1
|
Alobaidallah MSA, García V, Wellner SM, Thomsen LE, Herrero-Fresno A, Olsen JE. Enhancing the Efficacy of Chloramphenicol Therapy for Escherichia coli by Targeting the Secondary Resistome. Antibiotics (Basel) 2024; 13:73. [PMID: 38247632 PMCID: PMC10812820 DOI: 10.3390/antibiotics13010073] [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: 12/13/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
The increasing prevalence of antimicrobial resistance and the limited availability of new antimicrobial agents have created an urgent need for new approaches to combat these issues. One such approach involves reevaluating the use of old antibiotics to ensure their appropriate usage and maximize their effectiveness, as older antibiotics could help alleviate the burden on newer agents. An example of such an antibiotic is chloramphenicol (CHL), which is rarely used due to its hematological toxicity. In the current study, we employed a previously published transposon mutant library in MG1655/pTF2::blaCTX-M-1, containing over 315,000 unique transposon insertions, to identify the genetic factors that play an important role during growth in the presence of CHL. The list of conditionally essential genes, collectively referred to as the secondary resistome (SR), included 67 genes. To validate our findings, we conducted gene knockout experiments on six genes: arcA, hfq, acrZ, cls, mdfA, and nlpI. Deleting these genes resulted in increased susceptibility to CHL as demonstrated by MIC estimations and growth experiments, suggesting that targeting the products encoded from these genes may reduce the dose of CHL needed for treatment and hence reduce the toxicity associated with CHL treatment. Thus, the gene products are indicated as targets for antibiotic adjuvants to favor the use of CHL in modern medicine.
Collapse
Affiliation(s)
- Mosaed Saleh A. Alobaidallah
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (M.S.A.A.); (V.G.); (S.M.W.); (L.E.T.)
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Jeddah 21423, Saudi Arabia
- King Abdullah International Medical Research Center, Jeddah 22384, Saudi Arabia
| | - Vanesa García
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (M.S.A.A.); (V.G.); (S.M.W.); (L.E.T.)
- Laboratorio de Referencia de Escherichia coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade da Santiago de Compostela (USC), 27002 Lugo, Spain
| | - Sandra M. Wellner
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (M.S.A.A.); (V.G.); (S.M.W.); (L.E.T.)
| | - Line E. Thomsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (M.S.A.A.); (V.G.); (S.M.W.); (L.E.T.)
| | - Ana Herrero-Fresno
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (M.S.A.A.); (V.G.); (S.M.W.); (L.E.T.)
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, Campus Terra, Universidade da Santiago de Compostela (USC), 27002 Lugo, Spain
| | - John Elmerdahl Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (M.S.A.A.); (V.G.); (S.M.W.); (L.E.T.)
| |
Collapse
|
2
|
Turner CB, Blount ZD, Mitchell DH, Lenski RE. Evolution of a cross-feeding interaction following a key innovation in a long-term evolution experiment with Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001390. [PMID: 37650867 PMCID: PMC10482366 DOI: 10.1099/mic.0.001390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/15/2023] [Indexed: 09/01/2023]
Abstract
The evolution of a novel trait can profoundly change an organism's effects on its environment, which can in turn affect the further evolution of that organism and any coexisting organisms. We examine these effects and feedbacks following the evolution of a novel function in the Long-Term Evolution Experiment (LTEE) with Escherichia coli. A characteristic feature of E. coli is its inability to grow aerobically on citrate (Cit-). Nonetheless, a Cit+ variant with this capacity evolved in one LTEE population after 31 000 generations. The Cit+ clade then coexisted stably with another clade that retained the ancestral Cit- phenotype. This coexistence was shaped by the evolution of a cross-feeding relationship based on C4-dicarboxylic acids, particularly succinate, fumarate, and malate, that the Cit+ variants release into the medium. Both the Cit- and Cit+ cells evolved to grow on these excreted resources. The evolution of aerobic growth on citrate thus led to a transition from an ecosystem based on a single limiting resource, glucose, to one with at least five resources that were either shared or partitioned between the two coexisting clades. Our findings show that evolutionary novelties can change environmental conditions in ways that facilitate diversity by altering ecosystem structure and the evolutionary trajectories of coexisting lineages.
