for regulating gene expression in yeast. Here, we present a systematic approach to improving the design of an existing oxidative stress sensing biosensor in Saccharomyces cerevisiae based on the Yap1 transcription factor. Starting from a synthetic core promoter, we optimized the activity of a Yap1-dependent promoter through rational modification of a minimalist Yap1 upstream activating sequence. Our novel promoter achieves dynamic ranges of activation surpassing those of the previously engineered Yap1-dependent promoter, while reducing it to only 171 base pairs. We demonstrate that coupling the promoter to a positive-feedback-regulated TF further improves the biosensor by increasing its dynamic range of activation and reducing its limit of detection. We have illustrated the robustness and transferability of the biosensor by reproducing its activity in an unconventional probiotic yeast strain, Saccharomyces boulardii. Our findings can provide guidance in the general process of TF-based biosensor design.
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Affiliation(s)
- Louis C Dacquay
- Dept of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, ON M5S 3G5, Canada.,Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga ON L5L 1C6, Canada
| | - David R McMillen
- Dept of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, ON M5S 3G5, Canada.,Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga ON L5L 1C6, Canada.,Departments of Chemistry and Physics, University of Toronto, 80 St. George St., Toronto ON M5S 3H6, Canada
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119
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Genetic circuits combined with machine learning provides fast responding living sensors. Biosens Bioelectron 2021; 178:113028. [DOI: 10.1016/j.bios.2021.113028] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/05/2021] [Accepted: 01/19/2021] [Indexed: 12/24/2022]
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120
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Rondon R, Wilson CJ. Engineering Alternate Ligand Recognition in the PurR Topology: A System of Novel Caffeine Biosensing Transcriptional Antirepressors. ACS Synth Biol 2021; 10:552-565. [PMID: 33689294 DOI: 10.1021/acssynbio.0c00582] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recent advances in synthetic biology and protein engineering have increased the number of allosteric transcription factors used to regulate independent promoters. These developments represent an important increase in our biological computing capacity, which will enable us to construct more sophisticated genetic programs for a broad range of biological technologies. However, the majority of these transcription factors are represented by the repressor phenotype (BUFFER), and require layered inversion to confer the antithetical logical function (NOT), requiring additional biological resources. Moreover, these engineered transcription factors typically utilize native ligand binding functions paired with alternate DNA binding functions. In this study, we have advanced the state-of-the-art by engineering and redesigning the PurR topology (a native antirepressor) to be responsive to caffeine, while mitigating responsiveness to the native ligand hypoxanthine-i.e., a deamination product of the input molecule adenine. Importantly, the resulting caffeine responsive transcription factors are not antagonized by the native ligand hypoxanthine. In addition, we conferred alternate DNA binding to the caffeine antirepressors, and to the PurR scaffold, creating 38 new transcription factors that are congruent with our current transcriptional programming structure. Finally, we leveraged this system of transcription factors to create integrated NOR logic and related feedback operations. This study represents the first example of a system of transcription factors (antirepressors) in which both the ligand binding site and the DNA binding functions were successfully engineered in tandem.
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Affiliation(s)
- Ronald Rondon
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, 311 Ferst Drive, Atlanta, Georgia 30332-0100, United States
| | - Corey J. Wilson
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, 311 Ferst Drive, Atlanta, Georgia 30332-0100, United States
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121
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Yuan P, Sun G, Cui S, Wu Y, Lv X, Liu Y, Li J, Du G, Liu L. Engineering a ComA Quorum-Sensing circuit to dynamically control the production of Menaquinone-4 in Bacillus subtilis. Enzyme Microb Technol 2021; 147:109782. [PMID: 33992404 DOI: 10.1016/j.enzmictec.2021.109782] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 12/29/2022]
Abstract
Menaquinone-4 (MK-4) plays a significant role in bone health and cardiovascular therapy. Although many strategies have been adopted to increase the yield of MK-4 in Bacillus subtilis 168, the effectiveness of MK-4 is still low due to the inherent limitations of metabolic pathways. However, dynamic regulation based on quorum sensing (QS) has been extensively applied as a fundamental tool for fine-tuning gene expression in reaction to changes in cell density without adding expensive inducers. Nevertheless, in most reports, QS systems depend on down-regulated expression rather than up-regulated expression, which greatly limit their potential as molecular switches to control metabolic flux. To address this challenge, a modular PhrQ-RapQ-ComA QS system is developed based on promoter PA11, which is up-regulated by phosphorylated ComA (ComA-P). In this paper, firstly we analyzed the ComA-based gene expression regulation system in Bacillus subtilis 168. We constructed a promoter library of diff ;erent abilities, selected best promoters from a library, and performed mutation screening on the selected promoters. Furthermore, we constructed a PhrQ-RapQ-ComA QS system to dynamically control the synthesis of MK-4 in B. subtilis 168. Cell growth and efficient synthesis of the target product can be dynamically balanced by the QS system. Our dynamic adjustment approach increased the yield of MK-4 in shake flask from 120.1 ± 0.6 to 178.9 ± 2.8 mg/L, and reached 217 ± 4.1 mg/L in a 3-L bioreactor, which verified the effectiveness of this strategy. In summary, PhrQ-RapQ-ComA QS system can realize dynamic pathway regulation in B. subtilis 168, which can be stretched to a great deal of microorganisms to fine-tune gene expression and enhance the production of metabolites.
