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van Rosmalen R, Moreno-Paz S, Duman-Özdamar Z, Suarez-Diez M. CFSA: Comparative flux sampling analysis as a guide for strain design. Metab Eng Commun 2024; 19:e00244. [PMID: 39072282 PMCID: PMC11283130 DOI: 10.1016/j.mec.2024.e00244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 07/30/2024] Open
Abstract
Genome-scale metabolic models of microbial metabolism have extensively been used to guide the design of microbial cell factories, still, many of the available strain design algorithms often fail to produce a reduced list of targets for improved performance that can be implemented and validated in a step-wise manner. We present Comparative Flux Sampling Analysis (CFSA), a strain design method based on the extensive comparison of complete metabolic spaces corresponding to maximal or near-maximal growth and production phenotypes. The comparison is complemented by statistical analysis to identify reactions with altered flux that are suggested as targets for genetic interventions including up-regulations, down-regulations and gene deletions. We applied CFSA to the production of lipids by Cutaneotrichosporon oleaginosus and naringenin by Saccharomyces cerevisiae identifying engineering targets in agreement with previous studies as well as new interventions. CFSA is an easy-to-use, robust method that suggests potential metabolic engineering targets for growth-uncoupled production that can be applied to the design of microbial cell factories.
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Affiliation(s)
| | | | - Z.E. Duman-Özdamar
- Laboratory of Systems and Synthetic Biology, Stippeneng 4 6708 WE Wageningen, the Netherlands
| | - M. Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Stippeneng 4 6708 WE Wageningen, the Netherlands
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2
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Lara AR, Kunert F, Vandenbroucke V, Taymaz-Nikerel H, Martínez LM, Sigala JC, Delvigne F, Gosset G, Büchs J. Transport-controlled growth decoupling for self-induced protein expression with a glycerol-repressible genetic circuit. Biotechnol Bioeng 2024; 121:1789-1802. [PMID: 38470342 DOI: 10.1002/bit.28697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/17/2024] [Accepted: 03/01/2024] [Indexed: 03/13/2024]
Abstract
Decoupling cell formation from recombinant protein synthesis is a potent strategy to intensify bioprocesses. Escherichia coli strains with mutations in the glucose uptake components lack catabolite repression, display low growth rate, no overflow metabolism, and high recombinant protein yields. Fast growth rates were promoted by the simultaneous consumption of glucose and glycerol, and this was followed by a phase of slow growth, when only glucose remained in the medium. A glycerol-repressible genetic circuit was designed to autonomously induce recombinant protein expression. The engineered strain bearing the genetic circuit was cultured in 3.9 g L-1 glycerol + 18 g L-1 glucose in microbioreactors with online oxygen transfer rate monitoring. The growth was fast during the simultaneous consumption of both carbon sources (C-sources), while expression of the recombinant protein was low. When glycerol was depleted, the growth rate decreased, and the specific fluorescence reached values 17% higher than those obtained with a strong constitutive promoter. Despite the relatively high amount of C-source used, no oxygen limitation was observed. The proposed approach eliminates the need for the substrate feeding or inducers addition and is set as a simple batch culture while mimicking fed-batch performance.
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Affiliation(s)
- Alvaro R Lara
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
| | - Flavio Kunert
- Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Aachen, Germany
| | - Vincent Vandenbroucke
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Hilal Taymaz-Nikerel
- Department of Genetics and Bioengineering, Istanbul Bilgi University, Istanbul, Turkey
| | - Luz María Martínez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Juan-Carlos Sigala
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Ciudad de México, México
| | - Frank Delvigne
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Guillermo Gosset
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Jochen Büchs
- Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Aachen, Germany
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3
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Arboleda-García A, Alarcon-Ruiz I, Boada-Acosta L, Boada Y, Vignoni A, Jantus-Lewintre E. Advancements in synthetic biology-based bacterial cancer therapy: A modular design approach. Crit Rev Oncol Hematol 2023; 190:104088. [PMID: 37541537 DOI: 10.1016/j.critrevonc.2023.104088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/18/2023] [Accepted: 07/31/2023] [Indexed: 08/06/2023] Open
Abstract
Synthetic biology aims to program living bacteria cells with artificial genetic circuits for user-defined functions, transforming them into powerful tools with numerous applications in various fields, including oncology. Cancer treatments have serious side effects on patients due to the systemic action of the drugs involved. To address this, new systems that provide localized antitumoral action while minimizing damage to healthy tissues are required. Bacteria, often considered pathogenic agents, have been used as cancer treatments since the early 20th century. Advances in genetic engineering, synthetic biology, microbiology, and oncology have improved bacterial therapies, making them safer and more effective. Here we propose six modules for a successful synthetic biology-based bacterial cancer therapy, the modules include Payload, Release, Tumor-targeting, Biocontainment, Memory, and Genetic Circuit Stability Module. These will ensure antitumor activity, safety for the environment and patient, prevent bacterial colonization, maintain cell stability, and prevent loss or defunctionalization of the genetic circuit.
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Affiliation(s)
- Andrés Arboleda-García
- Systems Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, Spain
| | - Ivan Alarcon-Ruiz
- Gene Regulation in Cardiovascular Remodeling and Inflammation Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lissette Boada-Acosta
- Centro de Investigación Biomédica en Red Cáncer, CIBERONC, Madrid, Spain; TRIAL Mixed Unit, Centro de Investigación Príncipe Felipe-Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain; Molecular Oncology Laboratory, Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain
| | - Yadira Boada
- Systems Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, Spain
| | - Alejandro Vignoni
- Systems Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, Spain.
| | - Eloisa Jantus-Lewintre
- Centro de Investigación Biomédica en Red Cáncer, CIBERONC, Madrid, Spain; TRIAL Mixed Unit, Centro de Investigación Príncipe Felipe-Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain; Molecular Oncology Laboratory, Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain; Department of Biotechnology, Universitat Politècnica de València, Valencia, Spain
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4
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Ding Q, Ye C. Microbial engineering for shikimate biosynthesis. Enzyme Microb Technol 2023; 170:110306. [PMID: 37598506 DOI: 10.1016/j.enzmictec.2023.110306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/03/2023] [Accepted: 08/14/2023] [Indexed: 08/22/2023]
Abstract
Shikimate, a precursor to the antiviral drug oseltamivir (Tamiflu®), can influence aromatic metabolites and finds extensive use in antimicrobial, antitumor, and cardiovascular applications. Consequently, various strategies have been developed for chemical synthesis and plant extraction to enhance shikimate biosynthesis, potentially impacting environmental conditions, economic sustainability, and separation and purification processes. Microbial engineering has been developed as an environmentally friendly approach for shikimate biosynthesis. In this review, we provide a comprehensive summary of microbial strategies for shikimate biosynthesis. These strategies primarily include chassis construction, biochemical optimization, pathway remodelling, and global regulation. Furthermore, we discuss future perspectives on shikimate biosynthesis and emphasize the importance of utilizing advanced metabolic engineering tools to regulate microbial networks for constructing robust microbial cell factories.
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Affiliation(s)
- Qiang Ding
- School of Life Sciences, Anhui University, Hefei 230601, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China; Anhui Key Laboratory of Modern Biomanufacturing, Hefei 230601, Anhui, China
| | - Chao Ye
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China.
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5
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Eng T, Banerjee D, Menasalvas J, Chen Y, Gin J, Choudhary H, Baidoo E, Chen JH, Ekman A, Kakumanu R, Diercks YL, Codik A, Larabell C, Gladden J, Simmons BA, Keasling JD, Petzold CJ, Mukhopadhyay A. Maximizing microbial bioproduction from sustainable carbon sources using iterative systems engineering. Cell Rep 2023; 42:113087. [PMID: 37665664 DOI: 10.1016/j.celrep.2023.113087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/10/2023] [Accepted: 08/18/2023] [Indexed: 09/06/2023] Open
Abstract
Maximizing the production of heterologous biomolecules is a complex problem that can be addressed with a systems-level understanding of cellular metabolism and regulation. Specifically, growth-coupling approaches can increase product titers and yields and also enhance production rates. However, implementing these methods for non-canonical carbon streams is challenging due to gaps in metabolic models. Over four design-build-test-learn cycles, we rewire Pseudomonas putida KT2440 for growth-coupled production of indigoidine from para-coumarate. We explore 4,114 potential growth-coupling solutions and refine one design through laboratory evolution and ensemble data-driven methods. The final growth-coupled strain produces 7.3 g/L indigoidine at 77% maximum theoretical yield in para-coumarate minimal medium. The iterative use of growth-coupling designs and functional genomics with experimental validation was highly effective and agnostic to specific hosts, carbon streams, and final products and thus generalizable across many systems.