Collapse
Affiliation(s)
- Caroline B. Turner
- Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI, USA
- Present address: Department of Biology, Loyola University Chicago, Chicago, IL, USA
| | - Zachary D. Blount
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Daniel H. Mitchell
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
- Present address: Biological Sciences, University of New Hampshire, Durham, NH, USA
| | - Richard E. Lenski
- Department of Microbiology and Molecular Genetics; and Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
3
|
Zhang Y, Sun Q, Liu Y, Cen X, Liu D, Chen Z. Development of a plasmid stabilization system in Vibrio natriegens for the high production of 1,3-propanediol and 3-hydroxypropionate. BIORESOUR BIOPROCESS 2021; 8:125. [PMID: 38650249 PMCID: PMC10992974 DOI: 10.1186/s40643-021-00485-0] [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: 10/29/2021] [Accepted: 12/07/2021] [Indexed: 11/10/2022] Open
Abstract
Vibrio natriegens is a promising industrial chassis with a super-fast growth rate and high substrate uptake rates. V. natriegens was previously engineered to produce 1,3-propanediol (1,3-PDO) from glycerol by overexpressing the corresponding genes in a plasmid. However, antibiotic selection pressure for plasmid stability was not satisfactory and plasmid loss resulted in reduced productivity of the bioprocess. In this study, we developed an antibiotic-free plasmid stabilization system for V. natriegens. The system was achieved by shifting the glpD gene, one of the essential genes for glycerol degradation, from the chromosome to plasmid. With this system, engineered V. natriegens can stably maintain a large expression plasmid during the whole fed-batch fermentation and accumulated 69.5 g/L 1,3-PDO in 24 h, which was 23% higher than that based on antibiotic selection system. This system was also applied to engineering V. natriegens for the production of 3-hydroxypropionate (3-HP), enabling the engineered strain to accumulate 64.5 g/L 3-HP in 24 h, which was 30% higher than that based on antibiotic system. Overall, the developed strategy could be useful for engineering V. natriegens as a platform for the production of value-added chemicals from glycerol.
Collapse
Affiliation(s)
- Ye Zhang
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Qing Sun
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Yu Liu
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Xuecong Cen
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Dehua Liu
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
- Tsinghua Innovation Center in Dongguan, Dongguan, 523808, China
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Zhen Chen
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
- Tsinghua Innovation Center in Dongguan, Dongguan, 523808, China.
- Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
4
|
Li X, Bao T, Osire T, Qiao Z, Liu J, Zhang X, Xu M, Yang T, Rao Z. MarR-type transcription factor RosR regulates glutamate metabolism network and promotes accumulation of L-glutamate in Corynebacterium glutamicum G01. BIORESOURCE TECHNOLOGY 2021; 342:125945. [PMID: 34560435 DOI: 10.1016/j.biortech.2021.125945] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Transcription factors (TFs) perform a crucial function in the regulation of amino acids biosynthesis. Here, TFs involved in L-glutamate biosynthesis in Corynebacterium glutamicum were investigated. Compared to transcriptomic results of C. glutamicum 13032, 7 TFs regulated to glutamate biosynthesis were indentifed in G01 and E01. Among them, RosR was demonstrated to regulate L-glutamate metabolic network by binding to the promoters of glnA, pqo, ilvB, ilvN, ilvC, ldhA, odhA, dstr1, fas, argJ, ak and pta. Overexpression of RosR in G01 resulted in significantly decreased by-products yield and improved L-glutamate titer (130.6 g/L) and yield (0.541 g/g from glucose) in fed-batch fermentation. This study demonstrated the L-glutamate production improved by the expression of TFs in C. glutamicum, which provided a good reference for the transcriptional regulation engineering of strains for amino acid biosynthesis and suggested further metabolic engineering of C. glutamicum for L-glutamate production.
Collapse
Affiliation(s)
- Xiangfei Li
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Teng Bao
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Tolbert Osire
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhina Qiao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiafeng Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xian Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Meijuan Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
| |
Collapse
|
5
|
Matson MM, Cepeda MM, Zhang A, Case AE, Kavvas ES, Wang X, Carroll AL, Tagkopoulos I, Atsumi S. Adaptive laboratory evolution for improved tolerance of isobutyl acetate in Escherichia coli. Metab Eng 2021; 69:50-58. [PMID: 34763090 DOI: 10.1016/j.ymben.2021.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 10/14/2021] [Accepted: 11/04/2021] [Indexed: 02/08/2023]
Abstract
Previously, Escherichia coli was engineered to produce isobutyl acetate (IBA). Titers greater than the toxicity threshold (3 g/L) were achieved by using layer-assisted production. To avoid this costly and complex method, adaptive laboratory evolution (ALE) was applied to E. coli for improved IBA tolerance. Over 37 rounds of selective pressure, 22 IBA-tolerant mutants were isolated. Remarkably, these mutants not only tolerate high IBA concentrations, they also produce higher IBA titers. Using whole-genome sequencing followed by CRISPR/Cas9 mediated genome editing, the mutations (SNPs in metH, rho and deletion of arcA) that confer improved tolerance and higher titers were elucidated. The improved IBA titers in the evolved mutants were a result of an increased supply of acetyl-CoA and altered transcriptional machinery. Without the use of phase separation, a strain capable of 3.2-fold greater IBA production than the parent strain was constructed by combing select beneficial mutations. These results highlight the impact improved tolerance has on the production capability of a biosynthetic system.