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Affiliation(s)
- Panhong Yuan
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Guoyun Sun
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Shixiu Cui
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Yaokang Wu
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xueqin Lv
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Yanfeng Liu
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Jianghua Li
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Guocheng Du
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Long Liu
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
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122
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Switching metabolic flux by engineering tryptophan operon-assisted CRISPR interference system in Klebsiella pneumoniae. Metab Eng 2021; 65:30-41. [PMID: 33684594 DOI: 10.1016/j.ymben.2021.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/22/2020] [Accepted: 03/01/2021] [Indexed: 01/17/2023]
Abstract
One grand challenge for bioproduction of desired metabolites is how to coordinate cell growth and product synthesis. Here we report that a tryptophan operon-assisted CRISPR interference (CRISPRi) system can switch glycerol oxidation and reduction pathways in Klebsiella pneumoniae, whereby the oxidation pathway provides energy to sustain growth, and the reduction pathway generates 1,3-propanediol and 3-hydroxypropionic acid (3-HP), two economically important chemicals. Reverse transcription and quantitative PCR (RT-qPCR) showed that this CRISPRi-dependent switch affected the expression of glycerol metabolism-related genes and in turn improved 3-HP production. In shake-flask cultivation, the strain coexpressing dCas9-sgRNA and PuuC (an aldehyde dehydrogenase native to K. pneumoniae for 3-HP biosynthesis) produced 3.6 g/L 3-HP, which was 1.62 times that of the strain only overexpressing PuuC. In a 5 L bioreactor, this CRISPRi strain produced 58.9 g/L 3-HP. When circulation feeding was implemented to alleviate metabolic stress, biomass was substantially improved and 88.8 g/L 3-HP was produced. These results indicated that this CRISPRi-dependent switch can efficiently reconcile biomass formation and 3-HP biosynthesis. Furthermore, this is the first report of coupling CRISPRi system with trp operon, and this architecture holds huge potential in regulating gene expression and allocating metabolic flux.
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123
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Aduhene AG, Cui H, Yang H, Liu C, Sui G, Liu C. Poly(3-hydroxypropionate): Biosynthesis Pathways and Malonyl-CoA Biosensor Material Properties. Front Bioeng Biotechnol 2021; 9:646995. [PMID: 33748091 PMCID: PMC7978226 DOI: 10.3389/fbioe.2021.646995] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/09/2021] [Indexed: 01/25/2023] Open
Abstract
Many single-use non-degradable plastics are a threat to life today, and several polyhydroxyalkanoates (PHAs) biopolymers have been developed in the bioplastic industry to place petrochemical-based plastics. One of such is the novel biomaterial poly(3-hydroxypropionate) [poly(3HP)] because of its biocompatibility, biodegradability, and high yield synthesis using engineered strains. To date, many bio-polymer-based functional composites have been developed to increase the value of raw microbial-biopolymers obtained from cheap sources. This review article broadly covers poly(3HP), a comprehensive summary of critical biosynthetic production pathways comparing the yields and titers achieved in different Microbial cell Factories. This article also provides extensive knowledge and highlights recent progress on biosensors' use to optimize poly(3HP) production, some bacteria host adopted for production, chemical and physical properties, life cycle assessment for poly(3HP) production using corn oil as carbon source, and some essential medical applications of poly(3HP).
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Affiliation(s)
- Albert Gyapong Aduhene
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin, China.,College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Hongliang Cui
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin, China.,College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Hongyi Yang
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Chengwei Liu
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Guangchao Sui
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Changli Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin, China.,College of Life Sciences, Northeast Forestry University, Harbin, China
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124
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Awad G, Garnier A. Maximization of saturated fatty acids through the production of P450BM3 monooxygenase in the engineered Escherichia coli. FOOD AND BIOPRODUCTS PROCESSING 2021. [DOI: 10.1016/j.fbp.2021.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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125
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Fine tuning the glycolytic flux ratio of EP-bifido pathway for mevalonate production by enhancing glucose-6-phosphate dehydrogenase (Zwf) and CRISPRi suppressing 6-phosphofructose kinase (PfkA) in Escherichia coli. Microb Cell Fact 2021; 20:32. [PMID: 33531004 PMCID: PMC7852082 DOI: 10.1186/s12934-021-01526-1] [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: 07/25/2020] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Natural glycolysis encounters the decarboxylation of glucose partial oxidation product pyruvate into acetyl-CoA, where one-third of the carbon is lost at CO2. We previously constructed a carbon saving pathway, EP-bifido pathway by combining Embden-Meyerhof-Parnas Pathway, Pentose Phosphate Pathway and "bifid shunt", to generate high yield acetyl-CoA from glucose. However, the carbon conversion rate and reducing power of this pathway was not optimal, the flux ratio of EMP pathway and pentose phosphate pathway (PPP) needs to be precisely and dynamically adjusted to improve the production of mevalonate (MVA). RESULT Here, we finely tuned the glycolytic flux ratio in two ways. First, we enhanced PPP flux for NADPH supply by replacing the promoter of zwf on the genome with a set of different strength promoters. Compared with the previous EP-bifido strains, the zwf-modified strains showed obvious differences in NADPH, NADH, and ATP synthesis levels. Among them, strain BP10BF accumulated 11.2 g/L of MVA after 72 h of fermentation and the molar conversion rate from glucose reached 62.2%. Second, pfkA was finely down-regulated by the clustered regularly interspaced short palindromic repeats interference (CRISPRi) system. The MVA yield of the regulated strain BiB1F was 8.53 g/L, and the conversion rate from glucose reached 68.7%. CONCLUSION This is the highest MVA conversion rate reported in shaken flask fermentation. The CRISPRi and promoter fine-tuning provided an effective strategy for metabolic flux redistribution in many metabolic pathways and promotes the chemicals production.