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Affiliation(s)
- Thomas Eng
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Deepanwita Banerjee
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Javier Menasalvas
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yan Chen
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jennifer Gin
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Hemant Choudhary
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biomanufacturing and Biomaterials Department, Sandia National Laboratories, Livermore, CA, USA
| | - Edward Baidoo
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jian Hua Chen
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA; National Center for X-ray Tomography, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Axel Ekman
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA; National Center for X-ray Tomography, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ramu Kakumanu
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yuzhong Liu Diercks
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alex Codik
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Carolyn Larabell
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA; National Center for X-ray Tomography, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - John Gladden
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biomanufacturing and Biomaterials Department, Sandia National Laboratories, Livermore, CA, USA
| | - Blake A Simmons
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jay D Keasling
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; QB3 Institute, University of California, Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, USA; Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University Denmark, 2970 Horsholm, Denmark; Synthetic Biochemistry Center, Institute for Synthetic Biology, Shenzhen Institutes for Advanced Technologies, Shenzhen, China
| | - Christopher J Petzold
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Aindrila Mukhopadhyay
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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6
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Assessing and reducing phenotypic instability in cyanobacteria. Curr Opin Biotechnol 2023; 80:102899. [PMID: 36724584 DOI: 10.1016/j.copbio.2023.102899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/23/2022] [Accepted: 01/06/2023] [Indexed: 01/31/2023]
Abstract
Cyanobacteria have promising potential as sustainable cell factories. However, one challenge that is still largely unreported in scaling-up cyanobacteria bioproduction is phenotypic instability, where the emergence and selection of nonproducing cells leading to loss in production has longer evolutionary timescales to take place in industrial-scale bioreactors. Quantifying phenotypic instability early on in strain development allows researchers to make informed decisions on whether to proceed with scalable designs, or if present, devise countermeasures to reduce instability. One particularly effective strategy to mitigate instability is the use of genome-scale metabolic models to design growth-coupled production strains. In silico studies have predicted that creating certain cofactor imbalances or removing recycling reactions in cyanobacteria can be exploited to stably produce a wide variety of metabolites.
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7
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Ye JW, Lin YN, Yi XQ, Yu ZX, Liu X, Chen GQ. Synthetic biology of extremophiles: a new wave of biomanufacturing. Trends Biotechnol 2023; 41:342-357. [PMID: 36535816 DOI: 10.1016/j.tibtech.2022.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/12/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022]
Abstract
Microbial biomanufacturing, powered by the advances of synthetic biology, has attracted growing interest for the production of diverse products. In contrast to conventional microbes, extremophiles have shown better performance for low-cost production owing to their outstanding growth and synthesis capacity under stress conditions, allowing unsterilized fermentation processes. We review increasing numbers of products already manufactured utilizing extremophiles in recent years. In addition, genetic parts, molecular tools, and manipulation approaches for extremophile engineering are also summarized, and challenges and opportunities are predicted for non-conventional chassis. Next-generation industrial biotechnology (NGIB) based on engineered extremophiles promises to simplify biomanufacturing processes and achieve open and continuous fermentation, without sterilization, and utilizing low-cost substrates, making NGIB an attractive green process for sustainable manufacturing.
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Affiliation(s)
- Jian-Wen Ye
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China; Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China; Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Yi-Na Lin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China; Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China; Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Xue-Qing Yi
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhuo-Xuan Yu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Xu Liu
- PhaBuilder Biotech Company, Shunyi District, Zhaoquan Ying, Beijing 101309, China
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; Ministry of Education (MOE) Laboratory of Industrial Biocatalysis, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing, China.
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8
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He H, Li Y, Zhang L, Ding Z, Shi G. Understanding and application of Bacillus nitrogen regulation: A synthetic biology perspective. J Adv Res 2022:S2090-1232(22)00205-3. [PMID: 36103961 DOI: 10.1016/j.jare.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 08/22/2022] [Accepted: 09/05/2022] [Indexed: 10/14/2022] Open
Abstract
BACKGROUND Nitrogen sources play an essential role in maintaining the physiological and biochemical activity of bacteria. Nitrogen metabolism, which is the core of microorganism metabolism, makes bacteria able to autonomously respond to different external nitrogen environments by exercising complex internal regulatory networks to help them stay in an ideal state. Although various studies have been put forth to better understand this regulation in Bacillus, and many valuable viewpoints have been obtained, these views need to be presented systematically and their possible applications need to be specified. AIM OF REVIEW The intention is to provide a deep and comprehensive understanding of nitrogen metabolism in Bacillus, an important industrial microorganism, and thereby apply this regulatory logic to synthetic biology to improve biosynthesis competitiveness. In addition, the potential researches in the future are also discussed. KEY SCIENTIFIC CONCEPT OF REVIEW Understanding the meticulous regulation process of nitrogen metabolism in Bacillus not only could facilitate research on metabolic engineering but also could provide constructive insights and inspiration for studies of other microorganisms.
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Affiliation(s)
- Hehe He
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China
| | - Youran Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China.
| | - Liang Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China
| | - Zhongyang Ding
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China
| | - Guiyang Shi
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, PR China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, PR China.
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9
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Li X, Jiang W, Qi Q, Liang Q. A Gene Circuit Combining the Endogenous I-E Type CRISPR-Cas System and a Light Sensor to Produce Poly-β-Hydroxybutyric Acid Efficiently. BIOSENSORS 2022; 12:bios12080642. [PMID: 36005038 PMCID: PMC9405541 DOI: 10.3390/bios12080642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/08/2022] [Accepted: 08/12/2022] [Indexed: 11/23/2022]
Abstract
‘Metabolic burden,’ which arises when introducing exogenic synthesizing pathways into a host strain, remains a challenging issue in metabolic engineering. Redirecting metabolic flux from cell growth to product synthesis at an appropriate culture timepoint is ideal for resolving this issue. In this report, we introduce optogenetics—which is capable of precise temporal and spatial control—as a genetic switch, accompanied by the endogenous type I-E CRISPRi system in Escherichia coli (E. coli) to generate a metabolic platform that redirects metabolic flux. Poly-β-hydroxybutyric acid (PHB) production was taken as an example to demonstrate the performance of this platform. A two-to-three-fold increase in PHB content was observed under green light when compared with the production of PHB under red light, confirming the regulatory activity of this platform and its potential to redirect metabolic flux to synthesize target products.
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Affiliation(s)
- Xiaomeng Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, China
- The Second Laboratory of Lanzhou Institute of Biological Products Co., Ltd., No. 888, Yanchang Road, Lanzhou 730046, China
| | - Wei Jiang
- Research Center of Basic Medicine, Central Hospital Affiliated to Shandong First Medical University, No. 105, Jiefang Road, Jinan 250013, China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, China
| | - Quanfeng Liang
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, China
- Correspondence: ; Tel.: +86-13573163779
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10
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Hartline CJ, Zhang F. The Growth Dependent Design Constraints of Transcription-Factor-Based Metabolite Biosensors. ACS Synth Biol 2022; 11:2247-2258. [PMID: 35700119 PMCID: PMC9994378 DOI: 10.1021/acssynbio.2c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolite biosensors based on metabolite-responsive transcription factors are key synthetic biology components for sensing and precisely controlling cellular metabolism. Biosensors are often designed under laboratory conditions but are deployed in applications where cellular growth rate differs drastically from its initial characterization. Here we asked how growth rate impacts the minimum and maximum biosensor outputs and the dynamic range, which are key metrics of biosensor performance. Using LacI, TetR, and FadR-based biosensors in Escherichia coli as models, we find that the dynamic range of different biosensors have different growth rate dependencies. We developed a kinetic model to explore how tuning biosensor parameters impact the dynamic range growth rate dependence. Our modeling and experimental results revealed that the effects to dynamic range and its growth rate dependence are often coupled, and the metabolite transport mechanisms shape the dynamic range-growth rate response. This work provides a systematic understanding of biosensor performance under different growth rates, which will be useful for predicting biosensor behavior in broad synthetic biology and metabolic engineering applications.