Collapse
Affiliation(s)
- Morgan M Matson
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Mateo M Cepeda
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Angela Zhang
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Anna E Case
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Erol S Kavvas
- Genome Center, University of California, Davis, CA, 95616, USA
| | - Xiaokang Wang
- Genome Center, University of California, Davis, CA, 95616, USA; Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Austin L Carroll
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Ilias Tagkopoulos
- Genome Center, University of California, Davis, CA, 95616, USA; Department of Computer Science, University of California, Davis, CA, 95616, USA
| | - Shota Atsumi
- Department of Chemistry, University of California, Davis, CA, 95616, USA.
| |
Collapse
|
6
|
Zhang Y, Li Z, Liu Y, Cen X, Liu D, Chen Z. Systems metabolic engineering of Vibrio natriegens for the production of 1,3-propanediol. Metab Eng 2021; 65:52-65. [PMID: 33722653 DOI: 10.1016/j.ymben.2021.03.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/28/2021] [Accepted: 03/06/2021] [Indexed: 11/18/2022]
Abstract
The economic viability of current bio-production systems is often limited by its low productivity due to slow cell growth and low substrate uptake rate. The fastest-growing bacterium Vibrio natriegens is a highly promising next-generation workhorse of the biotechnology industry which can utilize various industrially relevant carbon sources with high substrate uptake rates. Here, we demonstrate the first systematic engineering example of V. natriegens for the heterologous production of 1,3-propanediol (1,3-PDO) from glycerol. Systems metabolic engineering strategies have been applied in this study to develop a superior 1,3-PDO producer, including: (1) heterologous pathway construction and optimization; (2) engineering cellular transcriptional regulators and global transcriptomic analysis; (3) enhancing intracellular reducing power by cofactor engineering; (4) reducing the accumulation of toxic intermediate by pathway engineering; (5) systematic engineering of glycerol oxidation pathway to eliminate byproduct formation. A final engineered strain can efficiently produce 1,3-PDO with a titer of 56.2 g/L, a yield of 0.61 mol/mol, and an average productivity of 2.36 g/L/h. The strategies described in this study would be useful for engineering V. natriegens as a potential chassis for the production of other useful chemicals and biofuels.
Collapse
Affiliation(s)
- Ye Zhang
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Zihua Li
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Yu Liu
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Xuecong Cen
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Dehua Liu
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Tsinghua Innovation Center in Dongguan, Dongguan, 523808, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Zhen Chen
- Key Laboratory of Industrial Biocatalysis (Ministry of Education), Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Tsinghua Innovation Center in Dongguan, Dongguan, 523808, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
7
|
Liao Y, Ni Z, Wu J, Li Z, Ge Y, Chen X, Yao J. Effect of acetate metabolism modulation on 2'-fucosyllactose production in engineered Escherichia coli. BIOTECHNOL BIOTEC EQ 2021. [DOI: 10.1080/13102818.2021.1885996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Yingxue Liao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Scinece Island Branch, Graduate School of USTC, Hefei, PR China
| | - Zhijian Ni
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Scinece Island Branch, Graduate School of USTC, Hefei, PR China
| | - Jinyong Wu
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Huainan New Energy Research Center, Institute of Plasma Physics, Chinese Academy of Sciences, Huainan, Anhui, PR China
| | - Zhongkui Li
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Scinece Island Branch, Graduate School of USTC, Hefei, PR China
| | - Yuanfei Ge
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Scinece Island Branch, Graduate School of USTC, Hefei, PR China
| | - Xiangsong Chen
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Huainan New Energy Research Center, Institute of Plasma Physics, Chinese Academy of Sciences, Huainan, Anhui, PR China
| | - Jianming Yao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China
- Scinece Island Branch, Graduate School of USTC, Hefei, PR China
| |
Collapse
|
8
|
Smirnova GV, Tyulenev AV, Muzyka NG, Oktyabrsky ON. Study of the relationship between extracellular superoxide and glutathione production in batch cultures of Escherichia coli. Res Microbiol 2020; 171:301-310. [PMID: 32721518 DOI: 10.1016/j.resmic.2020.07.004] [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: 05/04/2020] [Revised: 07/07/2020] [Accepted: 07/20/2020] [Indexed: 11/26/2022]
Abstract
Aerobically growing Escherichia coli generates superoxide flux into the periplasm via the oxidation of dihydromenaquinone and simultaneously carries out continuous transmembrane cycling of glutathione (GSH). Here we have shown that, under the conditions of a gradual decrease in dissolved oxygen (dO2), characteristic of batch culture, the global regulatory system ArcB/ArcA can play an important role in the coordinated control of extracellular superoxide and GSH fluxes and their interaction with intracellular antioxidant systems. The lowest superoxide production was observed in the menA and arcB mutants, while the atpA, atpC and atpE mutants generated superoxide 1.3-1.5 times faster than the parent. The share of exported glutathione in the ubiC, atpA, atpC, and atpE mutants was 2-3 times higher compared to the parent. A high direct correlation (r = 0.87, p = 0.01) between extracellular superoxide and GSH was revealed. The menA and arcB mutants, as well as the cydD mutant lacking the GSH export system CydDC, were not capable of GSH excretion with a decrease in dO2, which indicates a positive control of GSH export by ArcB. In contrast, ArcB downregulates sodA, therefore, an inverse correlation (r = -0.86, p = 0.013) between superoxide production and sodA expression was observed.
