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Yin L, Zhou Y, Ding N, Fang Y. Recent Advances in Metabolic Engineering for the Biosynthesis of Phosphoenol Pyruvate-Oxaloacetate-Pyruvate-Derived Amino Acids. Molecules 2024; 29:2893. [PMID: 38930958 PMCID: PMC11206799 DOI: 10.3390/molecules29122893] [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: 04/27/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
The phosphoenol pyruvate-oxaloacetate-pyruvate-derived amino acids (POP-AAs) comprise native intermediates in cellular metabolism, within which the phosphoenol pyruvate-oxaloacetate-pyruvate (POP) node is the switch point among the major metabolic pathways existing in most living organisms. POP-AAs have widespread applications in the nutrition, food, and pharmaceutical industries. These amino acids have been predominantly produced in Escherichia coli and Corynebacterium glutamicum through microbial fermentation. With the rapid increase in market requirements, along with the global food shortage situation, the industrial production capacity of these two bacteria has encountered two bottlenecks: low product conversion efficiency and high cost of raw materials. Aiming to push forward the update and upgrade of engineered strains with higher yield and productivity, this paper presents a comprehensive summarization of the fundamental strategy of metabolic engineering techniques around phosphoenol pyruvate-oxaloacetate-pyruvate node for POP-AA production, including L-tryptophan, L-tyrosine, L-phenylalanine, L-valine, L-lysine, L-threonine, and L-isoleucine. Novel heterologous routes and regulation methods regarding the carbon flux redistribution in the POP node and the formation of amino acids should be taken into consideration to improve POP-AA production to approach maximum theoretical values. Furthermore, an outlook for future strategies of low-cost feedstock and energy utilization for developing amino acid overproducers is proposed.
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Affiliation(s)
- Lianghong Yin
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; (L.Y.); (Y.Z.)
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A&F University, Hangzhou 311300, China
| | - Yanan Zhou
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; (L.Y.); (Y.Z.)
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A&F University, Hangzhou 311300, China
| | - Nana Ding
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; (L.Y.); (Y.Z.)
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A&F University, Hangzhou 311300, China
| | - Yu Fang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; (L.Y.); (Y.Z.)
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A&F University, Hangzhou 311300, China
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2
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Hao Y, Pan X, You J, Li G, Xu M, Rao Z. Microbial production of branched chain amino acids: Advances and perspectives. BIORESOURCE TECHNOLOGY 2024; 397:130502. [PMID: 38417463 DOI: 10.1016/j.biortech.2024.130502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 02/23/2024] [Accepted: 02/25/2024] [Indexed: 03/01/2024]
Abstract
Branched-chain amino acids (BCAAs) such as L-valine, L-leucine, and L-isoleucine are widely used in food and feed. To comply with sustainable development goals, commercial production of BCAAs has been completely replaced with microbial fermentation. However, the efficient production of BCAAs by microorganisms remains a serious challenge due to their staggered metabolic networks and cell growth. To overcome these difficulties, systemic metabolic engineering has emerged as an effective and feasible strategy for the biosynthesis of BCAA. This review firstly summarizes the research advances in the microbial synthesis of BCAAs and representative engineering strategies. Second, systematic methods, such as high-throughput screening, adaptive laboratory evolution, and omics analysis, can be used to analyses the synthesis of BCAAs at the whole-cell level and further improve the titer of target chemicals. Finally, new tools and engineering strategies that may increase the production output and development direction of the microbial production of BCAAs are discussed.
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Affiliation(s)
- Yanan Hao
- 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
| | - 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
| | - Guomin Li
- 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
| | - 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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Kim K, Choe D, Cho S, Palsson B, Cho BK. Reduction-to-synthesis: the dominant approach to genome-scale synthetic biology. Trends Biotechnol 2024:S0167-7799(24)00037-4. [PMID: 38423803 DOI: 10.1016/j.tibtech.2024.02.008] [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: 12/14/2023] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 03/02/2024]
Abstract
Advances in systems and synthetic biology have propelled the construction of reduced bacterial genomes. Genome reduction was initially focused on exploring properties of minimal genomes, but more recently it has been deployed as an engineering strategy to enhance strain performance. This review provides the latest updates on reduced genomes, focusing on dual-track approaches of top-down reduction and bottom-up synthesis for their construction. Using cases from studies that are based on established industrial workhorse strains, we discuss the construction of a series of synthetic phenotypes that are candidates for biotechnological applications. Finally, we address the possible uses of reduced genomes for biotechnological applications and the needed future research directions that may ultimately lead to the total synthesis of rationally designed genomes.
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Affiliation(s)
- Kangsan Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Donghui Choe
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Suhyung Cho
- KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Bernhard Palsson
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Kongens, Lyngby, Denmark
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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4
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Amendola CR, Cordell WT, Kneucker CM, Szostkiewicz CJ, Ingraham MA, Monninger M, Wilton R, Pfleger BF, Salvachúa D, Johnson CW, Beckham GT. Comparison of wild-type KT2440 and genome-reduced EM42 Pseudomonas putida strains for muconate production from aromatic compounds and glucose. Metab Eng 2024; 81:88-99. [PMID: 38000549 DOI: 10.1016/j.ymben.2023.11.004] [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: 08/02/2023] [Revised: 11/12/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023]
Abstract
Pseudomonas putida KT2440 is a robust, aromatic catabolic bacterium that has been widely engineered to convert bio-based and waste-based feedstocks to target products. Towards industrial domestication of P. putida KT2440, rational genome reduction has been previously conducted, resulting in P. putida strain EM42, which exhibited characteristics that could be advantageous for production strains. Here, we compared P. putida KT2440- and EM42-derived strains for cis,cis-muconic acid production from an aromatic compound, p-coumarate, and in separate strains, from glucose. To our surprise, the EM42-derived strains did not outperform the KT2440-derived strains in muconate production from either substrate. In bioreactor cultivations, KT2440- and EM42-derived strains produced muconate from p-coumarate at titers of 45 g/L and 37 g/L, respectively, and from glucose at 20 g/L and 13 g/L, respectively. To provide additional insights about the differences in the parent strains, we analyzed growth profiles of KT2440 and EM42 on aromatic compounds as the sole carbon and energy sources. In general, the EM42 strain exhibited reduced growth rates but shorter growth lags than KT2440. We also observed that EM42-derived strains resulted in higher growth rates on glucose compared to KT2440-derived strains, but only at the lowest glucose concentrations tested. Transcriptomics revealed that genome reduction in EM42 had global effects on transcript levels and showed that the EM42-derived strains that produce muconate from glucose exhibit reduced modulation of gene expression in response to changes in glucose concentrations. Overall, our results highlight that additional studies are warranted to understand the effects of genome reduction on microbial metabolism and physiology, especially when intended for use in production strains.
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Affiliation(s)
- Caroline R Amendola
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA
| | - William T Cordell
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Colin M Kneucker
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA
| | - Caralyn J Szostkiewicz
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA
| | - Morgan A Ingraham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA
| | - Michela Monninger
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA
| | - Rosemarie Wilton
- Agile BioFoundry, Emeryville, CA, 94608, USA; Biosciences Division Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Davinia Salvachúa
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA
| | - Christopher W Johnson
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA.
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Agile BioFoundry, Emeryville, CA, 94608, USA.
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5
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Wang Y, Bai Y, Zeng Q, Jiang Z, Liu Y, Wang X, Liu X, Liu C, Min W. Recent advances in the metabolic engineering and physiological opportunities for microbial synthesis of L-aspartic acid family amino acids: A review. Int J Biol Macromol 2023; 253:126916. [PMID: 37716660 DOI: 10.1016/j.ijbiomac.2023.126916] [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: 07/24/2023] [Revised: 09/10/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
L-aspartic acid, L-threonine, L-isoleucine, l-lysine, and L-methionine constitute the l-aspartate amino acids (AFAAs). Except for L-aspartic acid, these are essential amino acids that cannot be synthesized by humans or animals themselves. E. coli and C. glutamicum are the main model organisms for AFAA production. It is necessary to reconstitute microbial cell factories and the physiological state of industrial fermentation cells for in-depth research into strains with higher AFAA production levels and optimal growth states. Considering that the anabolic pathways of the AFAAs and engineering modifications have rarely been reviewed in the latest progress, this work reviews the central metabolic pathways of two strains and strategies for the metabolic engineering of AFAA synthetic pathways. The challenges posed by microbial physiology in AFAA production and possible strategies to address them, as well as future research directions for constructing strains with high AFAA production levels, are discussed in this review article.
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Affiliation(s)
- Yusheng Wang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Yunlong Bai
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Qi Zeng
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Zeyuan Jiang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Yuzhe Liu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Xiyan Wang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Xiaoting Liu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Chunlei Liu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China.
| | - Weihong Min
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China.
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Hanke P, Parrello B, Vasieva O, Akins C, Chlenski P, Babnigg G, Henry C, Foflonker F, Brettin T, Antonopoulos D, Stevens R, Fonstein M. Engineering of increased L-Threonine production in bacteria by combinatorial cloning and machine learning. Metab Eng Commun 2023; 17:e00225. [PMID: 37435441 PMCID: PMC10331477 DOI: 10.1016/j.mec.2023.e00225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 07/13/2023] Open
Abstract
The goal of this study is to develop a general strategy for bacterial engineering using an integrated synthetic biology and machine learning (ML) approach. This strategy was developed in the context of increasing L-threonine production in Escherichia coli ATCC 21277. A set of 16 genes was initially selected based on metabolic pathway relevance to threonine biosynthesis and used for combinatorial cloning to construct a set of 385 strains to generate training data (i.e., a range of L-threonine titers linked to each of the specific gene combinations). Hybrid (regression/classification) deep learning (DL) models were developed and used to predict additional gene combinations in subsequent rounds of combinatorial cloning for increased L-threonine production based on the training data. As a result, E. coli strains built after just three rounds of iterative combinatorial cloning and model prediction generated higher L-threonine titers (from 2.7 g/L to 8.4 g/L) than those of patented L-threonine strains being used as controls (4-5 g/L). Interesting combinations of genes in L-threonine production included deletions of the tdh, metL, dapA, and dhaM genes as well as overexpression of the pntAB, ppc, and aspC genes. Mechanistic analysis of the metabolic system constraints for the best performing constructs offers ways to improve the models by adjusting weights for specific gene combinations. Graph theory analysis of pairwise gene modifications and corresponding levels of L-threonine production also suggests additional rules that can be incorporated into future ML models.