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Affiliation(s)
- Christopher J Hartline
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States.,Division of Biology & Biomedical Sciences, Washington University in St. Louis, Saint Louis, Missouri 63130, United States.,Institute of Materials Science & Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
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11
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Liu J, Wang X, Dai G, Zhang Y, Bian X. Microbial chassis engineering drives heterologous production of complex secondary metabolites. Biotechnol Adv 2022; 59:107966. [PMID: 35487394 DOI: 10.1016/j.biotechadv.2022.107966] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 12/27/2022]
Abstract
The cryptic secondary metabolite biosynthetic gene clusters (BGCs) far outnumber currently known secondary metabolites. Heterologous production of secondary metabolite BGCs in suitable chassis facilitates yield improvement and discovery of new-to-nature compounds. The two juxtaposed conventional model microorganisms, Escherichia coli, Saccharomyces cerevisiae, have been harnessed as microbial chassis to produce a bounty of secondary metabolites with the help of certain host engineering. In last decade, engineering non-model microbes to efficiently biosynthesize secondary metabolites has received increasing attention due to their peculiar advantages in metabolic networks and/or biosynthesis. The state-of-the-art synthetic biology tools lead the way in operating genetic manipulation in non-model microorganisms for phenotypic optimization or yields improvement of desired secondary metabolites. In this review, we firstly discuss the pros and cons of several model and non-model microbial chassis, as well as the importance of developing broader non-model microorganisms as alternative programmable heterologous hosts to satisfy the desperate needs of biosynthesis study and industrial production. Then we highlight the lately advances in the synthetic biology tools and engineering strategies for optimization of non-model microbial chassis, in particular, the successful applications for efficient heterologous production of multifarious complex secondary metabolites, e.g., polyketides, nonribosomal peptides, as well as ribosomally synthesized and post-translationally modified peptides. Lastly, emphasis is on the perspectives of chassis cells development to access the ideal cell factory in the artificial intelligence-driven genome era.
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Affiliation(s)
- Jiaqi Liu
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, PR China; Present address: Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8 1, 66123 Saarbrücken, Germany
| | - Xue Wang
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, PR China
| | - Guangzhi Dai
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, PR China
| | - Youming Zhang
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, PR China
| | - Xiaoying Bian
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, PR China.
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12
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Zhou S, Alper HS, Zhou J, Deng Y. Intracellular biosensor-based dynamic regulation to manipulate gene expression at the spatiotemporal level. Crit Rev Biotechnol 2022; 43:646-663. [PMID: 35450502 DOI: 10.1080/07388551.2022.2040415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The use of intracellular, biosensor-based dynamic regulation strategies to regulate and improve the production of useful compounds have progressed significantly over previous decades. By employing such an approach, it is possible to simultaneously realize high productivity and optimum growth states. However, industrial fermentation conditions contain a mixture of high- and low-performance non-genetic variants, as well as young and aged cells at all growth phases. Such significant individual variations would hinder the precise controlling of metabolic flux at the single-cell level to achieve high productivity at the macroscopic population level. Intracellular biosensors, as the regulatory centers of metabolic networks, can real-time sense intra- and extracellular conditions and, thus, could be synthetically adapted to balance the biomass formation and overproduction of compounds by individual cells. Herein, we highlight advances in the designing and engineering approaches to intracellular biosensors. Then, the spatiotemporal properties of biosensors associated with the distribution of inducers are compared. Also discussed is the use of such biosensors to dynamically control the cellular metabolic flux. Such biosensors could achieve single-cell regulation or collective regulation goals, depending on whether or not the inducer distribution is only intracellular.
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Affiliation(s)
- Shenghu Zhou
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, Wuxi, Jiangsu, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Hal S Alper
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.,McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, Wuxi, Jiangsu, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yu Deng
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, Wuxi, Jiangsu, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, Jiangsu, China
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13
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Komera I, Gao C, Guo L, Hu G, Chen X, Liu L. Bifunctional optogenetic switch for improving shikimic acid production in E. coli. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:13. [PMID: 35418155 PMCID: PMC8822657 DOI: 10.1186/s13068-022-02111-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/28/2022] [Indexed: 12/19/2022]
Abstract
BACKGROUND Biomass formation and product synthesis decoupling have been proven to be promising to increase the titer of desired value add products. Optogenetics provides a potential strategy to develop light-induced circuits that conditionally control metabolic flux redistribution for enhanced microbial production. However, the limited number of light-sensitive proteins available to date hinders the progress of light-controlled tools. RESULTS To address these issues, two optogenetic systems (TPRS and TPAS) were constructed by reprogramming the widely used repressor TetR and protease TEVp to expand the current optogenetic toolkit. By merging the two systems, a bifunctional optogenetic switch was constructed to enable orthogonally regulated gene transcription and protein accumulation. Application of this bifunctional switch to decouple biomass formation and shikimic acid biosynthesis allowed 35 g/L of shikimic acid production in a minimal medium from glucose, representing the highest titer reported to date by E. coli without the addition of any chemical inducers and expensive aromatic amino acids. This titer was further boosted to 76 g/L when using rich medium fermentation. CONCLUSION The cost effective and light-controlled switch reported here provides important insights into environmentally friendly tools for metabolic pathway regulation and should be applicable to the production of other value-add chemicals.
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Affiliation(s)
- Irene Komera
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory On Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory On Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Liang Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory On Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Guipeng Hu
- School of Pharmaceutical Science, Jiangnan University, Wuxi, 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory On Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China. .,International Joint Laboratory On Food Safety, Jiangnan University, Wuxi, 214122, China.
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14
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Ziegler M, Hägele L, Gäbele T, Takors R. CRISPRi enables fast growth followed by stable aerobic pyruvate formation in
Escherichia coli
without auxotrophy. Eng Life Sci 2021; 22:70-84. [PMID: 35140555 PMCID: PMC8811725 DOI: 10.1002/elsc.202100021] [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: 02/15/2021] [Revised: 10/06/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022] Open
Abstract
CRISPR interference (CRISPRi) was applied to enable the aerobic production of pyruvate in Escherichia coli MG1655 under glucose excess conditions by targeting the promoter regions of aceE or pdhR. Knockdown strains were cultivated in aerobic shaking flasks and the influence of inducer concentration and different sgRNA binding sites on the production of pyruvate was measured. Targeting the promoter regions of aceE or pdhR triggered pyruvate production during the exponential phase and reduced expression of aceE. In lab‐scale bioreactor fermentations, an aceE silenced strain successfully produced pyruvate under fully aerobic conditions during the exponential phase, but loss of productivity occurred during a subsequent nitrogen‐limited phase. Targeting the promoter region of pdhR enabled pyruvate production during the growth phase of cultivations, and a continued low‐level accumulation during the nitrogen‐limited production phase. Combinatorial targeting of the promoter regions of both aceE and pdhR in E. coli MG1655 pdCas9 psgRNA_aceE_234_pdhR_329 resulted in the stable aerobic production of pyruvate with non‐growing cells at YP/S = 0.36 ± 0.029 gPyruvate/gGlucose in lab‐scale bioreactors throughout an extended nitrogen‐limited production phase.
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Affiliation(s)
- Martin Ziegler
- Institute of Biochemical Engineering University of Stuttgart Stuttgart Germany
| | - Lorena Hägele
- Institute of Biochemical Engineering University of Stuttgart Stuttgart Germany
| | - Teresa Gäbele
- Institute of Biochemical Engineering University of Stuttgart Stuttgart Germany
| | - Ralf Takors
- Institute of Biochemical Engineering University of Stuttgart Stuttgart Germany
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15
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Ropers D, Couté Y, Faure L, Ferré S, Labourdette D, Shabani A, Trouilh L, Vasseur P, Corre G, Ferro M, Teste MA, Geiselmann J, de Jong H. Multiomics Study of Bacterial Growth Arrest in a Synthetic Biology Application. ACS Synth Biol 2021; 10:2910-2926. [PMID: 34739215 DOI: 10.1021/acssynbio.1c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the scalability of a previously developed growth switch based on external control of RNA polymerase expression. Our results indicate that, in liter-scale bioreactors operating in fed-batch mode, growth-arrested Escherichia coli cells are able to convert glucose to glycerol at an increased yield. A multiomics quantification of the physiology of the cells shows that, apart from acetate production, few metabolic side effects occur. However, a number of specific responses to growth slow-down and growth arrest are launched at the transcriptional level. These notably include the downregulation of genes involved in growth-associated processes, such as amino acid and nucleotide metabolism and translation. Interestingly, the transcriptional responses are buffered at the proteome level, probably due to the strong decrease of the total mRNA concentration after the diminution of transcriptional activity and the absence of growth dilution of proteins. Growth arrest thus reduces the opportunities for dynamically adjusting the proteome composition, which poses constraints on the design of biotechnological production processes but may also avoid the initiation of deleterious stress responses.