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126
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Liu Y, Benitez MG, Chen J, Harrison E, Khusnutdinova AN, Mahadevan R. Opportunities and Challenges for Microbial Synthesis of Fatty Acid-Derived Chemicals (FACs). Front Bioeng Biotechnol 2021; 9:613322. [PMID: 33575251 PMCID: PMC7870715 DOI: 10.3389/fbioe.2021.613322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 01/04/2021] [Indexed: 11/13/2022] Open
Abstract
Global warming and uneven distribution of fossil fuels worldwide concerns have spurred the development of alternative, renewable, sustainable, and environmentally friendly resources. From an engineering perspective, biosynthesis of fatty acid-derived chemicals (FACs) is an attractive and promising solution to produce chemicals from abundant renewable feedstocks and carbon dioxide in microbial chassis. However, several factors limit the viability of this process. This review first summarizes the types of FACs and their widely applications. Next, we take a deep look into the microbial platform to produce FACs, give an outlook for the platform development. Then we discuss the bottlenecks in metabolic pathways and supply possible solutions correspondingly. Finally, we highlight the most recent advances in the fast-growing model-based strain design for FACs biosynthesis.
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Affiliation(s)
- Yilan Liu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Mauricio Garcia Benitez
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Jinjin Chen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Emma Harrison
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Anna N. Khusnutdinova
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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127
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Jiang T, Li C, Yan Y. Optimization of a p-Coumaric Acid Biosensor System for Versatile Dynamic Performance. ACS Synth Biol 2021; 10:132-144. [PMID: 33378169 DOI: 10.1021/acssynbio.0c00500] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Metabolic engineering is a promising approach for the synthesis of valuable compounds. Transcriptional factor-based biosensors are efficient tools to regulate the metabolic pathway dynamically. Here, we engineered the p-coumaric acid responsive regulator PadR from Bacillus subtilis. We found that yveF and yveG, two previously uncharacterized components in the sensor system, showed positive impacts on the regulation of PadR-PpadC sensor system, mostly on assisting the release of the repression by PadR. By site directed PadR engineering, we obtained two mutants, K64A and H38A, which exhibited increased dynamic range and superior sensitivity. To increase the promoter strength of the sensor system and investigate whether the PadR binding boxes can function in a "plug-and-play" manner, a series of hybrid promoters were constructed. Four of them, P1, P2, P7, and P9, showed increased strength compared to PpadC and can be regulated by PadR and p-coumaric acid. The PadR variants and hybrid promoters obtained in this paper would expand the applicability of this sensor system in future metabolic engineering research.
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Affiliation(s)
- Tian Jiang
- School of Chemical, Materials, and Biomedical Engineering, College of Engineering, The University of Georgia, Athens, Georgia 30602, United States
| | - Chenyi Li
- School of Chemical, Materials, and Biomedical Engineering, College of Engineering, The University of Georgia, Athens, Georgia 30602, United States
| | - Yajun Yan
- School of Chemical, Materials, and Biomedical Engineering, College of Engineering, The University of Georgia, Athens, Georgia 30602, United States
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128
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Hartline CJ, Schmitz AC, Han Y, Zhang F. Dynamic control in metabolic engineering: Theories, tools, and applications. Metab Eng 2021; 63:126-140. [PMID: 32927059 PMCID: PMC8015268 DOI: 10.1016/j.ymben.2020.08.015] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/15/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022]
Abstract
Metabolic engineering has allowed the production of a diverse number of valuable chemicals using microbial organisms. Many biological challenges for improving bio-production exist which limit performance and slow the commercialization of metabolically engineered systems. Dynamic metabolic engineering is a rapidly developing field that seeks to address these challenges through the design of genetically encoded metabolic control systems which allow cells to autonomously adjust their flux in response to their external and internal metabolic state. This review first discusses theoretical works which provide mechanistic insights and design choices for dynamic control systems including two-stage, continuous, and population behavior control strategies. Next, we summarize molecular mechanisms for various sensors and actuators which enable dynamic metabolic control in microbial systems. Finally, important applications of dynamic control to the production of several metabolite products are highlighted, including fatty acids, aromatics, and terpene compounds. Altogether, this review provides a comprehensive overview of the progress, advances, and prospects in the design of dynamic control systems for improved titer, rate, and yield metrics in metabolic engineering.
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Affiliation(s)
- Christopher J Hartline
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA
| | - Alexander C Schmitz
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA
| | - Yichao Han
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA; Division of Biological & Biomedical Sciences, Washington University in St. Louis, Saint Louis, MO, 63130, USA; Institute of Materials Science & Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA.
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129
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Otero-Muras I, Carbonell P. Automated engineering of synthetic metabolic pathways for efficient biomanufacturing. Metab Eng 2020; 63:61-80. [PMID: 33316374 DOI: 10.1016/j.ymben.2020.11.012] [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] [Received: 08/22/2020] [Revised: 11/15/2020] [Accepted: 11/20/2020] [Indexed: 12/19/2022]
Abstract
Metabolic engineering involves the engineering and optimization of processes from single-cell to fermentation in order to increase production of valuable chemicals for health, food, energy, materials and others. A systems approach to metabolic engineering has gained traction in recent years thanks to advances in strain engineering, leading to an accelerated scaling from rapid prototyping to industrial production. Metabolic engineering is nowadays on track towards a truly manufacturing technology, with reduced times from conception to production enabled by automated protocols for DNA assembly of metabolic pathways in engineered producer strains. In this review, we discuss how the success of the metabolic engineering pipeline often relies on retrobiosynthetic protocols able to identify promising production routes and dynamic regulation strategies through automated biodesign algorithms, which are subsequently assembled as embedded integrated genetic circuits in the host strain. Those approaches are orchestrated by an experimental design strategy that provides optimal scheduling planning of the DNA assembly, rapid prototyping and, ultimately, brings forward an accelerated Design-Build-Test-Learn cycle and the overall optimization of the biomanufacturing process. Achieving such a vision will address the increasingly compelling demand in our society for delivering valuable biomolecules in an affordable, inclusive and sustainable bioeconomy.
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Affiliation(s)
- Irene Otero-Muras
- BioProcess Engineering Group, IIM-CSIC, Spanish National Research Council, Vigo, 36208, Spain.
| | - Pablo Carbonell
- Institute of Industrial Control Systems and Computing (ai2), Universitat Politècnica de València, 46022, Spain.