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Affiliation(s)
- Paul Hanke
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
| | - Bruce Parrello
- University of Chicago, 5801 S. Ellis Ave, Chicago, IL, 60637, USA
| | - Olga Vasieva
- BSMI, 1818 Skokie Blvd., #201, Northbrook, IL, 60062, USA
| | - Chase Akins
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
| | - Philippe Chlenski
- Department of Computer Science, Columbia University, New York, NY, 10027, USA
| | - Gyorgy Babnigg
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
| | - Chris Henry
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
| | - Fatima Foflonker
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
| | - Thomas Brettin
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
| | | | - Rick Stevens
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
- University of Chicago, 5801 S. Ellis Ave, Chicago, IL, 60637, USA
| | - Michael Fonstein
- Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL, 60439, USA
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7
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Wagner N, Wen L, Frazão CJR, Walther T. Next-generation feedstocks methanol and ethylene glycol and their potential in industrial biotechnology. Biotechnol Adv 2023; 69:108276. [PMID: 37918546 DOI: 10.1016/j.biotechadv.2023.108276] [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: 09/04/2023] [Revised: 10/13/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023]
Abstract
Microbial fermentation processes are expected to play an important role in reducing dependence on fossil-based raw materials for the production of everyday chemicals. In order to meet the growing demand for biotechnological products in the future, alternative carbon sources that do not compete with human nutrition must be exploited. The chemical conversion of the industrially emitted greenhouse gas CO2 into microbially utilizable platform chemicals such as methanol represents a sustainable strategy for the utilization of an abundant carbon source and has attracted enormous scientific interest in recent years. A relatively new approach is the microbial synthesis of products from the C2-compound ethylene glycol, which can also be synthesized from CO2 and non-edible biomass and, in addition, can be recovered from plastic waste. Here we summarize the main chemical routes for the synthesis of methanol and ethylene glycol from sustainable resources and give an overview of recent metabolic engineering work for establishing natural and synthetic microbial assimilation pathways. The different metabolic routes for C1 and C2 alcohol-dependent bioconversions were compared in terms of their theoretical maximum yields and their oxygen requirements for a wide range of value-added products. Assessment of the process engineering challenges for methanol and ethylene glycol-based fermentations underscores the theoretical advantages of new synthetic metabolic routes and advocates greater consideration of ethylene glycol, a C2 substrate that has received comparatively little attention to date.
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Affiliation(s)
- Nils Wagner
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany
| | - Linxuan Wen
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany
| | - Cláudio J R Frazão
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany
| | - Thomas Walther
- TU Dresden, Institute of Natural Materials Technology, Bergstraße 120, 01062 Dresden, Germany.
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Aida H, Ying BW. Efforts to Minimise the Bacterial Genome as a Free-Living Growing System. BIOLOGY 2023; 12:1170. [PMID: 37759570 PMCID: PMC10525146 DOI: 10.3390/biology12091170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
Exploring the minimal genetic requirements for cells to maintain free living is an exciting topic in biology. Multiple approaches are employed to address the question of the minimal genome. In addition to constructing the synthetic genome in the test tube, reducing the size of the wild-type genome is a practical approach for obtaining the essential genomic sequence for living cells. The well-studied Escherichia coli has been used as a model organism for genome reduction owing to its fast growth and easy manipulation. Extensive studies have reported how to reduce the bacterial genome and the collections of genomic disturbed strains acquired, which were sufficiently reviewed previously. However, the common issue of growth decrease caused by genetic disturbance remains largely unaddressed. This mini-review discusses the considerable efforts made to improve growth fitness, which was decreased due to genome reduction. The proposal and perspective are clarified for further accumulated genetic deletion to minimise the Escherichia coli genome in terms of genome reduction, experimental evolution, medium optimization, and machine learning.
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Affiliation(s)
| | - Bei-Wen Ying
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Ibaraki, Japan
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9
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Hou F, Ke Z, Xu Y, Wang Y, Zhu G, Gao H, Ji S, Xu X. Systematic Large Fragment Deletions in the Genome of Synechococcus elongatus and the Consequent Changes in Transcriptomic Profiles. Genes (Basel) 2023; 14:genes14051091. [PMID: 37239451 DOI: 10.3390/genes14051091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Genome streamlining, as a natural process in the evolution of microbes, has become a common approach for generating ideal chassis cells for synthetic biology studies and industrial applications. However, systematic genome reduction remains a bottleneck in the generation of such chassis cells with cyanobacteria, due to very time-consuming genetic manipulations. Synechococcus elongatus PCC 7942, a unicellular cyanobacterium, is a candidate for systematic genome reduction, as its essential and nonessential genes have been experimentally identified. Here, we report that at least 20 of the 23 over 10 kb nonessential gene regions could be deleted and that stepwise deletions of these regions could be achieved. A septuple-deletion mutant (genome reduced by 3.8%) was generated, and the effects of genome reduction on the growth and genome-wide transcription were investigated. In the ancestral triple to sextuple mutants (b, c, d, e1), an increasingly large number of genes (up to 998) were upregulated relative to the wild type, while slightly fewer genes (831) were upregulated in the septuple mutant (f). In a different sextuple mutant (e2) derived from the quintuple mutant d, much fewer genes (232) were upregulated. Under the standard conditions in this study, the mutant e2 showed a higher growth rate than the wild type, e1 and f. Our results indicate that it is feasible to extensively reduce the genomes of cyanobacteria for generation of chassis cells and for experimental evolutionary studies.
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Affiliation(s)
- Feifei Hou
- College of Fisheries and Life Science, Dalian Ocean University, Dalian 116000, China
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Zhufang Ke
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yi Xu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yali Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Geqian Zhu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Hong Gao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Shuiling Ji
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Xudong Xu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
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10
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Marquez-Zavala E, Utrilla J. Engineering resource allocation in artificially minimized cells: Is genome reduction the best strategy? Microb Biotechnol 2023; 16:990-999. [PMID: 36808834 PMCID: PMC10128133 DOI: 10.1111/1751-7915.14233] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 01/26/2023] [Indexed: 02/20/2023] Open
Abstract
The elimination of the expression of cellular functions that are not needed in a certain well-defined artificial environment, such as those used in industrial production facilities, has been the goal of many cellular minimization projects. The generation of a minimal cell with reduced burden and less host-function interactions has been pursued as a tool to improve microbial production strains. In this work, we analysed two cellular complexity reduction strategies: genome and proteome reduction. With the aid of an absolute proteomics data set and a genome-scale model of metabolism and protein expression (ME-model), we quantitatively assessed the difference of reducing genome to the correspondence of reducing proteome. We compare the approaches in terms of energy consumption, defined in ATP equivalents. We aim to show what is the best strategy for improving resource allocation in minimized cells. Our results show that genome reduction by length is not proportional to reducing resource use. When we normalize calculated energy savings, we show that strains with the larger calculated proteome reduction show the largest resource use reduction. Furthermore, we propose that reducing highly expressed proteins should be the target as the translation of a gene uses most of the energy. The strategies proposed here should guide cell design when the aim of a project is to reduce the maximum amount or cellular resources.
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Affiliation(s)
- Elisa Marquez-Zavala
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway.,Synthetic Biology Program, Center for Genomic Sciences, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Jose Utrilla
- Synthetic Biology Program, Center for Genomic Sciences, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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11
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Mu X, Zhang F. Diverse mechanisms of bioproduction heterogeneity in fermentation and their control strategies. J Ind Microbiol Biotechnol 2023; 50:kuad033. [PMID: 37791393 PMCID: PMC10583207 DOI: 10.1093/jimb/kuad033] [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: 06/17/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023]
Abstract
Microbial bioproduction often faces challenges related to populational heterogeneity, where cells exhibit varying biosynthesis capabilities. Bioproduction heterogeneity can stem from genetic and non-genetic factors, resulting in decreased titer, yield, stability, and reproducibility. Consequently, understanding and controlling bioproduction heterogeneity are crucial for enhancing the economic competitiveness of large-scale biomanufacturing. In this review, we provide a comprehensive overview of current understandings of the various mechanisms underlying bioproduction heterogeneity. Additionally, we examine common strategies for controlling bioproduction heterogeneity based on these mechanisms. By implementing more robust measures to mitigate heterogeneity, we anticipate substantial enhancements in the scalability and stability of bioproduction processes. ONE-SENTENCE SUMMARY This review summarizes current understandings of different mechanisms of bioproduction heterogeneity and common control strategies based on these mechanisms.
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Affiliation(s)
- Xinyue Mu
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Division of Biological & Biomedical Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA
- Institute of Materials Science & Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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12
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Lao Z, Matsui Y, Ijichi S, Ying BW. Global coordination of the mutation and growth rates across the genetic and nutritional variety in Escherichia coli. Front Microbiol 2022; 13:990969. [PMID: 36204613 PMCID: PMC9530902 DOI: 10.3389/fmicb.2022.990969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/30/2022] [Indexed: 11/24/2022] Open
Abstract
Fitness and mutability are the primary traits of living organisms for adaptation and evolution. However, their quantitative linkage remained largely deficient. Whether there is any general relationship between the two features and how genetic and environmental variables influence them remained unclear and were addressed here. The mutation and growth rates of an assortment of Escherichia coli strain collections, including the wild-type strains and the genetically disturbed strains of either reduced genomes or deletion of the genes involved in the DNA replication fidelity, were evaluated in various media. The contribution of media to the mutation and growth rates was differentiated depending on the types of genetic disturbance. Nevertheless, the negative correlation between the mutation and growth rates was observed across the genotypes and was common in all media. It indicated the comprehensive association of the correlated mutation and growth rates with the genetic and medium variation. Multiple linear regression and support vector machine successfully predicted the mutation and growth rates and the categories of genotypes and media, respectively. Taken together, the study provided a quantitative dataset linking the mutation and growth rates, genotype, and medium and presented a simple and successful example of predicting bacterial growth and mutability by data-driven approaches.