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Affiliation(s)
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | | | - Sabrina Ferré
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Delphine Labourdette
- GeT-Biopuces, TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France
| | - Arieta Shabani
- Université Grenoble Alpes, Inria, 38000 Grenoble, France
| | - Lidwine Trouilh
- GeT-Biopuces, TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France
| | | | | | - Myriam Ferro
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Marie-Ange Teste
- GeT-Biopuces, TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France
| | - Johannes Geiselmann
- Université Grenoble Alpes, Inria, 38000 Grenoble, France
- Université Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France
| | - Hidde de Jong
- Université Grenoble Alpes, Inria, 38000 Grenoble, France
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16
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Torres‐Bacete J, Luís García J, Nogales J. A portable library of phosphate-depletion based synthetic promoters for customable and automata control of gene expression in bacteria. Microb Biotechnol 2021; 14:2643-2658. [PMID: 33783967 PMCID: PMC8601176 DOI: 10.1111/1751-7915.13808] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/14/2021] [Indexed: 12/14/2022] Open
Abstract
Industrial biotechnology gene expression systems relay on constitutive promoters compromising cellular growth from the start of the bioprocess, or on inducible devices, which require manual addition of cognate inducers. To overcome this shortcoming, we engineered an automata regulatory system based on cell-stress mechanisms. Specifically, we engineered a synthetic and highly portable phosphate-depletion library of promoters inspired by bacterial PHO starvation system (Pliar promoters). Furthermore, we fully characterized 10 synthetic promoters within the background of two well-known bacterial workhorses such as E. coli W and P. putida KT2440. The promoters displayed an interesting host-dependent performance and a wide strength spectrum ranging from 0.4- to 1.3-fold when compared to the wild-type phosphatase alkaline promoter (PphoA). By comparing with available gene expression systems, we proved the suitability of this new library for the automata and effective decoupling of growth from production in P. putida. Growth phase-dependent expression of these promoters could therefore be activated by fine tuning the initial concentration of phosphate in the medium. Finally, the Pliar library was implemented in the SEVA platform in a ready-to-use mode allowing its broad use by the scientific community.
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Affiliation(s)
- Jesús Torres‐Bacete
- Department of Systems BiologyCentro Nacional de Biotecnología (CSIC)Madrid28049Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐Spanish National Research Council (SusPlast‐CSIC)MadridSpain
| | - José Luís García
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐Spanish National Research Council (SusPlast‐CSIC)MadridSpain
- Department of Microbial and Plant BiotechnologyCentro de Investigaciones Biológicas (CIB)Centro Nacional de Biotecnología (CSIC)MadridSpain
| | - Juan Nogales
- Department of Systems BiologyCentro Nacional de Biotecnología (CSIC)Madrid28049Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy‐Spanish National Research Council (SusPlast‐CSIC)MadridSpain
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17
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Zhang J, Pang Q, Wang Q, Qi Q, Wang Q. Modular tuning engineering and versatile applications of genetically encoded biosensors. Crit Rev Biotechnol 2021; 42:1010-1027. [PMID: 34615431 DOI: 10.1080/07388551.2021.1982858] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Genetically encoded biosensors have a diverse range of detectable signals and potential applications in many fields, including metabolism control and high-throughput screening. Their ability to be used in situ with minimal interference to the bioprocess of interest could revolutionize synthetic biology and microbial cell factories. The performance and functions of these biosensors have been extensively studied and have been rapidly improved. We review here current biosensor tuning strategies and attempt to unravel how to obtain ideal biosensor functions through experimental adjustments. Strategies for expanding the biosensor input signals that increases the number of detectable compounds have also been summarized. Finally, different output signals and their practical requirements for biotechnology and biomedical applications and environmental safety concerns have been analyzed. This in-depth review of the responses and regulation mechanisms of genetically encoded biosensors will assist to improve their design and optimization in various application scenarios.
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Affiliation(s)
- Jian Zhang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qingxiao Pang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qi Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qingsheng Qi
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China.,CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Qian Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China.,CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, P. R. China
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18
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Shabestary K, Hernández HP, Miao R, Ljungqvist E, Hallman O, Sporre E, Branco Dos Santos F, Hudson EP. Cycling between growth and production phases increases cyanobacteria bioproduction of lactate. Metab Eng 2021; 68:131-141. [PMID: 34601120 DOI: 10.1016/j.ymben.2021.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/03/2021] [Accepted: 09/25/2021] [Indexed: 01/23/2023]
Abstract
Decoupling growth from product synthesis is a promising strategy to increase carbon partitioning and maximize productivity in cell factories. However, reduction in both substrate uptake rate and metabolic activity in the production phase are an underlying problem for upscaling. Here, we used CRISPR interference to repress growth in lactate-producing Synechocystis sp. PCC 6803. Carbon partitioning to lactate in the production phase exceeded 90%, but CO2 uptake was severely reduced compared to uptake during the growth phase. We characterized strains during the onset of growth arrest using transcriptomics and proteomics. Multiple genes involved in ATP homeostasis were regulated once growth was inhibited, which suggests an alteration of energy charge that may lead to reduced substrate uptake. In order to overcome the reduced metabolic activity and take advantage of increased carbon partitioning, we tested a novel production strategy that involved alternating growth arrest and recovery by periodic addition of an inducer molecule to activate CRISPRi. Using this strategy, we maintained lactate biosynthesis in Synechocystis for 30 days in a constant light turbidostat cultivation. Cumulative lactate titers were also increased by 100% compared to a constant growth-arrest regime, and reached 1 g/L. Further, the cultivation produced lactate for 30 days, compared to 20 days for the non-growth arrest cultivation. Periodic growth arrest could be applicable for other products, and in cyanobacteria, could be linked to internal circadian rhythms that persist in constant light.
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Affiliation(s)
- Kiyan Shabestary
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Hugo Pineda Hernández
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Rui Miao
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Emil Ljungqvist
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Olivia Hallman
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Emil Sporre
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Filipe Branco Dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, the Netherlands
| | - Elton P Hudson
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden.
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19
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You J, Pan X, Yang C, Du Y, Osire T, Yang T, Zhang X, Xu M, Xu G, Rao Z. Microbial production of riboflavin: Biotechnological advances and perspectives. Metab Eng 2021; 68:46-58. [PMID: 34481976 DOI: 10.1016/j.ymben.2021.08.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/19/2021] [Accepted: 08/31/2021] [Indexed: 10/24/2022]
Abstract
Riboflavin is an essential nutrient for humans and animals, and its derivatives flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are cofactors in the cells. Therefore, riboflavin and its derivatives are widely used in the food, pharmaceutical, nutraceutical and cosmetic industries. Advances in biotechnology have led to a complete shift in the commercial production of riboflavin from chemical synthesis to microbial fermentation. In this review, we provide a comprehensive review of biotechnologies that enhance riboflavin production in microorganisms, as well as representative examples. Firstly, the synthesis pathways and metabolic regulatory processes of riboflavin in microorganisms; and the current strategies and methods of metabolic engineering for riboflavin production are systematically summarized and compared. Secondly, the using of systematic metabolic engineering strategies to enhance riboflavin production is discussed, including laboratory evolution, histological analysis and high-throughput screening. Finally, the challenges for efficient microbial production of riboflavin and the strategies to overcome these challenges are prospected.
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Affiliation(s)
- Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Chen Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Yuxuan Du
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Tolbert Osire
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xian Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Meijuan Xu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Guoqiang Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, United States; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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20
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L-valine production in Corynebacterium glutamicum based on systematic metabolic engineering: progress and prospects. Amino Acids 2021; 53:1301-1312. [PMID: 34401958 DOI: 10.1007/s00726-021-03066-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 08/11/2021] [Indexed: 10/20/2022]
Abstract
L-valine is an essential branched-chain amino acid that cannot be synthesized by the human body and has a wide range of applications in food, medicine and feed. Market demand has stimulated people's interest in the industrial production of L-valine. At present, the mutagenized or engineered Corynebacterium glutamicum is an effective microbial cell factory for producing L-valine. Because the biosynthetic pathway and metabolic network of L-valine are intricate and strictly regulated by a variety of key enzymes and genes, highly targeted metabolic engineering can no longer meet the demand for efficient biosynthesis of L-valine. In recent years, the development of omics technology has promoted the upgrading of traditional metabolic engineering to systematic metabolic engineering. This whole-cell-scale transformation strategy has become a productive method for developing L-valine producing strains. This review provides an overview of the biosynthesis and regulation mechanism of L-valine, and summarizes the current metabolic engineering techniques and strategies for constructing L-valine high-producing strains. Finally, the opinion of constructing a cell factory for efficiently biosynthesizing L-valine was proposed.