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130
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Wan X, Pinto F, Yu L, Wang B. Synthetic protein-binding DNA sponge as a tool to tune gene expression and mitigate protein toxicity. Nat Commun 2020; 11:5961. [PMID: 33235249 PMCID: PMC7686491 DOI: 10.1038/s41467-020-19552-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/20/2020] [Indexed: 12/17/2022] Open
Abstract
Versatile tools for gene expression regulation are vital for engineering gene networks of increasing scales and complexity with bespoke responses. Here, we investigate and repurpose a ubiquitous, indirect gene regulation mechanism from nature, which uses decoy protein-binding DNA sites, named DNA sponge, to modulate target gene expression in Escherichia coli. We show that synthetic DNA sponges can be designed to reshape the response profiles of gene circuits, lending multifaceted tuning capacities including reducing basal leakage by >20-fold, increasing system output amplitude by >130-fold and dynamic range by >70-fold, and mitigating host growth inhibition by >20%. Further, multi-layer DNA sponges for decoying multiple regulatory proteins provide an additive tuning effect on the responses of layered circuits compared to single-layer sponges. Our work shows synthetic DNA sponges offer a simple yet generalizable route to systematically engineer the performance of synthetic gene circuits, expanding the current toolkit for gene regulation with broad potential applications. Decoy binding sites are natural regulators of gene expression. Here the authors design synthetic DNA sponges that fine tune the performance of synthetic gene circuits in a simple yet systematic manner, expanding the synthetic biology toolkit for gene regulation.
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Affiliation(s)
- Xinyi Wan
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK.,Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Filipe Pinto
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK.,Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Luyang Yu
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.,Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, 314400, China
| | - Baojun Wang
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK. .,Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK. .,College of Life Sciences, Zhejiang University, Hangzhou, 310058, China. .,Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, 314400, China.
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131
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Amer M, Toogood H, Scrutton NS. Engineering nature for gaseous hydrocarbon production. Microb Cell Fact 2020; 19:209. [PMID: 33187524 PMCID: PMC7661322 DOI: 10.1186/s12934-020-01470-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 11/04/2020] [Indexed: 11/10/2022] Open
Abstract
The development of sustainable routes to the bio-manufacture of gaseous hydrocarbons will contribute widely to future energy needs. Their realisation would contribute towards minimising over-reliance on fossil fuels, improving air quality, reducing carbon footprints and enhancing overall energy security. Alkane gases (propane, butane and isobutane) are efficient and clean-burning fuels. They are established globally within the transportation industry and are used for domestic heating and cooking, non-greenhouse gas refrigerants and as aerosol propellants. As no natural biosynthetic routes to short chain alkanes have been discovered, de novo pathways have been engineered. These pathways incorporate one of two enzymes, either aldehyde deformylating oxygenase or fatty acid photodecarboxylase, to catalyse the final step that leads to gas formation. These new pathways are derived from established routes of fatty acid biosynthesis, reverse β-oxidation for butanol production, valine biosynthesis and amino acid degradation. Single-step production of alkane gases in vivo is also possible, where one recombinant biocatalyst can catalyse gas formation from exogenously supplied short-chain fatty acid precursors. This review explores current progress in bio-alkane gas production, and highlights the potential for implementation of scalable and sustainable commercial bioproduction hubs.
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Affiliation(s)
- Mohamed Amer
- EPSRC/BBSRC Future Biomanufacturing Research Hub, Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, BBSRC/EPSRC, The University of Manchester, Manchester, M1 7DN, UK
| | - Helen Toogood
- EPSRC/BBSRC Future Biomanufacturing Research Hub, Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, BBSRC/EPSRC, The University of Manchester, Manchester, M1 7DN, UK
| | - Nigel S Scrutton
- EPSRC/BBSRC Future Biomanufacturing Research Hub, Synthetic Biology Research Centre SYNBIOCHEM Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Sciences, BBSRC/EPSRC, The University of Manchester, Manchester, M1 7DN, UK.
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132
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Tian J, Yang G, Gu Y, Sun X, Lu Y, Jiang W. Developing an endogenous quorum-sensing based CRISPRi circuit for autonomous and tunable dynamic regulation of multiple targets in Streptomyces. Nucleic Acids Res 2020; 48:8188-8202. [PMID: 32672817 PMCID: PMC7430639 DOI: 10.1093/nar/gkaa602] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/01/2020] [Accepted: 07/15/2020] [Indexed: 12/12/2022] Open
Abstract
Quorum-sensing (QS) mediated dynamic regulation has emerged as an effective strategy for optimizing product titers in microbes. However, these QS-based circuits are often created on heterologous systems and require careful tuning via a tedious testing/optimization process. This hampers their application in industrial microbes. Here, we design a novel QS circuit by directly integrating an endogenous QS system with CRISPRi (named EQCi) in the industrial rapamycin-producing strain Streptomyces rapamycinicus. EQCi combines the advantages of both the QS system and CRISPRi to enable tunable, autonomous, and dynamic regulation of multiple targets simultaneously. Using EQCi, we separately downregulate three key nodes in essential pathways to divert metabolic flux towards rapamycin biosynthesis and significantly increase its titers. Further application of EQCi to simultaneously regulate these three key nodes with fine-tuned repression strength boosts the rapamycin titer by ∼660%, achieving the highest reported titer (1836 ± 191 mg/l). Notably, compared to static engineering strategies, which result in growth arrest and suboptimal rapamycin titers, EQCi-based regulation substantially promotes rapamycin titers without affecting cell growth, indicating that it can achieve a trade-off between essential pathways and product synthesis. Collectively, this study provides a convenient and effective strategy for strain improvement and shows potential for application in other industrial microorganisms.