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13
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Yang Q, Cai D, Chen W, Chen H, Luo W. Combined metabolic analyses for the biosynthesis pathway of l-threonine in Escherichia coli. Front Bioeng Biotechnol 2022; 10:1010931. [PMID: 36159692 PMCID: PMC9500239 DOI: 10.3389/fbioe.2022.1010931] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/15/2022] [Indexed: 11/18/2022] Open
Abstract
Currently, industrial production of l-threonine (Thr) is based on direct fermentation with microorganisms such as Escherichia coli, which has the characteristics of low cost and high productivity. In order to elucidate the key metabolic features of the synthesis pathway of Thr in E. coli to provide clues for metabolic regulation or engineering of the strain, this study was carried out on an l-threonine over-producing strain, in terms of analyses of metabolic flux, enzyme control and metabonomics. Since environmental disturbance and genetic modification are considered to be two important methods of metabolic analysis, addition of phosphate in the media and comparison of strains with different genotypes were selected as the two candidates due to their significant influence in the biosynthesis of Thr. Some important targets including key nodes, enzymes and biomarkers were identified, which may provide target sites for rational design through engineering the Thrproducing strain. Finally, metabolic regulation aimed at one biomarker identified in this study was set as an example, which confirms that combined metabolic analyses may guide to improve the production of threonine in E. coli.
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Affiliation(s)
- Qiang Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Wenshou Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Huiying Chen
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, China
| | - Wei Luo
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- *Correspondence: Wei Luo,
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14
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Hitomi K, Weng J, Ying BW. Contribution of the genomic and nutritional differentiation to the spatial distribution of bacterial colonies. Front Microbiol 2022; 13:948657. [PMID: 36081803 PMCID: PMC9448356 DOI: 10.3389/fmicb.2022.948657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
Colony growth is a common phenomenon of structured populations dispersed in nature; nevertheless, studies on the spatial distribution of colonies are largely insufficient. Here, we performed a systematic survey to address the questions of whether and how the spatial distribution of colonies was influenced by the genome and environment. Six Escherichia coli strains carrying either the wild-type or reduced genomes and eight media of varied nutritional richness were used to evaluate the genomic and environmental impacts, respectively. The genome size and nutritional variation contributed to the mean size and total area but not the variation and shape of size distribution of the colonies formed within the identical space and of equivalent spatial density. The spatial analysis by means of the Voronoi diagram found that the Voronoi correlation remained nearly constant in common, in comparison to the Voronoi response decreasing in correlation to genome reduction and nutritional enrichment. Growth analysis at the single colony level revealed positive correlations of the relative growth rate to both the maximal colony size and the Voronoi area, regardless of the genomic and nutritional variety. This result indicated fast growth for the large space assigned and supported homeostasis in the Voronoi correlation. Taken together, the spatial distribution of colonies might benefit efficient clonal growth. Although the mechanisms remain unclear, the findings provide quantitative insights into the genomic and environmental contributions to the growth and distribution of spatially or geographically isolated populations.
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15
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Cai M, Zhao Z, Li X, Xu Y, Xu M, Rao Z. Development of a nonauxotrophic L-homoserine hyperproducer in Escherichia coli by systems metabolic engineering. Metab Eng 2022; 73:270-279. [PMID: 35961600 DOI: 10.1016/j.ymben.2022.08.003] [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: 04/27/2022] [Revised: 07/14/2022] [Accepted: 08/03/2022] [Indexed: 11/19/2022]
Abstract
L-Homoserine is a valuable amino acid as a platform chemical in the synthesis of various important compounds. Development of microbial strains for high-level L-homoserine production is an attractive research direction in recent years. Herein, we converted a wild-type Escherichia coli to a non-auxotrophic and plasmid-free hyperproducer of L-homoserine using systematically metabolic engineer strategies. First, an initial strain was obtained through regulating L-homoserine degradation pathway and enhancing synthetic flow. To facilitate L-homoserine production, flux-control genes were tuned by optimizing the copy numbers in chromosome, and transport system was modified to promote L-homoserine efflux. Subsequently, a strategy of cofactors synergistic utilization was proposed and successfully applied to achieve L-homoserine hyperproduction. The final engineered strain could efficiently produce 85.29 g/L L-homoserine, which was the highest production level ever reported from a plasmid-free, antibiotic-free, inducer-free and nonauxotrophic strain. These strategies used here can be considered for developing microbial cell factory of other L-aspartate derivatives.
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Affiliation(s)
- Mengmeng Cai
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Zhenqiang Zhao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Xiangfei Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Yuanyi Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Meijuan Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China.
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16
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Dynamic Regulation of Transporter Expression to Increase L-Threonine Production Using L-Threonine Biosensors. FERMENTATION 2022. [DOI: 10.3390/fermentation8060250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The cytotoxicity of overexpressed transporters limits their application in biochemical production. To overcome this problem, we developed a feedback circuit for L-threonine production that uses a biosensor to regulate transporter expression. First, we used IPTG-induced rhtA regulation, L-threonine exporter, to simulate dynamic regulation for improving L-threonine production, and the results show that it had significant advantages compared with the constitutive overexpression of rhtA. To further construct a feedback circuit for rhtA auto-regulation, three L-threonine sensing promoters, PcysJ, PcysD, and PcysJH, were characterized with gradually decreasing strength. The dynamic expression of rhtA with a threonine-activated promoter considerably increased L-threonine production (21.19 g/L) beyond that attainable by the constitutive expression of rhtA (8.55 g/L). Finally, the autoregulation method was used in regulating rhtB and rhtC to improve L-threonine production and achieve a high titer of 26.78 g/L (a 161.01% increase), a yield of 0.627 g/g glucose, and a productivity of 0.743 g/L/h in shake-flask fermentation. This study analyzed in detail the influence of dynamic regulation and the constitutive expression of transporters on L-threonine production. For the first time, we confirmed that dynamically regulating transporter levels can efficiently promote L-threonine production by using the end-product biosensor.
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17
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Stukenberg D, Hoff J, Faber A, Becker A. NT-CRISPR, combining natural transformation and CRISPR-Cas9 counterselection for markerless and scarless genome editing in Vibrio natriegens. Commun Biol 2022; 5:265. [PMID: 35338236 PMCID: PMC8956659 DOI: 10.1038/s42003-022-03150-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 02/08/2022] [Indexed: 11/25/2022] Open
Abstract
The fast-growing bacterium Vibrio natriegens has recently gained increasing attention as a novel chassis organism for fundamental research and biotechnology. To fully harness the potential of this bacterium, highly efficient genome editing methods are indispensable to create strains tailored for specific applications. V. natriegens is able to take up free DNA and incorporate it into its genome by homologous recombination. This highly efficient natural transformation is able to mediate uptake of multiple DNA fragments, thereby allowing for multiple simultaneous edits. Here, we describe NT-CRISPR, a combination of natural transformation with CRISPR-Cas9 counterselection. In two temporally distinct steps, we first performed a genome edit by natural transformation and second, induced CRISPR-Cas9 targeting the wild type sequence, and thus leading to death of non-edited cells. Through cell killing with efficiencies of up to 99.999%, integration of antibiotic resistance markers became dispensable, enabling scarless and markerless edits with single-base precision. We used NT-CRISPR for deletions, integrations and single-base modifications with editing efficiencies of up to 100%. Further, we confirmed its applicability for simultaneous deletion of multiple chromosomal regions. Lastly, we showed that the near PAM-less Cas9 variant SpG Cas9 is compatible with NT-CRISPR and thereby broadens the target spectrum. Stukenberg et al. present NT-CRISPR, a method for performing genome editing in the marine bacterium Vibrio natriegens without using antibiotic resistance or other types of markers. This method combines V. natriegens’ capability for highly efficient natural transformation with an extremely efficient CRISPR-Cas9-based counterselection step for editing efficiencies of up to 100% and highly efficient simultaneous deletion of multiple sequences.
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Affiliation(s)
- Daniel Stukenberg
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany.,Department of Biology, Philipps-Universität Marburg, Marburg, Germany.,Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Josef Hoff
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany.,Department of Biology, Philipps-Universität Marburg, Marburg, Germany.,Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Anna Faber
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany.,Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Anke Becker
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany. .,Department of Biology, Philipps-Universität Marburg, Marburg, Germany.
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18
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Liu S, Xu JZ, Zhang WG. Advances and prospects in metabolic engineering of Escherichia coli for L-tryptophan production. World J Microbiol Biotechnol 2022; 38:22. [PMID: 34989926 DOI: 10.1007/s11274-021-03212-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
As an important raw material for pharmaceutical, food and feed industry, highly efficient production of L-tryptophan by Escherichia coli has attracted a considerable attention. However, there are complicated and multiple layers of regulation networks in L-tryptophan biosynthetic pathway and thus have difficulty to rewrite the biosynthetic pathway for producing L-tryptophan with high efficiency in E. coli. This review summarizes the biosynthetic pathway of L-tryptophan and highlights the main regulatory mechanisms in E. coli. In addition, we discussed the latest metabolic engineering strategies achieved in E. coli to reconstruct the L-tryptophan biosynthetic pathway. Moreover, we also review a few strategies that can be used in E. coli to improve robustness and streamline of L-tryptophan high-producing strains. Lastly, we also propose the potential strategies to further increase L-tryptophan production by systematic metabolic engineering and synthetic biology techniques.