Collapse
Affiliation(s)
- Galina V Smirnova
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| | - Aleksey V Tyulenev
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| | - Nadezda G Muzyka
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| | - Oleg N Oktyabrsky
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, ul. Goleva 13, Perm, 614081, Russia.
| |
Collapse
|
9
|
Liu M, Fu Y, Gao W, Xian M, Zhao G. Highly Efficient Biosynthesis of Hypoxanthine in Escherichia coli and Transcriptome-Based Analysis of the Purine Metabolism. ACS Synth Biol 2020; 9:525-535. [PMID: 32049513 DOI: 10.1021/acssynbio.9b00396] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nucleosides and purine analogues have multiple functions in cell physiology, food additives, and pharmaceuticals, and some are produced on a large scale using different microorganisms. However, biosynthesis of purines is still lacking. In the present study, we engineered the de novo purine biosynthesis pathway, branched pathways, and a global regulator to ensure highly efficient hypoxanthine production by Escherichia coli. The engineered strain Q2973 produced 1243 mg/L hypoxanthine in fed-batch fermentation, accompanied by an extremely low accumulation of byproducts such as acetate and xanthine. We also performed global gene expression analysis to illustrate the mechanism for improving hypoxanthine production. This study demonstrated the feasibility of large-scale hypoxanthine production byan engineered E. coli strain, and provides a reference for subsequent studies on purine analogues and nucleosides.
Collapse
Affiliation(s)
- Min Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China
| | - Yingxin Fu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China
| | - Wenjie Gao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China
| | - Guang Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Siences, Qingdao, 266101, China
| |
Collapse
|
10
|
Suppression of antibiotic resistance evolution by single-gene deletion. Sci Rep 2020; 10:4178. [PMID: 32144279 PMCID: PMC7060189 DOI: 10.1038/s41598-020-60663-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 02/12/2020] [Indexed: 11/08/2022] Open
Abstract
Antibiotic treatment generally results in the selection of resistant bacterial strains, and the dynamics of resistance evolution is dependent on complex interactions between cellular components. To better characterize the mechanisms of antibiotic resistance and evaluate its dependence on gene regulatory networks, we performed systematic laboratory evolution of Escherichia coli strains with single-gene deletions of 173 transcription factors under three different antibiotics. This resulted in the identification of several genes whose deletion significantly suppressed resistance evolution, including arcA and gutM. Analysis of double-gene deletion strains suggested that the suppression of resistance evolution caused by arcA and gutM deletion was not caused by epistatic interactions with mutations known to confer drug resistance. These results provide a methodological basis for combinatorial drug treatments that may help to suppress the emergence of resistant pathogens by inhibiting resistance evolution.
Collapse
|
11
|
Shimizu K, Matsuoka Y. Redox rebalance against genetic perturbations and modulation of central carbon metabolism by the oxidative stress regulation. Biotechnol Adv 2019; 37:107441. [PMID: 31472206 DOI: 10.1016/j.biotechadv.2019.107441] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/04/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022]
Abstract
The micro-aerophilic organisms and aerobes as well as yeast and higher organisms have evolved to gain energy through respiration (via oxidative phosphorylation), thereby enabling them to grow much faster than anaerobes. However, during respiration, reactive oxygen species (ROSs) are inherently (inevitably) generated, and threaten the cell's survival. Therefore, living organisms (or cells) must furnish the potent defense systems to keep such ROSs at harmless level, where the cofactor balance plays crucial roles. Namely, NADH is the source of energy generation (catabolism) in the respiratory chain reactions, through which ROSs are generated, while NADPH plays important roles not only for the cell synthesis (anabolism) but also for detoxifying ROSs. Therefore, the cell must rebalance the redox ratio by modulating the fluxes of the central carbon metabolism (CCM) by regulating the multi-level regulation machinery upon genetic perturbations and the change in the growth conditions. Here, we discuss about how aerobes accomplish such cofactor homeostasis against redox perturbations. In particular, we consider how single-gene mutants (including pgi, pfk, zwf, gnd and pyk mutants) modulate their metabolisms in relation to cofactor rebalance (and also by adaptive laboratory evolution). We also discuss about how the overproduction of NADPH (by the pathway gene mutation) can be utilized for the efficient production of useful value-added chemicals such as medicinal compounds, polyhydroxyalkanoates, and amino acids, all of which require NADPH in their synthetic pathways. We then discuss about the metabolic responses against oxidative stress, where αketoacids play important roles not only for the coordination between catabolism and anabolism, but also for detoxifying ROSs by non-enzymatic reactions, as well as for reducing the production of ROSs by repressing the activities of the TCA cycle and respiration (via carbon catabolite repression). Thus, we discuss about the mechanisms (basic strategies) that modulate the metabolism from respiration to respiro-fermentative metabolism causing overflow, based on the role of Pyk activity, affecting the NADPH production at the oxidative pentose phosphate (PP) pathway, and the roles of αketoacids for the change in the source of energy generation from the oxidative phosphorylation to the substrate level phosphorylation.