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Affiliation(s)
- Jinzhong Tian
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences (CAS), Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Gaohua Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences (CAS), Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Yang Gu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences (CAS), Shanghai 200032, China
| | - Xinqiang Sun
- XinChang Pharmaceutical Factory, Zhejiang medicine LTD, Xinchang 312500, Zhejiang Province, China
| | - Yinhua Lu
- College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Weihong Jiang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences (CAS), Shanghai 200032, China
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133
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Ding N, Yuan Z, Zhang X, Chen J, Zhou S, Deng Y. Programmable cross-ribosome-binding sites to fine-tune the dynamic range of transcription factor-based biosensor. Nucleic Acids Res 2020; 48:10602-10613. [PMID: 32976557 PMCID: PMC7544201 DOI: 10.1093/nar/gkaa786] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 11/24/2022] Open
Abstract
Currently, predictive translation tuning of regulatory elements to the desired output of transcription factor (TF)-based biosensors remains a challenge. The gene expression of a biosensor system must exhibit appropriate translation intensity, which is controlled by the ribosome-binding site (RBS), to achieve fine-tuning of its dynamic range (i.e. fold change in gene expression between the presence and absence of inducer) by adjusting the translation level of the TF and reporter. However, existing TF-based biosensors generally suffer from unpredictable dynamic range. Here, we elucidated the connections and partial mechanisms between RBS, translation level, protein folding and dynamic range, and presented a design platform that predictably tuned the dynamic range of biosensors based on deep learning of large datasets cross-RBSs (cRBSs). In doing so, a library containing 7053 designed cRBSs was divided into five sub-libraries through fluorescence-activated cell sorting to establish a classification model based on convolutional neural network in deep learning. Finally, the present work exhibited a powerful platform to enable predictable translation tuning of RBS to the dynamic range of biosensors.
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Affiliation(s)
- Nana Ding
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, People's Republic of China
| | - Zhenqi Yuan
- School of Internet of Things Engineering, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, People's Republic of China.,Engineering Research Center of Internet of Things Technology Applications, Ministry of Education, Wuxi 214122, People's Republic of China
| | - Xiaojuan Zhang
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, People's Republic of China
| | - Jing Chen
- School of Internet of Things Engineering, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, People's Republic of China.,Engineering Research Center of Internet of Things Technology Applications, Ministry of Education, Wuxi 214122, People's Republic of China
| | - Shenghu Zhou
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, People's Republic of China
| | - Yu Deng
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, People's Republic of China
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134
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Developing a pathway-independent and full-autonomous global resource allocation strategy to dynamically switching phenotypic states. Nat Commun 2020; 11:5521. [PMID: 33139748 PMCID: PMC7606477 DOI: 10.1038/s41467-020-19432-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 10/14/2020] [Indexed: 11/29/2022] Open
Abstract
A grand challenge of biological chemical production is the competition between synthetic circuits and host genes for limited cellular resources. Quorum sensing (QS)-based dynamic pathway regulations provide a pathway-independent way to rebalance metabolic flux over the course of the fermentation. Most cases, however, these pathway-independent strategies only have capacity for a single QS circuit functional in one cell. Furthermore, current dynamic regulations mainly provide localized control of metabolic flux. Here, with the aid of engineering synthetic orthogonal quorum-related circuits and global mRNA decay, we report a pathway-independent dynamic resource allocation strategy, which allows us to independently controlling two different phenotypic states to globally redistribute cellular resources toward synthetic circuits. The strategy which could pathway-independently and globally self-regulate two desired cell phenotypes including growth and production phenotypes could totally eliminate the need for human supervision of the entire fermentation. A challenge for biological chemical production is the completion between synthetic circuits and host resources. Here the authors the authors use quorum sensing circuits and global mRNA decay to independently control two phenotypic states.
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135
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Li J, Rong L, Zhao Y, Li S, Zhang C, Xiao D, Foo JL, Yu A. Next-generation metabolic engineering of non-conventional microbial cell factories for carboxylic acid platform chemicals. Biotechnol Adv 2020; 43:107605. [DOI: 10.1016/j.biotechadv.2020.107605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 06/30/2020] [Accepted: 07/27/2020] [Indexed: 01/21/2023]
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136
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Ding Q, Diao W, Gao C, Chen X, Liu L. Microbial cell engineering to improve cellular synthetic capacity. Biotechnol Adv 2020; 45:107649. [PMID: 33091485 DOI: 10.1016/j.biotechadv.2020.107649] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/02/2020] [Accepted: 10/13/2020] [Indexed: 01/21/2023]
Abstract
Rapid technological progress in gene assembly, biosensors, and genetic circuits has led to reinforce the cellular synthetic capacity for chemical production. However, overcoming the current limitations of these techniques in maintaining cellular functions and enhancing the cellular synthetic capacity (e.g., catalytic efficiency, strain performance, and cell-cell communication) remains challenging. In this review, we propose a strategy for microbial cell engineering to improve the cellular synthetic capacity by utilizing biotechnological tools along with system biology methods to regulate cellular functions during chemical production. Current strategies in microbial cell engineering are mainly focused on the organelle, cell, and consortium levels. This review highlights the potential of using biotechnology to further develop the field of microbial cell engineering and provides guidance for utilizing microorganisms as attractive regulation targets.