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Affiliation(s)
- Shuai Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China
| | - Jian-Zhong Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
| | - Wei-Guo Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
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19
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Advances in microbial production of feed amino acid. ADVANCES IN APPLIED MICROBIOLOGY 2022; 119:1-33. [DOI: 10.1016/bs.aambs.2022.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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20
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Appelbaum M, Schweder T. Metabolic Engineering of
Bacillus
– New Tools, Strains, and Concepts. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Ahmed MS, Lauersen KJ, Ikram S, Li C. Efflux Transporters' Engineering and Their Application in Microbial Production of Heterologous Metabolites. ACS Synth Biol 2021; 10:646-669. [PMID: 33751883 DOI: 10.1021/acssynbio.0c00507] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolic engineering of microbial hosts for the production of heterologous metabolites and biochemicals is an enabling technology to generate meaningful quantities of desired products that may be otherwise difficult to produce by traditional means. Heterologous metabolite production can be restricted by the accumulation of toxic products within the cell. Efflux transport proteins (transporters) provide a potential solution to facilitate the export of these products, mitigate toxic effects, and enhance production. Recent investigations using knockout lines, heterologous expression, and expression profiling of transporters have revealed candidates that can enhance the export of heterologous metabolites from microbial cell systems. Transporter engineering efforts have revealed that some exhibit flexible substrate specificity and may have broader application potentials. In this Review, the major superfamilies of efflux transporters, their mechanistic modes of action, selection of appropriate efflux transporters for desired compounds, and potential transporter engineering strategies are described for potential applications in enhancing engineered microbial metabolite production. Future studies in substrate recognition, heterologous expression, and combinatorial engineering of efflux transporters will assist efforts to enhance heterologous metabolite production in microbial hosts.
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Affiliation(s)
- Muhammad Saad Ahmed
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology (BIT), Beijing 100081, P. R. China
- Department of Biological Sciences, National University of Medical Sciences (NUMS), Abid Majeed Road, The Mall, Rawalpindi 46000, Pakistan
| | - Kyle J. Lauersen
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Kingdom of Saudi Arabia
| | - Sana Ikram
- Beijing Higher Institution Engineering Research Center for Food Additives and Ingredients, Beijing Technology & Business University (BTBU), Beijing 100048, P. R. China
| | - Chun Li
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology (BIT), Beijing 100081, P. R. China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, P. R. China
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China
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22
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Wang J, Ma W, Wang X. Insights into the structure of Escherichia coli outer membrane as the target for engineering microbial cell factories. Microb Cell Fact 2021; 20:73. [PMID: 33743682 PMCID: PMC7980664 DOI: 10.1186/s12934-021-01565-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/12/2021] [Indexed: 12/16/2022] Open
Abstract
Escherichia coli is generally used as model bacteria to define microbial cell factories for many products and to investigate regulation mechanisms. E. coli exhibits phospholipids, lipopolysaccharides, colanic acid, flagella and type I fimbriae on the outer membrane which is a self-protective barrier and closely related to cellular morphology, growth, phenotypes and stress adaptation. However, these outer membrane associated molecules could also lead to potential contamination and insecurity for fermentation products and consume lots of nutrients and energy sources. Therefore, understanding critical insights of these membrane associated molecules is necessary for building better microbial producers. Here the biosynthesis, function, influences, and current membrane engineering applications of these outer membrane associated molecules were reviewed from the perspective of synthetic biology, and the potential and effective engineering strategies on the outer membrane to improve fermentation features for microbial cell factories were suggested.
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Affiliation(s)
- Jianli Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory On Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Wenjian Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,Science Center for Future Foods, Jiangnan University, Wuxi, 214122, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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23
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Exploring the fitness benefits of genome reduction in Escherichia coli by a selection-driven approach. Sci Rep 2020; 10:7345. [PMID: 32355292 PMCID: PMC7193553 DOI: 10.1038/s41598-020-64074-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/08/2020] [Indexed: 11/26/2022] Open
Abstract
Artificial simplification of bacterial genomes is thought to have the potential to yield cells with reduced complexity, enhanced genetic stability, and improved cellular economy. Of these goals, economical gains, supposedly due to the elimination of superfluous genetic material, and manifested in elevated growth parameters in selected niches, have not yet been convincingly achieved. This failure might stem from limitations of the targeted genome reduction approach that assumes full knowledge of gene functions and interactions, and allows only a limited number of reduction trajectories to interrogate. To explore the potential fitness benefits of genome reduction, we generated successive random deletions in E. coli by a novel, selection-driven, iterative streamlining process. The approach allows the exploration of multiple streamlining trajectories, and growth periods inherent in the procedure ensure selection of the fittest variants of the population. By generating single- and multiple-deletion strains and reconstructing the deletions in the parental genetic background, we showed that favourable deletions can be obtained and accumulated by the procedure. The most reduced multiple-deletion strain, obtained in five deletion cycles (2.5% genome reduction), outcompeted the wild-type, and showed elevated biomass yield. The spectrum of advantageous deletions, however, affecting only a few genomic regions, appears to be limited.
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24
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Du H, Zhao Y, Wu F, Ouyang P, Chen J, Jiang X, Ye J, Chen GQ. Engineering Halomonas bluephagenesis for L-Threonine production. Metab Eng 2020; 60:119-127. [PMID: 32315761 DOI: 10.1016/j.ymben.2020.04.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/06/2020] [Accepted: 04/13/2020] [Indexed: 12/13/2022]
Abstract
Halophilic Halomonas bluephagenesis (H. bluephagenesis), a chassis for cost-effective Next Generation Industrial Biotechnology (NGIB), was for the first time engineered to successfully produce L-threonine, one of the aspartic family amino acids (AFAAs). Five exogenous genes including thrA*BC, lysC* and rhtC encoding homoserine dehydrogenase mutant at G433R, homoserine kinase, L-threonine synthase, aspartokinase mutant at T344M, S345L and T352I, and export transporter of threonine, respectively, were grouped into two expression modules for transcriptional tuning on plasmid- and chromosome-based systems in H. bluephagenesis, respectively, after pathway tuning debugging. Combined with deletion of import transporter or/and L-threonine dehydrogenase encoded by sstT or/and thd, respectively, the resulting recombinant H. bluephagenesis TDHR3-42-p226 produced 7.5 g/L and 33 g/L L-threonine when grown under open unsterile conditions in shake flasks and in a 7 L bioreactor, respectively. Engineering H. bluephagenesis demonstrates strong potential for production of diverse metabolic chemicals.
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Affiliation(s)
- Hetong Du
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
| | - Yiqing Zhao
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
| | - Fuqing Wu
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
| | - Peifei Ouyang
- China Fortune Land Development Industrial Investment Co. Ltd., Beijing, 100027, China; Research Center for Healthcare Management, School of Economics and Management, Tsinghua University, China
| | - Jinchun Chen
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China
| | - Xiaoran Jiang
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China.
| | - Jianwen Ye
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China.
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Bioinformatics, Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China; MOE Key Lab of Industrial Biocatalysis, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
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25
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Zhao L, Lu Y, Yang J, Fang Y, Zhu L, Ding Z, Wang C, Ma W, Hu X, Wang X. Expression regulation of multiple key genes to improve L-threonine in Escherichia coli. Microb Cell Fact 2020; 19:46. [PMID: 32093713 PMCID: PMC7041290 DOI: 10.1186/s12934-020-01312-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/18/2020] [Indexed: 11/28/2022] Open
Abstract
Background Escherichia coli is an important strain for l-threonine production. Genetic switch is a ubiquitous regulatory tool for gene expression in prokaryotic cells. To sense and regulate intracellular or extracellular chemicals, bacteria evolve a variety of transcription factors. The key enzymes required for l-threonine biosynthesis in E. coli are encoded by the thr operon. The thr operon could coordinate expression of these genes when l-threonine is in short supply in the cell. Results The thrL leader regulatory elements were applied to regulate the expression of genes iclR, arcA, cpxR, gadE, fadR and pykF, while the threonine-activating promoters PcysH, PcysJ and PcysD were applied to regulate the expression of gene aspC, resulting in the increase of l-threonine production in an l-threonine producing E. coli strain TWF001. Firstly, different parts of the regulator thrL were inserted in the iclR regulator region in TWF001, and the best resulting strain TWF063 produced 16.34 g l-threonine from 40 g glucose after 30 h cultivation. Secondly, the gene aspC following different threonine-activating promoters was inserted into the chromosome of TWF063, and the best resulting strain TWF066 produced 17.56 g l-threonine from 40 g glucose after 30 h cultivation. Thirdly, the effect of expression regulation of arcA, cpxR, gadE, pykF and fadR was individually investigated on l-threonine production in TWF001. Finally, using TWF066 as the starting strain, the expression of genes arcA, cpxR, gadE, pykF and fadR was regulated individually or in combination to obtain the best strain for l-threonine production. The resulting strain TWF083, in which the expression of seven genes (iclR, aspC, arcA, cpxR, gadE, pykF, fadR and aspC) was regulated, produced 18.76 g l-threonine from 30 g glucose, 26.50 g l-threonine from 40 g glucose, or 26.93 g l-threonine from 50 g glucose after 30 h cultivation. In 48 h fed-batch fermentation, TWF083 could produce 116.62 g/L l‐threonine with a yield of 0.486 g/g glucose and productivity of 2.43 g/L/h. Conclusion The genetic engineering through the expression regulation of key genes is a better strategy than simple deletion of these genes to improve l-threonine production in E. coli. This strategy has little effect on the intracellular metabolism in the early stage of the growth but could increase l-threonine biosynthesis in the late stage.
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Affiliation(s)
- Lei Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Ying Lu
- Nanjing Customs District P. R. China, Wuxi, 214122, China
| | - Jun Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Yu Fang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Lifei Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Zhixiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Chenhui Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Wenjian Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiaoqing Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China. .,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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Engineering Biology to Construct Microbial Chassis for the Production of Difficult-to-Express Proteins. Int J Mol Sci 2020; 21:ijms21030990. [PMID: 32024292 PMCID: PMC7037952 DOI: 10.3390/ijms21030990] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/28/2020] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
A large proportion of the recombinant proteins manufactured today rely on microbe-based expression systems owing to their relatively simple and cost-effective production schemes. However, several issues in microbial protein expression, including formation of insoluble aggregates, low protein yield, and cell death are still highly recursive and tricky to optimize. These obstacles are usually rooted in the metabolic capacity of the expression host, limitation of cellular translational machineries, or genetic instability. To this end, several microbial strains having precisely designed genomes have been suggested as a way around the recurrent problems in recombinant protein expression. Already, a growing number of prokaryotic chassis strains have been genome-streamlined to attain superior cellular fitness, recombinant protein yield, and stability of the exogenous expression pathways. In this review, we outline challenges associated with heterologous protein expression, some examples of microbial chassis engineered for the production of recombinant proteins, and emerging tools to optimize the expression of heterologous proteins. In particular, we discuss the synthetic biology approaches to design and build and test genome-reduced microbial chassis that carry desirable characteristics for heterologous protein expression.