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21
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Bao SH, Jiang H, Zhu LY, Yao G, Han PG, Wan XK, Wang K, Song TY, Liu CJ, Wang S, Zhang ZY, Zhang DY, Meng E. A dynamic and multilocus metabolic regulation strategy using quorum-sensing-controlled bacterial small RNA. Cell Rep 2021; 36:109413. [PMID: 34289355 DOI: 10.1016/j.celrep.2021.109413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 03/30/2021] [Accepted: 06/25/2021] [Indexed: 12/21/2022] Open
Abstract
Metabolic regulation strategies have been developed to redirect metabolic fluxes to production pathways. However, it is difficult to screen out target genes that, when repressed, improve yield without affecting cell growth. Here, we report a strategy using a quorum-sensing system to control small RNA transcription, allowing cell-density-dependent repression of target genes. This strategy is shown with convenient operation, dynamic repression, and availability for simultaneous regulation of multiple genes. The parameters Ai, Am, and RA (3-oxohexanoyl-homoserine lactone [AHL] concentrations at which half of the maximum repression and the maximum repression were reached and value of the maximum repression when AHL was added manually, respectively) are defined and introduced to characterize repression curves, and the variant LuxRI58N is identified as the most suitable tuning factor for shake flask culture. Moreover, it is shown that dynamic overexpression of the Hfq chaperone is the key to combinatorial repression without disruptions on cell growth. To show a broad applicability, the production titers of pinene, pentalenene, and psilocybin are improved by 365.3%, 79.5%, and 302.9%, respectively, by applying combinatorial dynamic repression.
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Affiliation(s)
- Shao-Heng Bao
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Hui Jiang
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Ling-Yun Zhu
- College of Arts and Sciences, National University of Defense Technology, Changsha, PRC
| | - Ge Yao
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Peng-Gang Han
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Xiu-Kun Wan
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Kang Wang
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Tian-Yu Song
- State Key Laboratory of NBC Protection for Civilian, Beijing, PRC
| | - Chang-Jun Liu
- Hunan Key Laboratory of Economic Crops, Genetic Improvement, and Integrated Utilization, School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PRC
| | - Shan Wang
- Hunan Key Laboratory of Economic Crops, Genetic Improvement, and Integrated Utilization, School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PRC
| | - Zhe-Yang Zhang
- Hunan Key Laboratory of Economic Crops, Genetic Improvement, and Integrated Utilization, School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PRC
| | - Dong-Yi Zhang
- Hunan Key Laboratory of Economic Crops, Genetic Improvement, and Integrated Utilization, School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PRC; College of Arts and Sciences, National University of Defense Technology, Changsha, PRC.
| | - Er Meng
- Hunan Key Laboratory of Economic Crops, Genetic Improvement, and Integrated Utilization, School of Life Sciences, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PRC.
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22
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Xu Y, Wu Y, Lv X, Sun G, Zhang H, Chen T, Du G, Li J, Liu L. Design and construction of novel biocatalyst for bioprocessing: Recent advances and future outlook. BIORESOURCE TECHNOLOGY 2021; 332:125071. [PMID: 33826982 DOI: 10.1016/j.biortech.2021.125071] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Bioprocess, a biocatalysis-based technology, is becoming popular in many research fields and widely applied in industrial manufacturing. However, low bioconversion, low productivity, and high costs during industrial processes are usually the limitation in bioprocess. Therefore, many biocatalyst strategies have been developed to meet these challenges in recent years. In this review, we firstly discuss protein engineering strategies, which are emerged for improving the biocatalysis activity of biocatalysts. Then, we summarize metabolic engineering strategies that are promoting the development of microbial cell factories. Next, we illustrate the necessity of using the combining strategy of protein engineering and metabolic engineering for efficient biocatalysts. Lastly, future perspectives about the development and application of novel biocatalyst strategies are discussed. This review provides theoretical guidance for the development of efficient, sustainable, and economical bioprocesses mediated by novel biocatalysts.
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Affiliation(s)
- Yameng Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Yaokang Wu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Guoyun Sun
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Hongzhi Zhang
- Shandong Runde Biotechnology Co., Ltd., Tai'an 271000, PR China
| | - Taichi Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Guocheng Du
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Jianghua Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, PR China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China.
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23
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Rational engineering strategies for achieving high-yield, high-quality and high-stability of natural product production in actinomycetes. Metab Eng 2021; 67:198-215. [PMID: 34166765 DOI: 10.1016/j.ymben.2021.06.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/30/2021] [Accepted: 06/19/2021] [Indexed: 12/11/2022]
Abstract
Actinomycetes are recognized as excellent producers of microbial natural products, which have a wide range of applications, especially in medicine, agriculture and stockbreeding. The three main indexes of industrialization (titer, purity and stability) must be taken into overall consideration in the manufacturing process of natural products. Over the past decades, synthetic biology techniques have expedited the development of industrially competitive strains with excellent performances. Here, we summarize various rational engineering strategies for upgrading the performance of industrial actinomycetes, which include enhancing the yield of natural products, eliminating the by-products and improving the genetic stability of engineered strains. Furthermore, the current challenges and future perspectives for optimizing the industrial strains more systematically through combinatorial engineering strategies are also discussed.
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24
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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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25
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Ziegler M, Zieringer J, Döring CL, Paul L, Schaal C, Takors R. Engineering of a robust Escherichia coli chassis and exploitation for large-scale production processes. Metab Eng 2021; 67:75-87. [PMID: 34098100 DOI: 10.1016/j.ymben.2021.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 11/28/2022]
Abstract
In large-scale bioprocesses microbes are exposed to heterogeneous substrate availability reducing the overall process performance. A series of deletion strains was constructed from E. coli MG1655 aiming for a robust phenotype in heterogeneous fermentations with transient starvation. Deletion targets were hand-picked based on a list of genes derived from previous large-scale simulation runs. Each gene deletion was conducted on the premise of strict neutrality towards growth parameters in glucose minimal medium. The final strain of the series, named E. coli RM214, was cultivated continuously in an STR-PFR (stirred tank reactor - plug flow reactor) scale-down reactor. The scale-down reactor system simulated repeated passages through a glucose starvation zone. When exposed to nutrient gradients, E. coli RM214 had a significantly lower maintenance coefficient than E. coli MG1655 (Δms = 0.038 gGlucose/gCDW/h, p < 0.05). In an exemplary protein production scenario E. coli RM214 remained significantly more productive than E. coli MG1655 reaching 44% higher eGFP yield after 28 h of STR-PFR cultivation. This study developed E. coli RM214 as a robust chassis strain and demonstrated the feasibility of engineering microbial hosts for large-scale applications.
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Affiliation(s)
- Martin Ziegler
- University of Stuttgart - Institute of Biochemical Engineering, Allmandring 31, 70569, Stuttgart, Germany.
| | - Julia Zieringer
- University of Stuttgart - Institute of Biochemical Engineering, Allmandring 31, 70569, Stuttgart, Germany.
| | - Clarissa-Laura Döring
- University of Stuttgart - Institute of Biochemical Engineering, Allmandring 31, 70569, Stuttgart, Germany.
| | - Liv Paul
- University of Stuttgart - Institute of Biochemical Engineering, Allmandring 31, 70569, Stuttgart, Germany.
| | - Christoph Schaal
- University of Stuttgart - Institute of Biochemical Engineering, Allmandring 31, 70569, Stuttgart, Germany.
| | - Ralf Takors
- University of Stuttgart - Institute of Biochemical Engineering, Allmandring 31, 70569, Stuttgart, Germany.
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26
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Lo TM, Hwang IY, Cho HS, Fedora RE, Chng SH, Choi WJ, Chang MW. Biosynthesis of Commodity Chemicals From Oil Palm Empty Fruit Bunch Lignin. Front Microbiol 2021; 12:663642. [PMID: 33897677 PMCID: PMC8064122 DOI: 10.3389/fmicb.2021.663642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/08/2021] [Indexed: 12/04/2022] Open
Abstract
Lignin is one of the most abundant natural resources that can be exploited for the bioproduction of value-added commodity chemicals. Oil palm empty fruit bunches (OPEFBs), byproducts of palm oil production, are abundant lignocellulosic biomass but largely used for energy and regarded as waste. Pretreatment of OPEFB lignin can yield a mixture of aromatic compounds that can potentially serve as substrates to produce commercially important chemicals. However, separation of the mixture into desired individual substrates is required, which involves expensive steps that undermine the utility of OPEFB lignin. Here, we report successful engineering of microbial hosts that can directly utilize heterogeneous mixtures derived from OPEFB lignin to produce commodity chemicals, adipic acid and levulinic acid. Furthermore, the corresponding bioconversion pathway was placed under a genetic controller to autonomously activate the conversion process as the cells are fed with a depolymerized OPEFB lignin mixture. This study demonstrates a simple, one-pot biosynthesis approach that directly utilizes derivatives of agricultural waste to produce commodity chemicals.