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Affiliation(s)
- Qiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Wenwen Diao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
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137
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Tang RQ, Wagner JM, Alper HS, Zhao XQ, Bai FW. Design, Evolution, and Characterization of a Xylose Biosensor in Escherichia coli Using the XylR/ xylO System with an Expanded Operating Range. ACS Synth Biol 2020; 9:2714-2722. [PMID: 32886884 DOI: 10.1021/acssynbio.0c00225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Genetically encoded biosensors are extensively utilized in synthetic biology and metabolic engineering. However, reported xylose biosensors are far too sensitive with a limited operating range to be useful for most sensing applications. In this study, we describe directed evolution of Escherichia coli XylR, and construction of biosensors based on XylR and the corresponding operator xylO. The operating range of biosensors containing the mutant XylR was increased by nearly 10-fold comparing with the control. Two individual amino acid mutations (either L73P or N220T) in XylR were sufficient to extend the linear response range to upward of 10 g/L xylose. The evolved biosensors described here are well suited for developing whole-cell biosensors for detecting varying xylose concentrations across an expanded range. As an alternative use of this system, we also demonstrate the utility of XylR and xylO as a xylose inducible system to enable graded gene expression through testing with β-galactosidase gene and the lycopene synthetic pathway. This evolution strategy identified a less-sensitive biosensor for real applications, thus providing new insights into strategies for expanding operating ranges of other biosensors for synthetic biology applications.
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Affiliation(s)
- Rui-Qi Tang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - James M. Wagner
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Hal S. Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Xin-Qing Zhao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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138
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Zou D, Maina SW, Zhang F, Yan Z, Ding L, Shao Y, Xin Z. Mining New Plipastatins and Increasing the Total Yield Using CRISPR/Cas9 in Genome-Modified Bacillus subtilis 1A751. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:11358-11367. [PMID: 32930578 DOI: 10.1021/acs.jafc.0c03694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CRISPR/Cas9 is one of the robust and effective gene manipulation tools which has been widely applied in various organisms. In this study, the plipastatin gene cluster was successfully expressed in genome-modified Bacillus subtilis 1A751 by disrupting the surfactin operon (srf) through CRISPR/Cas9 technology. The presumed plipastatin biosynthetic pathway was proposed based on the analysis of its biosynthetic gene cluster. Two new plipastatins were identified by a combination of ultra-high performance liquid chromatography-coupled electron spray ionization-tandem mass spectrometry and gas chromatography-mass spectrometry analyses, together with nine known plipastatins or their derivatives. The yield of plipastatin was as high as 1600 mg/L which is the highest reported to date. Antimicrobial experiments revealed that its methanolic extracts exhibited powerful inhibitory effects on the growth of the tested pathogens and fungi. The results from this investigation highlight the remarkable utility of CRISPR/Cas9 in mining new plipastatins and increasing the total plipastatin yield, providing a new pipeline for the industrial application of plipastatin.
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Affiliation(s)
- Dandan Zou
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Sarah Wanjiku Maina
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Fengmin Zhang
- Testing Center, Yangzhou University, Wenhui East Road 48, Yangzhou 225009, China
| | - Zhenzhen Yan
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Liping Ding
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Yuting Shao
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China
| | - Zhihong Xin
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China
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139
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Dinh CV, Prather KLJ. Layered and multi-input autonomous dynamic control strategies for metabolic engineering. Curr Opin Biotechnol 2020; 65:156-162. [DOI: 10.1016/j.copbio.2020.02.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 10/24/2022]
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140
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Carrasco-López C, García-Echauri SA, Kichuk T, Avalos JL. Optogenetics and biosensors set the stage for metabolic cybergenetics. Curr Opin Biotechnol 2020; 65:296-309. [DOI: 10.1016/j.copbio.2020.07.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/23/2020] [Accepted: 07/25/2020] [Indexed: 12/17/2022]
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141
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Tan S, Shi F, Liu H, Yu X, Wei S, Fan Z, Li Y. Dynamic Control of 4-Hydroxyisoleucine Biosynthesis by Modified l-Isoleucine Biosensor in Recombinant Corynebacterium glutamicum. ACS Synth Biol 2020; 9:2378-2389. [PMID: 32813974 DOI: 10.1021/acssynbio.0c00127] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
4-Hydroxyisoleucine (4-HIL), a promising drug for treating diabetes, can be synthesized from the self-produced l-isoleucine (Ile) by expressing the Ile dioxygenase gene ido in Corynebacterium glutamicum. However, the requirement of three substrates, Ile, α-ketoglutarate (α-KG), and O2, makes such de novo biosynthesis difficult to be fulfilled effectively under static engineering conditions. In this study, dynamic control of 4-HIL biosynthesis by the Ile biosensor Lrp-PbrnFE was researched. The native PbrnFE promoter of natural Ile biosensor was still weak even under Ile induction. Through tetA dual genetic selection, several modified stronger PbrnFEN promoters were obtained from the synthetic library of the Ile biosensor. Dynamic regulation of ido expression by modified Ile biosensors increased the 4-HIL titer from 24.7 mM to 28.9-74.4 mM. The best strain ST04 produced even a little more 4-HIL than the static strain SN02 overexpressing ido by the strong PtacM promoter (69.7 mM). Further dynamic modulation of α-KG supply in ST04 by expressing different PbrnFEN-controlled odhI decreased the 4-HIL production but increased the l-glutamate or Ile accumulation. However, synergistic modulation of α-KG supply and O2 supply in ST04 by different combinations of PbrnFEN-odhI and PbrnFEN-vgb improved the 4-HIL production significantly, and the highest titer (135.3 mM) was obtained in ST17 strain regulating all the three genes by PbrnFE7. This titer was higher than those of all the static metabolic engineered C. glutamicum strains ever constructed. Therefore, dynamic regulation by modified Ile biosensor is a predominant strategy for enhancing 4-HIL de novo biosynthesis in C. glutamicum.