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27
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Zhao L, Zhang H, Wang X, Han G, Ma W, Hu X, Li Y. Transcriptomic analysis of an l-threonine-producing Escherichia coli TWF001. Biotechnol Appl Biochem 2020; 67:414-429. [PMID: 31976571 DOI: 10.1002/bab.1890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/21/2020] [Indexed: 01/10/2023]
Abstract
Wild-type Escherichia coli usually does not accumulate l-threonine, but E. coli strain TWF001 could produce 30.35 g/L l-threonine after 23-H fed-batch fermentation. To understand the mechanism for the high yield of l-threonine production in TWF001, transcriptomic analyses of the TWF001 cell samples collected at the logarithmic and stationary phases were performed, using the wild-type E. coli strain W3110 as the control. Compared with W3110, 1739 and 2361 genes were differentially transcribed in the logarithmic and stationary phases, respectively. Most genes related to the biosynthesis of l-threonine were significantly upregulated. Some key genes related to the NAD(P)H regeneration were upregulated. Many genes relevant to glycolysis and TCA cycle were downregulated. The key genes involved in the l-threonine degradation were downregulated. The gene rhtA encoding the l-threonine exporter was upregulated, whereas the genes sstT and tdcC encoding the l-threonine importer were downregulated. The upregulated genes in the glutamate pathway might form an amino-providing loop, which is beneficial for the high yield of l-threonine production. Many genes encoding the 30S and 50S subunits of ribosomes were also upregulated. The findings are useful for gene engineering to increase l-threonine production in E. coli.
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Affiliation(s)
- Lei Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Hailing Zhang
- Department of Biological Engineering, College of Life Science, Yantai University, Shandong, 408100, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Guoqiang Han
- College of Modern Agriculture and Biological Engineering, Yangtze Normal University, Chongqing, 264005, China
| | - Wenjian Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiaoqing Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Ye Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China
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28
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Kurokawa M, Ying BW. Experimental Challenges for Reduced Genomes: The Cell Model Escherichia coli. Microorganisms 2019; 8:E3. [PMID: 31861355 PMCID: PMC7022904 DOI: 10.3390/microorganisms8010003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/11/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
Genome reduction, as a top-down approach to obtain the minimal genetic information essential for a living organism, has been conducted with bacterial cells for decades. The most popular and well-studied cell models for genome reduction are Escherichia coli strains. As the previous literature intensively introduced the genetic construction and application of the genome-reduced Escherichia coli strains, the present review focuses the design principles and compares the reduced genome collections from the specific viewpoint of growth, which represents a fundamental property of living cells and is an important feature for their biotechnological application. For the extended simplification of the genomic sequences, the approach of experimental evolution and concern for medium optimization are newly proposed. The combination of the current techniques of genomic construction and the newly proposed methodologies could allow us to acquire growing Escherichia coli cells carrying the extensively reduced genome and to address the question of what the minimal genome essential for life is.
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Affiliation(s)
| | - Bei-Wen Ying
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 305-8572 Ibaraki, Japan;
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29
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Wynands B, Otto M, Runge N, Preckel S, Polen T, Blank LM, Wierckx N. Streamlined Pseudomonas taiwanensis VLB120 Chassis Strains with Improved Bioprocess Features. ACS Synth Biol 2019; 8:2036-2050. [PMID: 31465206 DOI: 10.1021/acssynbio.9b00108] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Microbes harbor many traits that are dispensable or even unfavorable under industrial and laboratory settings. The elimination of such traits could improve the host's efficiency, genetic stability, and robustness, thereby increasing the predictability and boosting its performance as a microbial cell factory. We engineered solvent-tolerant Pseudomonas taiwanensis VLB120 to yield streamlined chassis strains with higher growth rates and biomass yields, enhanced solvent tolerance, and improved process performance. In total, the genome was reduced by up to 10%. This was achieved by the elimination of genes that enable the cell to swim and form biofilms and by the deletion of the megaplasmid pSTY and large proviral segments. The resulting strain GRC1 had a 15% higher growth rate and biomass yield than the wildtype. However, this strain lacks the pSTY-encoded efflux pump TtgGHI, rendering it solvent-sensitive. Through reintegration of ttgGHI by chromosomal insertion without (GRC2) and with (GRC3) the corresponding regulator genes, the solvent-tolerant phenotype was enhanced. The generated P. taiwanensis GRC strains enlarge the repertoire of streamlined chassis with enhanced key performance indicators, making them attractive hosts for biotechnological applications. The different solvent tolerance levels of GRC1, GRC2, and GRC3 enable the selection of a fitting host platform in relation to the desired process requirements in a chassis à la carte principle. This was demonstrated in a metabolic engineering approach for the production of phenol from glycerol. The streamlined producer GRC1Δ5-TPL38 outperformed the equivalent nonstreamlined producer VLB120Δ5-TPL38 concerning phenol titer, rate, and yield, thereby highlighting the added value of the streamlined chassis.
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Affiliation(s)
- Benedikt Wynands
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Maike Otto
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Nadine Runge
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Sarah Preckel
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Tino Polen
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Lars M. Blank
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Nick Wierckx
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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30
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Zhu L, Fang Y, Ding Z, Zhang S, Wang X. Developing an l-threonine-producing strain from wild-type Escherichia coli by modifying the glucose uptake, glyoxylate shunt, and l-threonine biosynthetic pathway. Biotechnol Appl Biochem 2019; 66:962-976. [PMID: 31486127 DOI: 10.1002/bab.1813] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/03/2019] [Indexed: 12/20/2022]
Abstract
Wild-type Escherichia coli MG1655 usually does not accumulate l-threonine. In this study, the effects of 13 genes related to the glucose uptake, glycolysis, TCA cycle, l-threonine biosynthesis, or their regulation on l-threonine accumulation in E. coli MG1655 were investigated. Sixteen E. coli mutant strains were constructed by chromosomal deletion or overexpression of one or more genes of rsd, ptsG, ptsH, ptsI, crr, galP, glk, iclR, and gltA; the plasmid pFW01-thrA*BC-rhtC harboring the key genes for l-threonine biosynthesis and secretion was introduced into these mutants. The analyses on cell growth, glucose consumption, and l-threonine production of these recombinant strains showed that most of these strains could accumulate l-threonine, and the highest yield was obtained in WMZ016/pFW01-thrA*BC-rhtC. WMZ016 was derived from MG1655 by deleting crr and iclR and enhancing the expression of gltA. WMZ016/pFW01-thrA*BC-rhtC could produce 17.98 g/L l-threonine with a yield of 0.346 g/g glucose, whereas the control strain MG1655/pFW01-thrA*BC-rhtC could only produce 0.68 g/L l-threonine. In addition, WMZ016/pFW01-thrA*BC-rhtC could tolerate the high concentration of glucose and produced no detectable by-products; therefore, it should be an ideal platform strain for further development. The results indicate that manipulating the glucose uptake and TCA cycle could efficiently increase l-threonine production in E. coli.
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Affiliation(s)
- Lifei Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yu Fang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zhixiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Shuyan Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
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31
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Ding Z, Fang Y, Zhu L, Wang J, Wang X. Deletion of arcA, iclR, and tdcC in Escherichia coli to improve l-threonine production. Biotechnol Appl Biochem 2019; 66:794-807. [PMID: 31177569 DOI: 10.1002/bab.1789] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/06/2019] [Indexed: 11/06/2022]
Abstract
l-Threonine is an important amino acid supplemented in food, medicine, or feed. Starting from glucose, l-threonine production in Escherichia coli involves the glycolysis, TCA cycle, and the l-threonine biosynthetic pathway. In this study, how the l-threonine production in an l-threonine producing E. coli TWF001 is controlled by the three regulators ArcA, Cra, and IclR, which control the expression of genes involved in the glycolysis and TCA cycle, has been investigated. Ten mutant strains were constructed from TWF001 by different combinations of deletion or overexpression of arcA, cra, iclR, and tdcC. l-Threonine production was increased in the mutants TWF015 (ΔarcAΔcra), TWF016 (ΔarcAPcra::Ptrc), TWF017 (ΔarcAΔiclR), TWF018 (ΔarcAΔiclRΔtdcC), and TWF019 (ΔarcAΔcraΔiclRΔtdcC). Among these mutant strains, the highest l-threonine production (26.0 g/L) was obtained in TWF018, which was a 109.7% increase compared with the control TWF001. In addition, TWF018 could consume glucose more efficiently than TWF001 and produce less acetate. The results suggest that deletion of arcA, iclR, and tdcC could efficiently increase l-threonine production in E. coli.