Collapse
Affiliation(s)
- Kazuyuki Shimizu
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Institute of Advanced Biosciences, Keio university, Tsuruoka, Yamagata 997-0017, Japan.
| | - Yu Matsuoka
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan.
| |
Collapse
|
12
|
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: 12] [Impact Index Per Article: 2.4] [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.
Collapse
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
| |
Collapse
|
13
|
Wang Y, Xian M, Feng X, Liu M, Zhao G. Biosynthesis of ethylene glycol from d-xylose in recombinant Escherichia coli. Bioengineered 2019; 9:233-241. [PMID: 29865993 PMCID: PMC6984763 DOI: 10.1080/21655979.2018.1478489] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Ethylene glycol (EG) is an important chemical used as antifreeze and a raw material in polyester synthesis. The EG biosynthetic pathway from D-xylose with D-xylonate as key intermediate has some advantages, but showed low EG production. Here, we reconstructed and optimized this pathway in Escherichia coli. In view of the greater intracellular prevalence of NADH, an aldehyde reductase FucO using NADH was employed to convert glycoaldehyde into EG, in replacement of NADPH-dependent reductase YqhD. To suppress the accumulation of by-products acetate and glycolate, two genes arcA and aldA were knocked out. The resultant strain Q2843 produced 72 g/L EG under fed-batch fermentation conditions, with the yield of 0.40 g/g D-xylose and EG productivity of 1.38 g/L/h. The use of NADH-dependent enzyme FucO and by-product elimination significantly improved the performance of EG producing strain, which represented the highest titer, yield and productivity of EG reported so far.
Collapse
Affiliation(s)
- Yuhui Wang
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,b School of Life Science , Shandong University , Jinan , China
| | - Mo Xian
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China
| | - Xinjun Feng
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,c Shandong Provincial Key Laboratory of Synthetic Biology , Qingdao , China
| | - Min Liu
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,c Shandong Provincial Key Laboratory of Synthetic Biology , Qingdao , China
| | - Guang Zhao
- a CAS Key Laboratory of Biobased Materials , Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao , China.,c Shandong Provincial Key Laboratory of Synthetic Biology , Qingdao , China
| |
Collapse
|
14
|
Shimizu K, Matsuoka Y. Regulation of glycolytic flux and overflow metabolism depending on the source of energy generation for energy demand. Biotechnol Adv 2018; 37:284-305. [PMID: 30576718 DOI: 10.1016/j.biotechadv.2018.12.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 11/06/2018] [Accepted: 12/15/2018] [Indexed: 12/11/2022]
Abstract
Overflow metabolism is a common phenomenon observed at higher glycolytic flux in many bacteria, yeast (known as Crabtree effect), and mammalian cells including cancer cells (known as Warburg effect). This phenomenon has recently been characterized as the trade-offs between protein costs and enzyme efficiencies based on coarse-graining approaches. Moreover, it has been recognized that the glycolytic flux increases as the source of energy generation changes from energetically efficient respiration to inefficient respiro-fermentative or fermentative metabolism causing overflow metabolism. It is highly desired to clarify the metabolic regulation mechanisms behind such phenomena. Metabolic fluxes are located on top of the hierarchical regulation systems, and represent the outcome of the integrated response of all levels of cellular regulation systems. In the present article, we discuss about the different levels of regulation systems for the modulation of fluxes depending on the growth rate, growth condition such as oxygen limitation that alters the metabolism towards fermentation, and genetic perturbation affecting the source of energy generation from respiration to respiro-fermentative metabolism in relation to overflow metabolism. The intracellular metabolite of the upper glycolysis such as fructose 1,6-bisphosphate (FBP) plays an important role not only for flux sensing, but also for the regulation of the respiratory activity either directly or indirectly (via transcription factors) at higher growth rate. The glycolytic flux regulation is backed up (enhanced) by unphosphorylated EIIA and HPr of the phosphotransferase system (PTS) components, together with the sugar-phosphate stress regulation, where the transcriptional regulation is further modulated by post-transcriptional regulation via the degradation of mRNA (stability of mRNA) in Escherichia coli. Moreover, the channeling may also play some role in modulating the glycolytic cascade reactions.