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Affiliation(s)
- Shuyu Tan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Feng Shi
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Haiyan Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xinping Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Shuyu Wei
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhengyu Fan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yongfu Li
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
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142
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Park MR, Chen Y, Thompson M, Benites VT, Fong B, Petzold CJ, Baidoo EEK, Gladden JM, Adams PD, Keasling JD, Simmons BA, Singer SW. Response of Pseudomonas putida to Complex, Aromatic-Rich Fractions from Biomass. CHEMSUSCHEM 2020; 13:4455-4467. [PMID: 32160408 DOI: 10.1002/cssc.202000268] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/11/2020] [Indexed: 06/10/2023]
Abstract
There is strong interest in the valorization of lignin to produce valuable products; however, its structural complexity has been a conversion bottleneck. Chemical pretreatment liberates lignin-derived soluble fractions that may be upgraded by bioconversion. Cholinium ionic liquid pretreatment of sorghum produced soluble, aromatic-rich fractions that were converted by Pseudomonas putida (P. putida), a promising host for aromatic bioconversion. Growth studies and mutational analysis demonstrated that P. putida growth on these fractions was dependent on aromatic monomers but unknown factors also contributed. Proteomic and metabolomic analyses indicated that these unknown factors were amino acids and residual ionic liquid; the oligomeric aromatic fraction derived from lignin was not converted. A cholinium catabolic pathway was identified, and the deletion of the pathway stopped the ability of P. putida to grow on cholinium ionic liquid. This work demonstrates that aromatic-rich fractions obtained through pretreatment contain multiple substrates; conversion strategies should account for this complexity.
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Affiliation(s)
- Mee-Rye Park
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yan Chen
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Mitchell Thompson
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Veronica T Benites
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Bonnie Fong
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Christopher J Petzold
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Edward E K Baidoo
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John M Gladden
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biomass Science and Conversion Technology, Sandia National Laboratories, 7011 East Avenue, Livermore, CA, 94551, USA
| | - Paul D Adams
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Jay D Keasling
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
- Center for Biosustainability, Danish Technical University, Lyngby, Denmark
- Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes for Advanced Technology, Shenzhen, China
| | - Blake A Simmons
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Steven W Singer
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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143
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A kinetic rationale for functional redundancy in fatty acid biosynthesis. Proc Natl Acad Sci U S A 2020; 117:23557-23564. [PMID: 32883882 DOI: 10.1073/pnas.2013924117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells build fatty acids with biocatalytic assembly lines in which a subset of enzymes often exhibit overlapping activities (e.g., two enzymes catalyze one or more identical reactions). Although the discrete enzymes that make up fatty acid pathways are well characterized, the importance of catalytic overlap between them is poorly understood. We developed a detailed kinetic model of the fatty acid synthase (FAS) of Escherichia coli and paired that model with a fully reconstituted in vitro system to examine the capabilities afforded by functional redundancy in fatty acid synthesis. The model captures-and helps explain-the effects of experimental perturbations to FAS systems and provides a powerful tool for guiding experimental investigations of fatty acid assembly. Compositional analyses carried out in silico and in vitro indicate that FASs with multiple partially redundant enzymes enable tighter (i.e., more independent and/or broader range) control of distinct biochemical objectives-the total production, unsaturated fraction, and average length of fatty acids-than FASs with only a single multifunctional version of each enzyme (i.e., one enzyme with the catalytic capabilities of two partially redundant enzymes). Maximal production of unsaturated fatty acids, for example, requires a second dehydratase that is not essential for their synthesis. This work provides a kinetic, control-theoretic rationale for the inclusion of partially redundant enzymes in fatty acid pathways and supplies a valuable framework for carrying out detailed studies of FAS kinetics.
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144
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Rewiring carbon flux in Escherichia coli using a bifunctional molecular switch. Metab Eng 2020; 61:47-57. [DOI: 10.1016/j.ymben.2020.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/29/2020] [Accepted: 05/03/2020] [Indexed: 12/21/2022]
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145
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Wiechert J, Gätgens C, Wirtz A, Frunzke J. Inducible Expression Systems Based on Xenogeneic Silencing and Counter-Silencing and Design of a Metabolic Toggle Switch. ACS Synth Biol 2020; 9:2023-2038. [PMID: 32649183 DOI: 10.1021/acssynbio.0c00111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inducible expression systems represent key modules in regulatory circuit design and metabolic engineering approaches. However, established systems are often limited in terms of applications due to high background expression levels and inducer toxicity. In bacteria, xenogeneic silencing (XS) proteins are involved in the tight control of horizontally acquired, AT-rich DNA. The action of XS proteins may be opposed by interference with a specific transcription factor, resulting in the phenomenon of counter-silencing, thereby activating gene expression. In this study, we harnessed this principle for the construction of a synthetic promoter library consisting of phage promoters targeted by the Lsr2-like XS protein CgpS of Corynebacterium glutamicum. Counter-silencing was achieved by inserting the operator sequence of the gluconate-responsive transcription factor GntR. The GntR-dependent promoter library is comprised of 28 activated and 16 repressed regulatory elements featuring effector-dependent tunability. For selected candidates, background expression levels were confirmed to be significantly reduced in comparison to established heterologous expression systems. Finally, a GntR-dependent metabolic toggle switch was implemented in a C. glutamicum l-valine production strain allowing the dynamic redirection of carbon flux between biomass and product formation.
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Affiliation(s)
- Johanna Wiechert
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Cornelia Gätgens
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Astrid Wirtz
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Julia Frunzke
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, 52425 Jülich, Germany
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146
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Dasgupta A, Chowdhury N, De RK. Metabolic pathway engineering: Perspectives and applications. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 192:105436. [PMID: 32199314 DOI: 10.1016/j.cmpb.2020.105436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 02/29/2020] [Accepted: 03/03/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Metabolic engineering aims at contriving microbes as biocatalysts for enhanced and cost-effective production of countless secondary metabolites. These secondary metabolites can be treated as the resources of industrial chemicals, pharmaceuticals and fuels. Plants are also crucial targets for metabolic engineers to produce necessary secondary metabolites. Metabolic engineering of both microorganism and plants also contributes towards drug discovery. In order to implement advanced metabolic engineering techniques efficiently, metabolic engineers should have detailed knowledge about cell physiology and metabolism. Principle behind methodologies: Genome-scale mathematical models of integrated metabolic, signal transduction, gene regulatory and protein-protein interaction networks along with experimental validation can provide such knowledge in this context. Incorporation of omics data into these models is crucial in the case of drug discovery. Inverse metabolic engineering and metabolic control analysis (MCA) can help in developing such models. Artificial intelligence methodology can also be applied for efficient and accurate metabolic engineering. CONCLUSION In this review, we discuss, at the beginning, the perspectives of metabolic engineering and its application on microorganism and plant leading to drug discovery. At the end, we elaborate why inverse metabolic engineering and MCA are closely related to modern metabolic engineering. In addition, some crucial steps ensuring efficient and optimal metabolic engineering strategies have been discussed. Moreover, we explore the use of genomics data for the activation of silent metabolic clusters and how it can be integrated with metabolic engineering. Finally, we exhibit a few applications of artificial intelligence to metabolic engineering.