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Affiliation(s)
- Zhixiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Yu Fang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Lifei Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Jianli Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, People's Republic of China
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32
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Zhao L, Hu X, Li Y, Wang Z, Wang X. Construction of a novel Escherichia coli expression system: relocation of lpxA from chromosome to a constitutive expression vector. Appl Microbiol Biotechnol 2019; 103:7177-7189. [PMID: 31317228 DOI: 10.1007/s00253-019-10013-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/22/2019] [Accepted: 07/05/2019] [Indexed: 11/26/2022]
Abstract
The selective marker in the plasmid-based expression system is usually a gene that encodes an antibiotic-resistant protein; therefore, the antibiotic has to add to maintain the plasmid when growing the bacteria. This antibiotic addition would lead to increase of production cost and the environment contamination. In this study, a novel Escherichia coli expression system, the lpxA deletion mutant harboring an lpxA-carrying vector, was developed. To develop this system, three plasmids pCas9Cre, pTF-A-UD, and pRSFCmlpxA were constructed. The plasmid pCas9Cre produces enzymes Cas9, λ-Red, and Cre and can be cured by growing at 42 °C; pTF-A-UD contains several DNA fragments required for deleting the chromosomal lpxA and can be cured by adding isopropyl-D-thiogalactopyranoside; pRSFCmlpxA contains the lpxA mutant lpxA123 and CamR. When E. coli were transformed with these three plasmids, the chromosomal lpxA and the CamR in pRSFCmlpxA can be efficiently removed, resulting in an E. coli lpxA mutant harboring pRSFlpxA. The lpxA is essential for the growth of E. coli; its relocation from chromosome to a constitutive expression vector is an ideal strategy to maintain the vector without antibiotic addition. The lpxA123 in pRSFlpxA can complement the deletion of the chromosomal lpxA and provide a strong selective pressure to maintain the plasmid pRSFlpxA. This study provides an experimental evidence that this novel expression system is convenient and efficient to use and can be used to improve L-threonine biosynthesis in the wild type E. coli MG1655 and an L-threonine producing E. coli TWF006.
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Affiliation(s)
- Lei Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiaoqing Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Ye Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Zhen Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China.
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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33
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Wang J, Ma W, Fang Y, Yang J, Zhan J, Chen S, Wang X. Increasing L-threonine production in Escherichia coli by overexpressing the gene cluster phaCAB. J Ind Microbiol Biotechnol 2019; 46:1557-1568. [PMID: 31312942 DOI: 10.1007/s10295-019-02215-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
Abstract
L-Threonine is an important branched-chain amino acid and could be applied in feed, drugs, and food. In this study, L-threonine production in an L-threonine-producing Escherichia coli strain TWF001 was significantly increased by overexpressing the gene cluster phaCAB from Ralstonia eutropha. TWF001/pFW01-phaCAB could produce 96.4-g/L L-threonine in 3-L fermenter and 133.5-g/L L-threonine in 10-L fermenter, respectively. In addition, TWF001/pFW01-phaCAB produced 216% more acetyl-CoA, 43% more malate, and much less acetate than the vector control TWF001/pFW01, and meanwhile, TWF001/pFW01-phaCAB produced poly-3-hydroxybutyrate, while TWF001/pFW01 did not. Transcription analysis showed that the key genes in the L-threonine biosynthetic pathway were up-regulated, the genes relevant to the acetate formation were down-regulated, and the gene acs encoding the enzyme which converts acetate to acetyl-CoA was up-regulated. The results suggested that overexpression of the gene cluster phaCAB in E. coli benefits the enhancement of L-threonine production.
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Affiliation(s)
- Jianli Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Wenjian Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Yu Fang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Jun Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Jie Zhan
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Shangwei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China. .,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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34
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Liu S, Xiao H, Zhang F, Lu Z, Zhang Y, Deng A, Li Z, Yang C, Wen T. A seamless and iterative DNA assembly method named PS-Brick and its assisted metabolic engineering for threonine and 1-propanol production. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:180. [PMID: 31338122 PMCID: PMC6628500 DOI: 10.1186/s13068-019-1520-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/03/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND DNA assembly is an essential technique enabling metabolic engineering and synthetic biology. Combining novel DNA assembly technologies with rational metabolic engineering can facilitate the construction of microbial cell factories. Amino acids and derived biochemicals are important products in industrial biotechnology with wide application and huge markets. DNA assembly scenarios encountered in metabolic engineering for the construction of amino acid and related compound producers, such as design-build-test-learn cycles, construction of precise genetic circuits and repetitive DNA molecules, usually require for iterative, scarless and repetitive sequence assembly methods, respectively. RESULTS Restriction endonuclease (RE)-assisted strategies constitute one of the major categories of DNA assembly. Here, we developed a Type IIP and IIS RE-assisted method named PS-Brick that comprehensively takes advantage of the properties of PCR fragments and REs for iterative, seamless and repetitive sequence assembly. One round of PS-Brick reaction using purified plasmids and PCR fragments was accomplished within several hours, and transformation of the resultant reaction product from this PS-Brick assembly reaction exhibited high efficiency (104-105 CFUs/µg DNA) and high accuracy (~ 90%). An application of metabolic engineering to threonine production, including the release of feedback regulation, elimination of metabolic bottlenecks, intensification of threonine export and inactivation of threonine catabolism, was stepwise resolved in E. coli by rounds of "design-build-test-learn" cycles through the iterative PS-Brick paradigm, and 45.71 g/L threonine was obtained through fed-batch fermentation. In addition to the value of the iterative character of PS-Brick for sequential strain engineering, seamless cloning enabled precise in-frame fusion for codon saturation mutagenesis and bicistronic design, and the repetitive sequence cloning ability of PS-Brick enabled construction of tandem CRISPR sgRNA arrays for genome editing. Moreover, the heterologous pathway deriving 1-propanol pathway from threonine, composed of Lactococcus lactis kivD and Saccharomyces cerevisiae ADH2, was assembled by one cycle of PS-Brick, resulting in 1.35 g/L 1-propanol in fed-batch fermentation. CONCLUSIONS To the best of our knowledge, the PS-Brick framework is the first RE-assisted DNA assembly method using the strengths of both Type IIP and IIS REs. In this study, PS-Brick was demonstrated to be an efficient DNA assembly method for pathway construction and genome editing and was successfully applied in design-build-test-learn (DBTL) cycles of metabolic engineering for the production of threonine and threonine-derived 1-propanol. The PS-Brick presents a valuable addition to the current toolbox of synthetic biology and metabolic engineering.
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Affiliation(s)
- Shuwen Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Haihan Xiao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Fangfang Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- Institute of Physical Science and Information Technology, Anhui University, Hefei, 230039 China
| | - Zheng Lu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yun Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Aihua Deng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Zhongcai Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Cui Yang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Tingyi Wen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049 China
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35
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Landon S, Rees-Garbutt J, Marucci L, Grierson C. Genome-driven cell engineering review: in vivo and in silico metabolic and genome engineering. Essays Biochem 2019; 63:267-284. [PMID: 31243142 PMCID: PMC6610458 DOI: 10.1042/ebc20180045] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/19/2019] [Accepted: 05/23/2019] [Indexed: 01/04/2023]
Abstract
Producing 'designer cells' with specific functions is potentially feasible in the near future. Recent developments, including whole-cell models, genome design algorithms and gene editing tools, have advanced the possibility of combining biological research and mathematical modelling to further understand and better design cellular processes. In this review, we will explore computational and experimental approaches used for metabolic and genome design. We will highlight the relevance of modelling in this process, and challenges associated with the generation of quantitative predictions about cell behaviour as a whole: although many cellular processes are well understood at the subsystem level, it has proved a hugely complex task to integrate separate components together to model and study an entire cell. We explore these developments, highlighting where computational design algorithms compensate for missing cellular information and underlining where computational models can complement and reduce lab experimentation. We will examine issues and illuminate the next steps for genome engineering.
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Affiliation(s)
- Sophie Landon
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K
- Department of Engineering Mathematics, University of Bristol, Bristol BS8 1UB, U.K
| | - Joshua Rees-Garbutt
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, U.K
| | - Lucia Marucci
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K.
- Department of Engineering Mathematics, University of Bristol, Bristol BS8 1UB, U.K
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1UB, U.K
| | - Claire Grierson
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K.
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, U.K
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36
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Yang J, Fang Y, Wang J, Wang C, Zhao L, Wang X. Deletion of regulator-encoding genes fadR, fabR and iclR to increase L-threonine production in Escherichia coli. Appl Microbiol Biotechnol 2019; 103:4549-4564. [DOI: 10.1007/s00253-019-09818-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/19/2019] [Accepted: 03/31/2019] [Indexed: 12/25/2022]
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Xu JM, Li JQ, Zhang B, Liu ZQ, Zheng YG. Fermentative production of the unnatural amino acid L-2-aminobutyric acid based on metabolic engineering. Microb Cell Fact 2019; 18:43. [PMID: 30819198 PMCID: PMC6393993 DOI: 10.1186/s12934-019-1095-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 02/25/2019] [Indexed: 01/13/2023] Open
Abstract
Background l-2-aminobutyric acid (l-ABA) is an unnatural amino acid that is a key intermediate for the synthesis of several important pharmaceuticals. To make the biosynthesis of l-ABA environmental friendly and more suitable for the industrial-scale production. We expand the nature metabolic network of Escherichia coli using metabolic engineering approach for the production of l-ABA. Results In this study, Escherichia coli THR strain with a modified pathway for threonine-hyperproduction was engineered via deletion of the rhtA gene from the chromosome. To redirect carbon flux from 2-ketobutyrate (2-KB) to l-ABA, the ilvIH gene was deleted to block the l-isoleucine pathway. Furthermore, the ilvA gene from Escherichia coli W3110 and the leuDH gene from Thermoactinomyces intermedius were amplified and co-overexpressed. The promoter was altered to regulate the expression strength of ilvA* and leuDH. The final engineered strain E. coli THR ΔrhtAΔilvIH/Gap-ilvA*-Pbs-leuDH was able to produce 9.33 g/L of l-ABA with a yield of 0.19 g/L/h by fed-batch fermentation in a 5 L bioreactor. Conclusions This novel metabolically tailored strain offers a promising approach to fulfill industrial requirements for production of l-ABA. Electronic supplementary material The online version of this article (10.1186/s12934-019-1095-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian-Miao Xu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Jian-Qiang Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Bo Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Zhi-Qiang Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
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Liu J, Li H, Xiong H, Xie X, Chen N, Zhao G, Caiyin Q, Zhu H, Qiao J. Two-stage carbon distribution and cofactor generation for improving l-threonine production of Escherichia coli. Biotechnol Bioeng 2018; 116:110-120. [PMID: 30252940 DOI: 10.1002/bit.26844] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/09/2018] [Accepted: 09/21/2018] [Indexed: 12/14/2022]
Abstract
L-Threonine, a kind of essential amino acid, has numerous applications in food, pharmaceutical, and aquaculture industries. Fermentative l-threonine production from glucose has been achieved in Escherichia coli. However, there are still several limiting factors hindering further improvement of l-threonine productivity, such as the conflict between cell growth and production, byproduct accumulation, and insufficient availability of cofactors (adenosine triphosphate, NADH, and NADPH). Here, a metabolic modification strategy of two-stage carbon distribution and cofactor generation was proposed to address the above challenges in E. coli THRD, an l-threonine producing strain. The glycolytic fluxes towards tricarboxylic acid cycle were increased in growth stage through heterologous expression of pyruvate carboxylase, phosphoenolpyruvate carboxykinase, and citrate synthase, leading to improved glucose utilization and growth performance. In the production stage, the carbon flux was redirected into l-threonine synthetic pathway via a synthetic genetic circuit. Meanwhile, to sustain the transaminase reaction for l-threonine production, we developed an l-glutamate and NADPH generation system through overexpression of glutamate dehydrogenase, formate dehydrogenase, and pyridine nucleotide transhydrogenase. This strategy not only exhibited 2.02- and 1.21-fold increase in l-threonine production in shake flask and bioreactor fermentation, respectively, but had potential to be applied in the production of many other desired oxaloacetate derivatives, especially those involving cofactor reactions.