Collapse
Affiliation(s)
- Kazuyuki Shimizu
- Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan.
| | - Yu Matsuoka
- Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan
| |
Collapse
|
15
|
Microbial Cell Factories à la Carte: Elimination of Global Regulators Cra and ArcA Generates Metabolic Backgrounds Suitable for the Synthesis of Bioproducts in Escherichia coli. Appl Environ Microbiol 2018; 84:AEM.01337-18. [PMID: 30030227 DOI: 10.1128/aem.01337-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/16/2018] [Indexed: 11/20/2022] Open
Abstract
Manipulation of global regulators is one of the strategies used for the construction of bacterial strains suitable for the synthesis of bioproducts. However, the pleiotropic effects of these regulators can vary under different conditions and are often strain dependent. This study analyzed the effects of ArcA, CreC, Cra, and Rob using single deletion mutants of the well-characterized and completely sequenced Escherichia coli strain BW25113. Comparison of the effects of each regulator on the synthesis of major extracellular metabolites, tolerance to several compounds, and synthesis of native and nonnative bioproducts under different growth conditions allowed the discrimination of the particular phenotypes that can be attributed to the individual mutants and singled out Cra and ArcA as the regulators with the most important effects on bacterial metabolism. These data were used to identify the most suitable backgrounds for the synthesis of the reduced bioproducts succinate and 1,3-propanediol (1,3-PDO). The Δcra mutant was further modified to enhance succinate synthesis by the addition of enzymes that increase NADH and CO2 availability, achieving an 80% increase compared to the parental strain. Production of 1,3-PDO in the ΔarcA mutant was optimized by overexpression of PhaP, which increased more than twice the amount of the diol compared to the wild type in a semidefined medium using glycerol, resulting in 24 g · liter-1 of 1,3-PDO after 48 h, with a volumetric productivity of 0.5 g · liter-1 h-1 IMPORTANCE Although the effects of many global regulators, especially ArcA and Cra, have been studied in Escherichia coli, the metabolic changes caused by the absence of global regulators have been observed to differ between strains. This scenario complicates the identification of the individual effects of the regulators, which is essential for the design of metabolic engineering strategies. The genome of Escherichia coli BW25113 has been completely sequenced and does not contain additional mutations that could mask or interfere with the effects of the global regulator mutations. The uniform genetic background of the Keio collection mutants enabled the characterization of the physiological consequences of altered carbon and redox fluxes caused by each global regulator deletion, eliminating possible strain-dependent results. As a proof of concept, Δcra and ΔarcA mutants were subjected to further manipulations to obtain large amounts of succinate and 1,3-PDO, demonstrating that the metabolic backgrounds of the mutants were suitable for the synthesis of bioproducts.
Collapse
|
16
|
Golubeva LI, Shupletsov MS, Mashko SV. Metabolic Flux Analysis using 13C Isotopes: III. Significance for Systems Biology and Metabolic Engineering. APPL BIOCHEM MICRO+ 2018. [DOI: 10.1134/s0003683817090058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
17
|
Liu M, Ding Y, Chen H, Zhao Z, Liu H, Xian M, Zhao G. Improving the production of acetyl-CoA-derived chemicals in Escherichia coli BL21(DE3) through iclR and arcA deletion. BMC Microbiol 2017; 17:10. [PMID: 28061812 PMCID: PMC5219675 DOI: 10.1186/s12866-016-0913-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 12/13/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Acetyl-CoA-derived chemicals are suitable for multiple applications in many industries. The bio-production of these chemicals has become imperative owing to the economic and environmental problems. However, acetate overflow is the major drawback for acetyl-CoA-derived chemicals production. Approaches for overcoming acetate overflow may be beneficial for the production of acetyl-CoA-derived chemicals. RESULTS In this study, a transcriptional regulator iclR was knocked out in E.coli BL21(DE3) to overcome acetate overflow and improve the chemicals production. Two important acetyl-CoA-derived chemicals, phloroglucinol (PG) and 3-hydroxypropionate (3HP) were used to evaluate it. It is revealed that knockout of iclR significantly increased expressions of aceBAK operon. The cell yields and glucose utilization efficiencies were higher than those of control strains. The acetate concentrations were decreased by more than 50% and the productions of PG and 3HP were increased more than twice in iclR mutants. The effects of iclR knockout on cell physiology, cell metabolism and production of acetyl-CoA-derived chemicals were similar to those of arcA knockout in our previous study. However, the arcA-iclR double mutants couldn't gain higher productions of PG and 3HP. The mechanisms are unclear and needed to be resolved in future. CONCLUSIONS Knockout of iclR significantly increased gene expression of aceBAK operon and concomitantly activated glyoxylate pathway. This genetic modification may be a good way to overcome acetate overflow, and improve the production of a wide range of acetyl-CoA-derived chemicals.