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Affiliation(s)
- Tat-Ming Lo
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - In Young Hwang
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Han-Saem Cho
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Raissa Eka Fedora
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Si Hui Chng
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Won Jae Choi
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, Singapore, Singapore
| | - Matthew Wook Chang
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Synthetic Biology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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27
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Santala S, Santala V, Liu N, Stephanopoulos G. Partitioning metabolism between growth and product synthesis for coordinated production of wax esters in Acinetobacter baylyi ADP1. Biotechnol Bioeng 2021; 118:2283-2292. [PMID: 33666232 DOI: 10.1002/bit.27740] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/17/2021] [Accepted: 02/27/2021] [Indexed: 11/11/2022]
Abstract
Microbial storage compounds, such as wax esters (WE), are potential high-value lipids for the production of specialty chemicals and medicines. Their synthesis, however, is strictly regulated and competes with cell growth, which leads to trade-offs between biomass and product formation. Here, we use metabolic engineering and synergistic substrate cofeeding to partition the metabolism of Acinetobacter baylyi ADP1 into two distinct modules, each dedicated to cell growth and WE biosynthesis, respectively. We first blocked the glyoxylate shunt and upregulated the WE synthesis pathway to direct the acetate substrate exclusively for WE synthesis, then we controlled the supply of gluconate so it could be used exclusively for cell growth and maintenance. We show that the two modules are functionally independent from each other, allowing efficient lipid accumulation while maintaining active cell growth. Our strategy resulted in 7.2- and 4.2-fold improvements in WE content and productivity, respectively, and the product titer was enhanced by 8.3-fold over the wild type strain. Notably, during a 24-h cultivation, a yield of 18% C-WE/C-total-substrates was achieved, being the highest reported for WE biosynthesis. This study provides a simple, yet powerful, means of controlling cellular operations and overcoming some of the fundamental challenges in microbial storage lipid production.
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Affiliation(s)
- Suvi Santala
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Ville Santala
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.,Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Nian Liu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Gregory Stephanopoulos
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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28
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Riley LA, Guss AM. Approaches to genetic tool development for rapid domestication of non-model microorganisms. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:30. [PMID: 33494801 PMCID: PMC7830746 DOI: 10.1186/s13068-020-01872-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/30/2020] [Indexed: 05/04/2023]
Abstract
Non-model microorganisms often possess complex phenotypes that could be important for the future of biofuel and chemical production. They have received significant interest the last several years, but advancement is still slow due to the lack of a robust genetic toolbox in most organisms. Typically, "domestication" of a new non-model microorganism has been done on an ad hoc basis, and historically, it can take years to develop transformation and basic genetic tools. Here, we review the barriers and solutions to rapid development of genetic transformation tools in new hosts, with a major focus on Restriction-Modification systems, which are a well-known and significant barrier to efficient transformation. We further explore the tools and approaches used for efficient gene deletion, DNA insertion, and heterologous gene expression. Finally, more advanced and high-throughput tools are now being developed in diverse non-model microbes, paving the way for rapid and multiplexed genome engineering for biotechnology.
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Affiliation(s)
- Lauren A Riley
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA
| | - Adam M Guss
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
- Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA.
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29
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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: 74] [Impact Index Per Article: 24.7] [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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30
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Ferreira SS, Antunes MS. Re-engineering Plant Phenylpropanoid Metabolism With the Aid of Synthetic Biosensors. FRONTIERS IN PLANT SCIENCE 2021; 12:701385. [PMID: 34603348 PMCID: PMC8481569 DOI: 10.3389/fpls.2021.701385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/23/2021] [Indexed: 05/03/2023]
Abstract
Phenylpropanoids comprise a large class of specialized plant metabolites with many important applications, including pharmaceuticals, food nutrients, colorants, fragrances, and biofuels. Therefore, much effort has been devoted to manipulating their biosynthesis to produce high yields in a more controlled manner in microbial and plant systems. However, current strategies are prone to significant adverse effects due to pathway complexity, metabolic burden, and metabolite bioactivity, which still hinder the development of tailor-made phenylpropanoid biofactories. This gap could be addressed by the use of biosensors, which are molecular devices capable of sensing specific metabolites and triggering a desired response, as a way to sense the pathway's metabolic status and dynamically regulate its flux based on specific signals. Here, we provide a brief overview of current research on synthetic biology and metabolic engineering approaches to control phenylpropanoid synthesis and phenylpropanoid-related biosensors, advocating for the use of biosensors and genetic circuits as a step forward in plant synthetic biology to develop autonomously-controlled phenylpropanoid-producing plant biofactories.
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31
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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: 10] [Impact Index Per Article: 2.5] [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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32
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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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33
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Foo JL, Rasouliha BH, Susanto AV, Leong SSJ, Chang MW. Engineering an Alcohol-Forming Fatty Acyl-CoA Reductase for Aldehyde and Hydrocarbon Biosynthesis in Saccharomyces cerevisiae. Front Bioeng Biotechnol 2020; 8:585935. [PMID: 33123518 PMCID: PMC7573125 DOI: 10.3389/fbioe.2020.585935] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/08/2020] [Indexed: 11/19/2022] Open
Abstract
Aldehydes are a class of highly versatile chemicals that can undergo a wide range of chemical reactions and are in high demand as starting materials for chemical manufacturing. Biologically, fatty aldehydes can be produced from fatty acyl-CoA by the action of fatty acyl-CoA reductases. The aldehydes produced can be further converted enzymatically to other valuable derivatives. Thus, metabolic engineering of microorganisms for biosynthesizing aldehydes and their derivatives could provide an economical and sustainable platform for key aldehyde precursor production and subsequent conversion to various value-added chemicals. Saccharomyces cerevisiae is an excellent host for this purpose because it is a robust organism that has been used extensively for industrial biochemical production. However, fatty acyl-CoA-dependent aldehyde-forming enzymes expressed in S. cerevisiae thus far have extremely low activities, hence limiting direct utilization of fatty acyl-CoA as substrate for aldehyde biosynthesis. Toward overcoming this challenge, we successfully engineered an alcohol-forming fatty acyl-CoA reductase for aldehyde production through rational design. We further improved aldehyde production through strain engineering by deleting competing pathways and increasing substrate availability. Subsequently, we demonstrated alkane and alkene production as one of the many possible applications of the aldehyde-producing strain. Overall, by protein engineering of a fatty acyl-CoA reductase to alter its activity and metabolic engineering of S. cerevisiae, we generated strains with the highest reported cytosolic aliphatic aldehyde and alkane/alkene production to date in S. cerevisiae from fatty acyl-CoA.
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Affiliation(s)
- Jee Loon Foo
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
| | - Bahareh Haji Rasouliha
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
| | - Adelia Vicanatalita Susanto
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
| | - Susanna Su Jan Leong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore.,Singapore Institute of Technology, Singapore, Singapore
| | - Matthew Wook Chang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
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34
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Banerjee D, Eng T, Lau AK, Sasaki Y, Wang B, Chen Y, Prahl JP, Singan VR, Herbert RA, Liu Y, Tanjore D, Petzold CJ, Keasling JD, Mukhopadhyay A. Genome-scale metabolic rewiring improves titers rates and yields of the non-native product indigoidine at scale. Nat Commun 2020; 11:5385. [PMID: 33097726 PMCID: PMC7584609 DOI: 10.1038/s41467-020-19171-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/30/2020] [Indexed: 01/06/2023] Open
Abstract
High titer, rate, yield (TRY), and scalability are challenging metrics to achieve due to trade-offs between carbon use for growth and production. To achieve these metrics, we take the minimal cut set (MCS) approach that predicts metabolic reactions for elimination to couple metabolite production strongly with growth. We compute MCS solution-sets for a non-native product indigoidine, a sustainable pigment, in Pseudomonas putida KT2440, an emerging industrial microbe. From the 63 solution-sets, our omics guided process identifies one experimentally feasible solution requiring 14 simultaneous reaction interventions. We implement a total of 14 genes knockdowns using multiplex-CRISPRi. MCS-based solution shifts production from stationary to exponential phase. We achieve 25.6 g/L, 0.22 g/l/h, and ~50% maximum theoretical yield (0.33 g indigoidine/g glucose). These phenotypes are maintained from batch to fed-batch mode, and across scales (100-ml shake flasks, 250-ml ambr®, and 2-L bioreactors).