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Affiliation(s)
- Jiaheng Liu
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University, Tianjin, China
| | - Huiling Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University, Tianjin, China
| | - Hui Xiong
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University, Tianjin, China
| | - Xixian Xie
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin, China
| | - Ning Chen
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin, China
| | - Guangrong Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University, Tianjin, China
| | - Qinggele Caiyin
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Hongji Zhu
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Jianjun Qiao
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.,School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University, Tianjin, China
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Martínez-Carranza E, Barajas H, Alcaraz LD, Servín-González L, Ponce-Soto GY, Soberón-Chávez G. Variability of Bacterial Essential Genes Among Closely Related Bacteria: The Case of Escherichia coli. Front Microbiol 2018; 9:1059. [PMID: 29910775 PMCID: PMC5992433 DOI: 10.3389/fmicb.2018.01059] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/04/2018] [Indexed: 11/23/2022] Open
Abstract
The definition of bacterial essential genes has been widely pursued using different approaches. Their study has impacted several fields of research such as synthetic biology, the construction of bacteria with minimal chromosomes, the search for new antibiotic targets, or the design of strains with biotechnological applications. Bacterial genomes are mosaics that only share a small subset of gene-sequences (core genome) even among members of the same species. It has been reported that the presence of essential genes is highly variable between closely related bacteria and even among members of the same species, due to the phenomenon known as “non-orthologous gene displacement” that refers to the coding for an essential function by genes with no sequence homology due to horizontal gene transfer (HGT). The existence of dormant forms among bacteria and the high incidence of HGT have been proposed to be driving forces of bacterial evolution, and they might have a role in the low level of conservation of essential genes among related bacteria by non-orthologous gene displacement, but this correlation has not been recognized. The aim of this mini-review is to give a brief overview of the approaches that have been taken to define and study essential genes, and the implications of non-orthologous gene displacement in bacterial evolution, focusing mainly in the case of Escherichia coli. To this end, we reviewed the available literature, and we searched for the presence of the essential genes defined by mutagenesis in the genomes of the 63 best-sequenced E. coli genomes that are available in NCBI database. We could not document specific cases of non-orthologous gene displacement among the E. coli strains analyzed, but we found that the quality of the genome-sequences in the database is not enough to make accurate predictions about the conservation of essential-genes among members of this bacterial species.
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Affiliation(s)
- Enrique Martínez-Carranza
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Hugo Barajas
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis-David Alcaraz
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis Servín-González
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gabriel-Yaxal Ponce-Soto
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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40
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Zhao H, Fang Y, Wang X, Zhao L, Wang J, Li Y. Increasing L-threonine production in Escherichia coli by engineering the glyoxylate shunt and the L-threonine biosynthesis pathway. Appl Microbiol Biotechnol 2018; 102:5505-5518. [PMID: 29713792 DOI: 10.1007/s00253-018-9024-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 03/20/2018] [Accepted: 04/13/2018] [Indexed: 11/29/2022]
Abstract
L-threonine is an important amino acid that can be added in food, medicine, or feed. Here, the influence of glyoxylate shunt on an L-threonine producing strain Escherichia coli TWF001 has been studied. The gene iclR was deleted, and the native promoter of the aceBA operon was replaced by the trc promoter in the chromosome of TWF001, the resulting strainTWF004 could produce 0.39 g L-threonine from1 g glucose after 36-h flask cultivation. Further replacing the native promoter of aspC by the trc promoter in the chromosome of TWF004 resulted in the strain TWF006. TWF006 could produce 0.42 g L-threonine from 1 g glucose after 36-h flask cultivation. Three key genes in the biosynthetic pathway of L-threonine, thrA * (a mutated thrA), thrB, and thrC were overexpressed in TWF006, resulting the strain TWF006/pFW01-thrA * BC. TWF006/pFW01-thrA * BC could produce 0.49 g L-threonine from 1 g glucose after 36-h flask cultivation. Next, the genes asd, rhtA, rhtC, or thrE were inserted into the plasmid TWF006/pFW01-thrA * BC, and TWF006 was transformed with these plasmids, resulting the strains TWF006/pFW01-thrA * BC-asd, TWF006/pFW01-thrA * BC-rhtA, TWF006/pFW01-thrA * BC-rhtC, and TWF006/pFW01-thrA * BC-thrE, respectively. These four strains could produce more L-threonine than the control strain, and the highest yield was produced by TWF006/pFW01-thrA * BC-asd; after 36-h flask cultivation, TWF006/pFW01-thrA * BC-asd could produce 15.85 g/l L-threonine, i.e., 0.53 g L-threonine per 1 g glucose, which is a 70% increase relative to the control strain TWF001. The results suggested that the combined engineering of glyoxylate shunt and L-threonine biosynthesis pathway could significantly increase the L-threonine production in E. coli.
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Affiliation(s)
- Hui Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Yu Fang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China. .,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China.
| | - Lei Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Jianli Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Ye Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China
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Balikó G, Vernyik V, Karcagi I, Györfy Z, Draskovits G, Fehér T, Pósfai G. Rational Efforts to Streamline the Escherichia coliGenome. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Gabriella Balikó
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Viktor Vernyik
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Ildikó Karcagi
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Zsuzsanna Györfy
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Gábor Draskovits
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Tamás Fehér
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - György Pósfai
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
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42
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Xu JZ, Yang HK, Zhang WG. NADPH metabolism: a survey of its theoretical characteristics and manipulation strategies in amino acid biosynthesis. Crit Rev Biotechnol 2018; 38:1061-1076. [PMID: 29480038 DOI: 10.1080/07388551.2018.1437387] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Reduced nicotinamide adenine nucleotide phosphate (NADPH), which is one of the key cofactors in the metabolic network, plays an important role in the biochemical reactions, and physiological function of amino acid-producing strains. The manipulation of NADPH availability and form is an efficient and easy method of redirecting the carbon flux to the amino acid biosynthesis in industrial strains. In this review, we survey the metabolic mode of NADPH. Furthermore, we summarize the research developments in the understanding of the relationship between NADPH metabolism and amino acid biosynthesis. Detailed strategies to manipulate NADPH availability are addressed based on this knowledge. Finally, the uses of NADPH manipulation strategies to enhance the metabolic function of amino acid-producing strains are discussed.
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Affiliation(s)
- Jian-Zhong Xu
- a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , WuXi , PR China.,b The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , WuXi , PR China
| | - Han-Kun Yang
- a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , WuXi , PR China
| | - Wei-Guo Zhang
- a The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , WuXi , PR China
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43
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Diverse genetic error modes constrain large-scale bio-based production. Nat Commun 2018; 9:787. [PMID: 29463788 PMCID: PMC5820350 DOI: 10.1038/s41467-018-03232-w] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/26/2018] [Indexed: 11/18/2022] Open
Abstract
A transition toward sustainable bio-based chemical production is important for green growth. However, productivity and yield frequently decrease as large-scale microbial fermentation progresses, commonly ascribed to phenotypic variation. Yet, given the high metabolic burden and toxicities, evolutionary processes may also constrain bio-based production. We experimentally simulate large-scale fermentation with mevalonic acid-producing Escherichia coli. By tracking growth rate and production, we uncover how populations fully sacrifice production to gain fitness within 70 generations. Using ultra-deep (>1000×) time-lapse sequencing of the pathway populations, we identify multiple recurring intra-pathway genetic error modes. This genetic heterogeneity is only detected using deep-sequencing and new population-level bioinformatics, suggesting that the problem is underestimated. A quantitative model explains the population dynamics based on enrichment of spontaneous mutant cells. We validate our model by tuning production load and escape rate of the production host and apply multiple orthogonal strategies for postponing genetically driven production declines. The declining performance of scale-up bioreactor cultures is commonly attributed to phenotypic and physical heterogeneities. Here, the authors reveal multiple recurring intra-pathway error modes that limit engineered E. coli mevalonic acid production over time- and industrial-scale fermentations.
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44
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Yan P, Wu Y, Yang L, Wang Z, Chen T. Engineering genome-reduced Bacillus subtilis for acetoin production from xylose. Biotechnol Lett 2017; 40:393-398. [PMID: 29236191 DOI: 10.1007/s10529-017-2481-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/13/2017] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To investigate the capacity of a genome-reduced Bacillus subtilis strain as chassis cell for acetoin production from xylose. RESULTS To endow the genome-reduced Bacillus subtilis strain BSK814 with the ability to utilize xylose, we inserted a native xyl operon into its genome and deleted the araR gene. The resulting strain BSK814A2 produced 2.94 g acetoin/l from 10 g xylose/l, which was 39% higher than control strain BSK19A2. The deletion of the bdhA and acoA genes further improved xylose utilization efficiency and increased acetoin production to 3.71 g/l in BSK814A4. Finally, BSK814A4 produced up to 23.3 g acetoin/l from 50 g xylose/l, with a yield of 0.46 g/g xylose. Both the titer and yield were 39% higher than those of control strain BSK19A4. CONCLUSIONS As a chassis cell, genome-reduced B. subtilis showed significantly improved capacity for the production of the overflow product acetoin from xylose compared with wild-type strain.