Collapse
Affiliation(s)
- Min Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Yamei Ding
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Hailin Chen
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhe Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huizhou Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
| | - Guang Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China. .,Randian Technology Company Limited, Tianjin, 300457, China.
| |
Collapse
|
18
|
Pablos TE, Olivares R, Sigala JC, Ramírez OT, Lara AR. Toward efficient microaerobic processes using engineeredEscherichia coliW3110 strains. Eng Life Sci 2016. [DOI: 10.1002/elsc.201500129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Tania E. Pablos
- Doctorado en Ciencias Biológicas y de la Salud; Universidad Autónoma Metropolitana; México D.F. México
| | - Roberto Olivares
- Departamento de Procesos y Tecnología; Universidad Autónoma Metropolitana-Cuajimalpa; México D.F. México
| | - Juan Carlos Sigala
- Departamento de Procesos y Tecnología; Universidad Autónoma Metropolitana-Cuajimalpa; México D.F. México
| | - Octavio T. Ramírez
- Departamento de Medicina Molecular y Bioprocesos; Instituto de Biotecnología; Universidad Nacional Autónoma de México; Cuernavaca México
| | - Alvaro R. Lara
- Departamento de Procesos y Tecnología; Universidad Autónoma Metropolitana-Cuajimalpa; México D.F. México
| |
Collapse
|
19
|
Liu M, Feng X, Ding Y, Zhao G, Liu H, Xian M. Metabolic engineering of Escherichia coli to improve recombinant protein production. Appl Microbiol Biotechnol 2015; 99:10367-77. [DOI: 10.1007/s00253-015-6955-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/18/2015] [Accepted: 08/22/2015] [Indexed: 01/13/2023]
|
20
|
Liu M, Yao L, Xian M, Ding Y, Liu H, Zhao G. Deletion of arcA increased the production of acetyl-CoA-derived chemicals in recombinant Escherichia coli. Biotechnol Lett 2015; 38:97-101. [PMID: 26362674 DOI: 10.1007/s10529-015-1953-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/01/2015] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Acetyl-CoA is used to produce many valuable metabolites in Escherichia coli. However, acetate overflow is a major shortcoming. Knockout of the global regulator gene, arcA, may solve this problem. RESULTS The arcA gene of E. coli BL21(DE3) was knocked out, and the production of phloroglucinol (PG) and 3-hydroxypropionate (3HP), both derived from acetyl-CoA, were used to evaluate its effect. The arcA mutants had higher cell yields and higher glucose utilization efficiencies than the corresponding control strains, and the productions of PG and 3HP were 0.92 g/l and 0.27 g/l, respectively; more than twice that of the control strains. Furthermore, arcA knockout also showed significant repression on formation of acetate, the major byproduct in fermentation. Acetate concentrations were decreased 69.4 % and 87 % by arcA knockout during the production of PG and 3HP, respectively. CONCLUSIONS The arcA gene knockout is a solution to acetate overflow and may improve production of a wide range of acetyl-CoA-derived metabolites.
Collapse
Affiliation(s)
- Min Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lan Yao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Yamei Ding
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Huizhou Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
| | - Gao Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
| |
Collapse
|
21
|
Matsuoka Y, Shimizu K. Current status and future perspectives of kinetic modeling for the cell metabolism with incorporation of the metabolic regulation mechanism. BIORESOUR BIOPROCESS 2015. [DOI: 10.1186/s40643-014-0031-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
22
|
Shimizu K. Metabolic Regulation and Coordination of the Metabolism in Bacteria in Response to a Variety of Growth Conditions. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 155:1-54. [PMID: 25712586 DOI: 10.1007/10_2015_320] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Living organisms have sophisticated but well-organized regulation system. It is important to understand the metabolic regulation mechanisms in relation to growth environment for the efficient design of cell factories for biofuels and biochemicals production. Here, an overview is given for carbon catabolite regulation, nitrogen regulation, ion, sulfur, and phosphate regulations, stringent response under nutrient starvation as well as oxidative stress regulation, redox state regulation, acid-shock, heat- and cold-shock regulations, solvent stress regulation, osmoregulation, and biofilm formation, and quorum sensing focusing on Escherichia coli metabolism and others. The coordinated regulation mechanisms are of particular interest in getting insight into the principle which governs the cell metabolism. The metabolism is controlled by both enzyme-level regulation and transcriptional regulation via transcription factors such as cAMP-Crp, Cra, Csr, Fis, P(II)(GlnB), NtrBC, CysB, PhoR/B, SoxR/S, Fur, MarR, ArcA/B, Fnr, NarX/L, RpoS, and (p)ppGpp for stringent response, where the timescales for enzyme-level and gene-level regulations are different. Moreover, multiple regulations are coordinated by the intracellular metabolites, where fructose 1,6-bisphosphate (FBP), phosphoenolpyruvate (PEP), and acetyl-CoA (AcCoA) play important roles for enzyme-level regulation as well as transcriptional control, while α-ketoacids such as α-ketoglutaric acid (αKG), pyruvate (PYR), and oxaloacetate (OAA) play important roles for the coordinated regulation between carbon source uptake rate and other nutrient uptake rate such as nitrogen or sulfur uptake rate by modulation of cAMP via Cya.