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Affiliation(s)
- Abhijit Dasgupta
- Department of Data Science, School of Interdisciplinary Studies, University of Kalyani, Kalyani, Nadia 741235, West Bengal, India
| | - Nirmalya Chowdhury
- Department of Computer Science & Engineering, Jadavpur University, Kolkata 700032, India
| | - Rajat K De
- Machine Intelligence Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata 700108, India.
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147
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Recent advances in improving metabolic robustness of microbial cell factories. Curr Opin Biotechnol 2020; 66:69-77. [PMID: 32683192 DOI: 10.1016/j.copbio.2020.06.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/12/2020] [Accepted: 06/17/2020] [Indexed: 12/20/2022]
Abstract
Engineering microbial cell factories has been widely applied to produce compounds spanning from intricate natural products to bulk commodities. In each case, host robustness is essential to ensure the reliable and sustainable production of targeted metabolites. However, it can be negatively affected by metabolic burden, pathway toxicity, and harsh environment, resulting in a decreased titer and productivity. Enhanced robustness enables host to have better production performance under complicated growth circumstances. Here, we review current strategies for boosting host robustness, including metabolic balancing, genetic and phenotype stability enhancement, and tolerance engineering. In addition, we discuss the challenges and future perspectives on microbial host engineering for increased robustness.
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148
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Rational flux-tuning of Halomonas bluephagenesis for co-production of bioplastic PHB and ectoine. Nat Commun 2020; 11:3313. [PMID: 32620759 PMCID: PMC7334215 DOI: 10.1038/s41467-020-17223-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/16/2020] [Indexed: 11/21/2022] Open
Abstract
Ectoine, a compatible solute synthesized by many halophiles for hypersalinity resistance, has been successfully produced by metabolically engineered Halomonas bluephagenesis, which is a bioplastic poly(3-hydroxybutyrate) producer allowing open unsterile and continuous conditions. Here we report a de novo synthesis pathway for ectoine constructed into the chromosome of H. bluephagenesis utilizing two inducible systems, which serve to fine-tune the transcription levels of three clusters related to ectoine synthesis, including ectABC, lysC and asd based on a GFP-mediated transcriptional tuning approach. Combined with bypasses deletion, the resulting recombinant H. bluephagenesis TD-ADEL-58 is able to produce 28 g L−1 ectoine during a 28 h fed-batch growth process. Co-production of ectoine and PHB is achieved to 8 g L−1 ectoine and 32 g L−1 dry cell mass containing 75% PHB after a 44 h growth. H. bluephagenesis demonstrates to be a suitable co-production chassis for polyhydroxyalkanoates and non-polymer chemicals such as ectoine. Halomonas bluephagenesis is a halophilic platform bacterium for next generation industrial biotechnology. Here, the authors employ a stimulus response-based flux-tuning method for coproduction of bioplastic PHB and ectoine under open unsterile and continuous growth conditions.
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149
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Common problems associated with the microbial productions of aromatic compounds and corresponding metabolic engineering strategies. Biotechnol Adv 2020; 41:107548. [DOI: 10.1016/j.biotechadv.2020.107548] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 01/06/2023]
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150
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Engineered dynamic distribution of malonyl-CoA flux for improving polyketide biosynthesis in Komagataella phaffii. J Biotechnol 2020; 320:80-85. [PMID: 32574793 DOI: 10.1016/j.jbiotec.2020.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/27/2020] [Accepted: 06/16/2020] [Indexed: 12/29/2022]
Abstract
Malonyl-CoA is a basic but limited precursor for the biosynthesis of various bioactive compounds and life-supporting fatty acids in cells. This study develops a biosynthetic system to dynamically redirect malonyl-CoA flux and improve production of malonyl-CoA derived polyketide (6-MSA) in Komagataella phaffii. A synthetic regulatory protein fusing a yeast activator Prm1 with a bacterial repressor FapR was proved to work with a hybrid promoter (-7)fapO-cPAOX1 and activate gene expression. Expression mode by the Prm1-FapR/(-7)fapO-cPAOX1 device was not affected by intracellular malonyl-CoA levels. Further, 9 promoter variants of PGAP with insertion of fapO at various sites were tested with the Prm1-FapR. It generated a biosensor of Prm1-FapR/PGAP-(+2)fapO with regulation behavior of malonyl-CoA-low-level repression/high-level derepression. Both devices were subsequently integrated into a single cell, for which fatty acid synthesis module was driven by Prm1-FapR/PGAP-(+2)fapO but 6-MSA synthesis module was expressed by Prm1-FapR/(-7)fapO-cPAOX1. The integrated system allowed continuous polyketide synthesis but malonyl-CoA-high-level "on"/low-level "off" fatty acid synthesis. This design finally increased 6-MSA production capacity by 260 %, proving the positive effects of dynamic malonyl-CoA distribution to the target compounds. It provides a new strategy for synthesis of malonyl-CoA derived compounds in eukaryotic chassis hosts.
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