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Affiliation(s)
- Panpan Yan
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center for Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yuanqing Wu
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center for Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Li Yang
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center for Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.,College of life Science, Shihezi University, Shihezi, 832000, People's Republic of China
| | - Zhiwen Wang
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center for Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Tao Chen
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center for Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
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45
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Lee JH, Wendisch VF. Production of amino acids - Genetic and metabolic engineering approaches. BIORESOURCE TECHNOLOGY 2017; 245:1575-1587. [PMID: 28552565 DOI: 10.1016/j.biortech.2017.05.065] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 05/22/2023]
Abstract
The biotechnological production of amino acids occurs at the million-ton scale and annually about 6milliontons of l-glutamate and l-lysine are produced by Escherichia coli and Corynebacterium glutamicum strains. l-glutamate and l-lysine production from starch hydrolysates and molasses is very efficient and access to alternative carbon sources and new products has been enabled by metabolic engineering. This review focusses on genetic and metabolic engineering of amino acid producing strains. In particular, rational approaches involving modulation of transcriptional regulators, regulons, and attenuators will be discussed. To address current limitations of metabolic engineering, this article gives insights on recent systems metabolic engineering approaches based on functional tools and method such as genome reduction, amino acid sensors based on transcriptional regulators and riboswitches, CRISPR interference, small regulatory RNAs, DNA scaffolding, and optogenetic control, and discusses future prospects.
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Affiliation(s)
- Jin-Ho Lee
- Major in Food Science & Biotechnology, School of Food Biotechnology & Nutrition, Kyungsung University, 309, Suyeong-ro, Nam-gu, Busan 48434, Republic of Korea
| | - Volker F Wendisch
- Genetics of Prokaryotes, Faculty of Biology and Center for Biotechnology, Bielefeld University, Bielefeld, Germany.
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Li Y, Wei H, Wang T, Xu Q, Zhang C, Fan X, Ma Q, Chen N, Xie X. Current status on metabolic engineering for the production of l-aspartate family amino acids and derivatives. BIORESOURCE TECHNOLOGY 2017; 245:1588-1602. [PMID: 28579173 DOI: 10.1016/j.biortech.2017.05.145] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/20/2017] [Accepted: 05/22/2017] [Indexed: 06/07/2023]
Abstract
The l-aspartate amino acids (AFAAs) are constituted of l-aspartate, l-lysine, l-methionine, l-threonine and l-isoleucine. Except for l-aspartate, AFAAs are essential amino acids that cannot be synthesized by humans and most farm animals, and thus possess wide applications in food, animal feed, pharmaceutical and cosmetics industries. To date, a number of amino acids, including AFAAs have been industrially produced by microbial fermentation. However, the overall metabolic and regulatory mechanisms of the synthesis of AFAAs and the recent progress on strain construction have rarely been reviewed. Aiming to promote the establishment of strains of Corynebacterium glutamicum and Escherichia coli, the two industrial amino acids producing bacteria, that are capable of producing high titers of AFAAs and derivatives, this paper systematically summarizes the current progress on metabolic engineering manipulations in both central metabolic pathways and AFAA synthesis pathways based on the category of the five-word strain breeding strategies: enter, flow, moderate, block and exit.
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Affiliation(s)
- Yanjun Li
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Hongbo Wei
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Ting Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Qingyang Xu
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Chenglin Zhang
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xiaoguang Fan
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Qian Ma
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Ning Chen
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xixian Xie
- National and Local United Engineering Lab of Metabolic Control Fermentation Technology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Microbial Engineering of China Light Industry, Tianjin University of Science and Technology, Tianjin 300457, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
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47
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Xu T, Li Y, He Z, Van Nostrand JD, Zhou J. Cas9 Nickase-Assisted RNA Repression Enables Stable and Efficient Manipulation of Essential Metabolic Genes in Clostridium cellulolyticum. Front Microbiol 2017; 8:1744. [PMID: 28936208 PMCID: PMC5594222 DOI: 10.3389/fmicb.2017.01744] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/28/2017] [Indexed: 11/16/2022] Open
Abstract
Essential gene functions remain largely underexplored in bacteria. Clostridium cellulolyticum is a promising candidate for consolidated bioprocessing; however, its genetic manipulation to reduce the formation of less-valuable acetate is technically challenging due to the essentiality of acetate-producing genes. Here we developed a Cas9 nickase-assisted chromosome-based RNA repression to stably manipulate essential genes in C. cellulolyticum. Our plasmid-based expression of antisense RNA (asRNA) molecules targeting the phosphotransacetylase (pta) gene successfully reduced the enzymatic activity by 35% in cellobiose-grown cells, metabolically decreased the acetate titer by 15 and 52% in wildtype transformants on cellulose and xylan, respectively. To control both acetate and lactate simultaneously, we transformed the repression plasmid into lactate production-deficient mutant and found the plasmid delivery reduced acetate titer by more than 33%, concomitant with negligible lactate formation. The strains with pta gene repression generally diverted more carbon into ethanol. However, further testing on chromosomal integrants that were created by double-crossover recombination exhibited only very weak repression because DNA integration dramatically lessened gene dosage. With the design of a tandem repetitive promoter-driven asRNA module and the use of a new Cas9 nickase genome editing tool, a chromosomal integrant (LM3P) was generated in a single step and successfully enhanced RNA repression, with a 27% decrease in acetate titer on cellulose in antibiotic-free medium. These results indicate the effectiveness of tandem promoter-driven RNA repression modules in promoting gene repression in chromosomal integrants. Our combinatorial method using a Cas9 nickase genome editing tool to integrate the gene repression module demonstrates easy-to-use and high-efficiency advantages, paving the way for stably manipulating genes, even essential ones, for functional characterization and microbial engineering.
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Affiliation(s)
- Tao Xu
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Yongchao Li
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Zhili He
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Joy D. Van Nostrand
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, United States
- Earth Sciences Division, Lawrence Berkeley National Laboratory, BerkeleyCA, United States
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua UniversityBeijing, China
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Reuß DR, Commichau FM, Stülke J. The contribution of bacterial genome engineering to sustainable development. Microb Biotechnol 2017; 10:1259-1263. [PMID: 28772004 PMCID: PMC5609340 DOI: 10.1111/1751-7915.12784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/01/2017] [Indexed: 11/30/2022] Open
Abstract
The United Nations’ Sustainable Development Goals define important challenges for the prosperous development of mankind. To reach several of these goals, among them the production of value‐added compounds, improved economic and ecologic balance of production processes, prevention of climate change and protection of ecosystems, the use of engineered bacteria can make valuable contributions. We discuss the strategies for genome engineering and how they can be applied to meet the United Nations’ goals for sustainable development.
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Affiliation(s)
- Daniel R Reuß
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077, Göttingen, Germany
| | - Fabian M Commichau
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077, Göttingen, Germany
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Kadisch M, Willrodt C, Hillen M, Bühler B, Schmid A. Maximizing the stability of metabolic engineering-derived whole-cell biocatalysts. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201600170] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/22/2017] [Accepted: 06/08/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Marvin Kadisch
- Department Solar Materials; Helmholtz Centre for Environmental Research - UFZ; Leipzig Germany
| | - Christian Willrodt
- Department Solar Materials; Helmholtz Centre for Environmental Research - UFZ; Leipzig Germany
| | - Michael Hillen
- Department Solar Materials; Helmholtz Centre for Environmental Research - UFZ; Leipzig Germany
| | - Bruno Bühler
- Department Solar Materials; Helmholtz Centre for Environmental Research - UFZ; Leipzig Germany
| | - Andreas Schmid
- Department Solar Materials; Helmholtz Centre for Environmental Research - UFZ; Leipzig Germany
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50
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Abstract
Genome size is determined during evolution, but it can also be altered by genetic engineering in laboratories. The systematic characterization of reduced genomes provides valuable insights into the cellular properties that are quantitatively described by the global parameters related to the dynamics of growth and mutation. In the present study, we analyzed a small collection of W3110 Escherichia coli derivatives containing either the wild-type genome or reduced genomes of various lengths to examine whether the mutation rate, a global parameter representing genomic plasticity, was affected by genome reduction. We found that the mutation rates of these cells increased with genome reduction. The correlation between genome length and mutation rate, which has been reported for the evolution of bacteria, was also identified, intriguingly, for genome reduction. Gene function enrichment analysis indicated that the deletion of many of the genes encoding membrane and transport proteins play a role in the mutation rate changes mediated by genome reduction. Furthermore, the increase in the mutation rate with genome reduction was highly associated with a decrease in the growth rate in a nutrition-dependent manner; thus, poorer media showed a larger change that was of higher significance. This negative correlation was strongly supported by experimental evidence that the serial transfer of the reduced genome improved the growth rate and reduced the mutation rate to a large extent. Taken together, the global parameters corresponding to the genome, growth, and mutation showed a coordinated relationship, which might be an essential working principle for balancing the cellular dynamics appropriate to the environment. Genome reduction is a powerful approach for investigating the fundamental rules for living systems. Whether genetically disturbed genomes have any specific properties that are different from or similar to those of natively evolved genomes has been under investigation. In the present study, we found that Escherichia coli cells with reduced genomes showed accelerated nucleotide substitution errors (mutation rates), although these cells retained the normal DNA mismatch repair systems. Intriguingly, this finding of correlation between reduced genome size and a higher mutation rate was consistent with the reported evolution of mutation rates. Furthermore, the increased mutation rate was quantitatively associated with a decreased growth rate, indicating that the global parameters related to the genome, growth, and mutation, which represent the amount of genetic information, the efficiency of propagation, and the fidelity of replication, respectively, are dynamically coordinated.
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