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Affiliation(s)
- Deepanwita Banerjee
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Thomas Eng
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andrew K Lau
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yusuke Sasaki
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Brenda Wang
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yan Chen
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jan-Philip Prahl
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Advanced Biofuel and Bioproduct Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
| | - Vasanth R Singan
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Robin A Herbert
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yuzhong Liu
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Deepti Tanjore
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Advanced Biofuel and Bioproduct Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
| | - Christopher J Petzold
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jay D Keasling
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- QB3 Institute, University of California-Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA, 94608, USA
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University Denmark, 2970, Horsholm, Denmark
- Synthetic Biochemistry Center, Institute for Synthetic Biology, Shenzhen Institutes for Advanced Technologies, Shenzhen, China
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA.
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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35
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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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36
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Titrating bacterial growth and chemical biosynthesis for efficient N-acetylglucosamine and N-acetylneuraminic acid bioproduction. Nat Commun 2020; 11:5078. [PMID: 33033266 PMCID: PMC7544899 DOI: 10.1038/s41467-020-18960-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 09/21/2020] [Indexed: 12/27/2022] Open
Abstract
Metabolic engineering facilitates chemical biosynthesis by rewiring cellular resources to produce target compounds. However, an imbalance between cell growth and bioproduction often reduces production efficiency. Genetic code expansion (GCE)-based orthogonal translation systems incorporating non-canonical amino acids (ncAAs) into proteins by reassigning non-canonical codons to ncAAs qualify for balancing cellular metabolism. Here, GCE-based cell growth and biosynthesis balance engineering (GCE-CGBBE) is developed, which is based on titrating expression of cell growth and metabolic flux determinant genes by constructing ncAA-dependent expression patterns. We demonstrate GCE-CGBBE in genome-recoded Escherichia coli Δ321AM by precisely balancing glycolysis and N-acetylglucosamine production, resulting in a 4.54-fold increase in titer. GCE-CGBBE is further expanded to non-genome-recoded Bacillus subtilis to balance growth and N-acetylneuraminic acid bioproduction by titrating essential gene expression, yielding a 2.34-fold increase in titer. Moreover, the development of ncAA-dependent essential gene expression regulation shows efficient biocontainment of engineered B. subtilis to avoid unintended proliferation in nature. An imbalance between cell growth and bioproduction of engineered microbes often reduces production efficiency. Here, the authors report genetic code expansion-based cell growth and biosynthesis balance engineering to achieve high levels production of N-acetylglucosamine in E. coli and N-acetylneuraminic acid in B. subtilis.
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37
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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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38
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Yeoh JW, Jayaraman SS, Tan SGD, Jayaraman P, Holowko MB, Zhang J, Kang CW, Leo HL, Poh CL. A model-driven approach towards rational microbial bioprocess optimization. Biotechnol Bioeng 2020; 118:305-318. [PMID: 32946111 DOI: 10.1002/bit.27571] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/06/2020] [Accepted: 09/16/2020] [Indexed: 12/31/2022]
Abstract
Due to sustainability concerns, bio-based production capitalizing on microbes as cell factories is in demand to synthesize valuable products. Nevertheless, the nonhomogenous variations of the extracellular environment in bioprocesses often challenge the biomass growth and the bioproduction yield. To enable a more rational bioprocess optimization, we have established a model-driven approach that systematically integrates experiments with modeling, executed from flask to bioreactor scale, and using ferulic acid to vanillin bioconversion as a case study. The impacts of mass transfer and aeration on the biomass growth and bioproduction performances were examined using minimal small-scale experiments. An integrated model coupling the cell factory kinetics with the three-dimensional computational hydrodynamics of bioreactor was developed to better capture the spatiotemporal distributions of bioproduction. Full-factorial predictions were then performed to identify the desired operating conditions. A bioconversion yield of 94% was achieved, which is one of the highest for recombinant Escherichia coli using ferulic acid as the precursor.
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Affiliation(s)
- Jing Wui Yeoh
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Life Sciences Institute, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, Singapore
| | - Sudhaghar S/O Jayaraman
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Life Sciences Institute, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, Singapore
| | - Sean Guo-Dong Tan
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore
| | - Premkumar Jayaraman
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Life Sciences Institute, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, Singapore
| | - Maciej B Holowko
- Life Sciences Institute, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, Singapore
| | - Jingyun Zhang
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Life Sciences Institute, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, Singapore
| | - Chang-Wei Kang
- Department of Fluid Dynamic, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore
| | - Chueh Loo Poh
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.,Life Sciences Institute, NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, Singapore
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39
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Liu Y, Su A, Li J, Ledesma-Amaro R, Xu P, Du G, Liu L. Towards next-generation model microorganism chassis for biomanufacturing. Appl Microbiol Biotechnol 2020; 104:9095-9108. [DOI: 10.1007/s00253-020-10902-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 11/29/2022]
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40
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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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41
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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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42
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Landberg J, Wright NR, Wulff T, Herrgård MJ, Nielsen AT. CRISPR interference of nucleotide biosynthesis improves production of a single-domain antibody in Escherichia coli. Biotechnol Bioeng 2020; 117:3835-3848. [PMID: 32808670 PMCID: PMC7818426 DOI: 10.1002/bit.27536] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/23/2022]
Abstract
Growth decoupling can be used to optimize the production of biochemicals and proteins in cell factories. Inhibition of excess biomass formation allows for carbon to be utilized efficiently for product formation instead of growth, resulting in increased product yields and titers. Here, we used CRISPR interference to increase the production of a single‐domain antibody (sdAb) by inhibiting growth during production. First, we screened 21 sgRNA targets in the purine and pyrimidine biosynthesis pathways and found that the repression of 11 pathway genes led to the increased green fluorescent protein production and decreased growth. The sgRNA targets pyrF, pyrG, and cmk were selected and further used to improve the production of two versions of an expression‐optimized sdAb. Proteomics analysis of the sdAb‐producing pyrF, pyrG, and cmk growth decoupling strains showed significantly decreased RpoS levels and an increase of ribosome‐associated proteins, indicating that the growth decoupling strains do not enter stationary phase and maintain their capacity for protein synthesis upon growth inhibition. Finally, sdAb production was scaled up to shake‐flask fermentation where the product yield was improved 2.6‐fold compared to the control strain with no sgRNA target sequence. An sdAb content of 14.6% was reached in the best‐performing pyrG growth decoupling strain.
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Affiliation(s)
- Jenny Landberg
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Naia Risager Wright
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Tune Wulff
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Markus J Herrgård
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
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43
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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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44
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Li S, Jendresen CB, Landberg J, Pedersen LE, Sonnenschein N, Jensen SI, Nielsen AT. Genome-Wide CRISPRi-Based Identification of Targets for Decoupling Growth from Production. ACS Synth Biol 2020; 9:1030-1040. [PMID: 32268068 DOI: 10.1021/acssynbio.9b00143] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Growth decoupling can be used to optimize microbial production of biobased compounds by inhibiting excess biomass formation and redirect carbon flux from growth to product formation. However, identifying suitable genetic targets through rational design is challenging. Here, we conduct a genome-wide CRISPRi screen to discover growth switches suitable for decoupling growth and production. Using an sgRNA library covering 12 238 loci in the Escherichia coli genome, we screen for targets that inhibit growth while allowing for continued protein production. In total, we identify 1332 sgRNAs that simultaneously decrease growth and maintain or increase accumulation of GFP. The top target sibB/ibsB shows more than 5-fold increase in GFP accumulation and 45% decrease in biomass formation. Overall, our genome-wide CRISPRi screen provides key targets for growth decoupling, and the approach can be applied to improve biobased production in other microorganisms.
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Affiliation(s)
- Songyuan Li
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
| | - Christian Bille Jendresen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
- CysBio ApS, Agern Allé 1, 2970 Hørsholm, Denmark
| | - Jenny Landberg
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
| | - Lasse Ebdrup Pedersen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
| | - Nikolaus Sonnenschein
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
| | - Sheila Ingemann Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kongens Lyngby, Denmark
- CysBio ApS, Agern Allé 1, 2970 Hørsholm, Denmark
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45
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Berepiki A, Kent R, Machado LFM, Dixon N. Development of High-Performance Whole Cell Biosensors Aided by Statistical Modeling. ACS Synth Biol 2020; 9:576-589. [PMID: 32023410 PMCID: PMC7146887 DOI: 10.1021/acssynbio.9b00448] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Whole cell biosensors are genetic systems that link the presence of a chemical, or other stimulus, to a user-defined gene expression output for applications in sensing and control. However, the gene expression level of biosensor regulatory components required for optimal performance is nonintuitive, and classical iterative approaches do not efficiently explore multidimensional experimental space. To overcome these challenges, we used a design of experiments (DoE) methodology to efficiently map gene expression levels and provide biosensors with enhanced performance. This methodology was applied to two biosensors that respond to catabolic breakdown products of lignin biomass, protocatechuic acid and ferulic acid. Utilizing DoE we systematically modified biosensor dose-response behavior by increasing the maximum signal output (up to 30-fold increase), improving dynamic range (>500-fold), expanding the sensing range (∼4-orders of magnitude), increasing sensitivity (by >1500-fold), and modulated the slope of the curve to afford biosensors designs with both digital and analogue dose-response behavior. This DoE method shows promise for the optimization of regulatory systems and metabolic pathways constructed from novel, poorly characterized parts.
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Affiliation(s)
- Adokiye Berepiki
- †Manchester
Institute of Biotechnology (MIB), ‡SYNBIOCHEM, Department of Chemistry, University of Manchester, Manchester M1 7DN, U.K.
| | - Ross Kent
- †Manchester
Institute of Biotechnology (MIB), ‡SYNBIOCHEM, Department of Chemistry, University of Manchester, Manchester M1 7DN, U.K.
| | - Leopoldo F. M. Machado
- †Manchester
Institute of Biotechnology (MIB), ‡SYNBIOCHEM, Department of Chemistry, University of Manchester, Manchester M1 7DN, U.K.
| | - Neil Dixon
- †Manchester
Institute of Biotechnology (MIB), ‡SYNBIOCHEM, Department of Chemistry, University of Manchester, Manchester M1 7DN, U.K.,E-mail:
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46
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Development of an autonomous and bifunctional quorum-sensing circuit for metabolic flux control in engineered Escherichia coli. Proc Natl Acad Sci U S A 2019; 116:25562-25568. [PMID: 31796590 DOI: 10.1073/pnas.1911144116] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Metabolic engineering seeks to reprogram microbial cells to efficiently and sustainably produce value-added compounds. Since chemical production can be at odds with the cell's natural objectives, strategies have been developed to balance conflicting goals. For example, dynamic regulation modulates gene expression to favor biomass and metabolite accumulation at low cell densities before diverting key metabolic fluxes toward product formation. To trigger changes in gene expression in a pathway-independent manner without the need for exogenous inducers, researchers have coupled gene expression to quorum-sensing (QS) circuits, which regulate transcription based on cell density. While effective, studies thus far have been limited to one control point. More challenging pathways may require layered dynamic regulation strategies, motivating the development of a generalizable tool for regulating multiple sets of genes. We have developed a QS-based regulation tool that combines components of the lux and esa QS systems to simultaneously and dynamically up- and down-regulate expression of 2 sets of genes. Characterization of the circuit revealed that varying the expression level of 2 QS components leads to predictable changes in switching dynamics and that using components from 2 QS systems allows for independent tuning capability. We applied the regulation tool to successfully address challenges in both the naringenin and salicylic acid synthesis pathways. Through these case studies, we confirmed the benefit of having multiple control points, predictable tuning capabilities, and independently tunable regulation modules.
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47
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Kent R, Dixon N. Contemporary Tools for Regulating Gene Expression in Bacteria. Trends Biotechnol 2019; 38:316-333. [PMID: 31679824 DOI: 10.1016/j.tibtech.2019.09.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/14/2022]
Abstract
Insights from novel mechanistic paradigms in gene expression control have led to the development of new gene expression systems for bioproduction, control, and sensing applications. Coupled with a greater understanding of synthetic burden and modern creative biodesign approaches, contemporary bacterial gene expression tools and systems are emerging that permit fine-tuning of expression, enabling greater predictability and maximisation of specific productivity, while minimising deleterious effects upon cell viability. These advances have been achieved by using a plethora of regulatory tools, operating at all levels of the so-called 'central dogma' of molecular biology. In this review, we discuss these gene regulation tools in the context of their design, prototyping, integration into expression systems, and biotechnological application.
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Affiliation(s)
- Ross Kent
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester, UK
| | - Neil Dixon
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester, UK.
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48
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Alvarez-Gonzalez G, Dixon N. Genetically encoded biosensors for lignocellulose valorization. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:246. [PMID: 31636705 PMCID: PMC6792243 DOI: 10.1186/s13068-019-1585-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/05/2019] [Indexed: 05/07/2023]
Abstract
Modern society is hugely dependent on finite oil reserves for the supply of fuels and chemicals. Moving our dependence away from these unsustainable oil-based feedstocks to renewable ones is, therefore, a critical factor towards the development of a low carbon bioeconomy. Lignin derived from biomass feedstocks offers great potential as a renewable source of aromatic compounds if methods for its effective valorization can be developed. Synthetic biology and metabolic engineering offer the potential to synergistically enable the development of cell factories with novel biosynthetic routes to valuable chemicals from these sustainable sources. Pathway design and optimization is, however, a major bottleneck due to the lack of high-throughput methods capable of screening large libraries of genetic variants and the metabolic burden associated with bioproduction. Genetically encoded biosensors can provide a solution by transducing the target metabolite concentration into detectable signals to provide high-throughput phenotypic read-outs and allow dynamic pathway regulation. The development and application of biosensors in the discovery and engineering of efficient biocatalytic processes for the degradation, conversion, and valorization of lignin are paving the way towards a sustainable and economically viable biorefinery.
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Affiliation(s)
| | - Neil Dixon
- Manchester Institute of Biotechnology (MIB), The University of Manchester, Manchester, UK
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49
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Kim SG, Noh MH, Lim HG, Jang S, Jang S, Koffas MAG, Jung GY. Molecular parts and genetic circuits for metabolic engineering of microorganisms. FEMS Microbiol Lett 2019; 365:5059574. [PMID: 30052915 DOI: 10.1093/femsle/fny187] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 07/24/2018] [Indexed: 12/17/2022] Open
Abstract
Microbial conversion of biomass into value-added biochemicals is a highly sustainable process compared to petroleum-based production. In this regard, microorganisms have been engineered via simple overexpression or deletion of metabolic genes to facilitate the production. However, the producer microorganisms require complex regulatory circuits to maximize productivity and performance. To address this issue, diverse genetic circuits have been developed that allow cells to minimize their metabolic burden, overcome metabolic imbalances and respond to a dynamically changing environment. In this review, we briefly explain the basic strategy for constructing genetic circuits by assembling molecular parts such as input, operation and output modules. Next, we describe recent applications of the circuits in the metabolic engineering of microorganisms to improve biochemical production. Beyond those achievements, genetic circuits will facilitate more innovative approaches to future strain development through mining and engineering new genetic elements and improving the complexity of genetic circuit design.
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Affiliation(s)
- Seong Gyeong Kim
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea
| | - Myung Hyun Noh
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea
| | - Hyun Gyu Lim
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea
| | - Sungho Jang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea
| | - Sungyeon Jang
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea
| | - Mattheos A G Koffas
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy 12180, USA
| | - Gyoo Yeol Jung
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea
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50
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Mixed carbon substrates: a necessary nuisance or a missed opportunity? Curr Opin Biotechnol 2019; 62:15-21. [PMID: 31513988 DOI: 10.1016/j.copbio.2019.07.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 06/24/2019] [Accepted: 07/03/2019] [Indexed: 11/20/2022]
Abstract
Although fermentation with single carbon sources is the preferred mode of operation in current industrial biotechnology, the use of multiple substrates has been continuously investigated throughout the years. Generally, microbial metabolism varies significantly when cells are presented with mixed carbon substrates compared to a single carbon-energy source, as different nutrients interact in complex ways within the metabolic network. By exploiting these distinct modes of interaction, researchers have identified unique opportunities to optimize metabolism using mixed carbon sources. Here we review situations where process yield and productivity are markedly improved through the judicious introduction of substrate mixtures. Our goal is to illustrate that with proper design of the choice of substrates and the way they are introduced to cultures, metabolic optimization with mixed substrates can be a unique strategy that complements genetic engineering techniques to enhance cell performance beyond what is accomplished in single substrate fermentations.
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