Collapse
Affiliation(s)
- Kazuyuki Shimizu
- Kyushu Institute of Technology, Iizuka, Fukuoka, 820-8502, Japan. .,Institute of Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan.
| |
Collapse
|
23
|
Li N, Zhang B, Wang Z, Tang YJ, Chen T, Zhao X. Engineering Escherichia coli for fumaric acid production from glycerol. BIORESOURCE TECHNOLOGY 2014; 174:81-7. [PMID: 25463785 DOI: 10.1016/j.biortech.2014.09.147] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 05/28/2023]
Abstract
The evolved mutant Escherichia coli E2 previously developed for succinate production from glycerol was engineered in this study for fumaric acid production under aerobic conditions. Through deletion of three fumarases, 3.65g/L fumaric acid was produced with the yield of 0.25mol/mol glycerol and a large amount of acetate was accumulated as the main byproduct. In order to reduce acetate production several strategies were attempted, among which increasing the flux of the anaplerotic pathways through overexpression of phosphoenolpyruvate carboxylase gene ppc or the glyoxylate shunt operon aceBA effectively reduced acetate and improved fumaric acid production. In fed-batch culture, the resulting strain EF02(pSCppc) produced 41.5g/L fumaric acid from glycerol with 70% of the maximum theoretical yield and an overall productivity of 0.51g/L/h.
Collapse
Affiliation(s)
- Ning Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Bo Zhang
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Zhiwen Wang
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Ya-Jie Tang
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, PR China
| | - Tao Chen
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
| | - Xueming Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| |
Collapse
|
24
|
Long CP, Antoniewicz MR. Metabolic flux analysis of Escherichia coli knockouts: lessons from the Keio collection and future outlook. Curr Opin Biotechnol 2014; 28:127-33. [PMID: 24686285 DOI: 10.1016/j.copbio.2014.02.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 02/07/2014] [Accepted: 02/10/2014] [Indexed: 12/11/2022]
Abstract
Cellular metabolic and regulatory systems are of fundamental interest to biologists and engineers. Incomplete understanding of these complex systems remains an obstacle to progress in biotechnology and metabolic engineering. An established method for obtaining new information on network structure, regulation and dynamics is to study the cellular system following a perturbation such as a genetic knockout. The Keio collection of all viable Escherichia coli single-gene knockouts is facilitating a systematic investigation of the regulation and metabolism of E. coli. Of all omics measurements available, the metabolic flux profile (the fluxome) provides the most direct and relevant representation of the cellular phenotype. Recent advances in (13)C-metabolic flux analysis are now permitting highly precise and accurate flux measurements for investigating cellular systems and guiding metabolic engineering efforts.
Collapse
Affiliation(s)
- Christopher P Long
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE 19716, USA.
| |
Collapse
|
25
|
Song CW, Kim DI, Choi S, Jang JW, Lee SY. Metabolic engineering ofEscherichia colifor the production of fumaric acid. Biotechnol Bioeng 2013; 110:2025-34. [DOI: 10.1002/bit.24868] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/06/2013] [Accepted: 02/07/2013] [Indexed: 12/20/2022]
|
26
|
Shimizu K. Metabolic Regulation of a Bacterial Cell System with Emphasis on Escherichia coli Metabolism. ISRN BIOCHEMISTRY 2013; 2013:645983. [PMID: 25937963 PMCID: PMC4393010 DOI: 10.1155/2013/645983] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/25/2012] [Indexed: 12/19/2022]
Abstract
It is quite important to understand the overall metabolic regulation mechanism of bacterial cells such as Escherichia coli from both science (such as biochemistry) and engineering (such as metabolic engineering) points of view. Here, an attempt was made to clarify the overall metabolic regulation mechanism by focusing on the roles of global regulators which detect the culture or growth condition and manipulate a set of metabolic pathways by modulating the related gene expressions. For this, it was considered how the cell responds to a variety of culture environments such as carbon (catabolite regulation), nitrogen, and phosphate limitations, as well as the effects of oxygen level, pH (acid shock), temperature (heat shock), and nutrient starvation.
Collapse
Affiliation(s)
- Kazuyuki Shimizu
- Kyushu Institute of Technology, Fukuoka, Iizuka 820-8502, Japan
- Institute of Advanced Bioscience, Keio University, Yamagata, Tsuruoka 997-0017, Japan
| |
Collapse
|
27
|
Toya Y, Nakahigashi K, Tomita M, Shimizu K. Metabolic regulation analysis of wild-type and arcA mutant Escherichia coli under nitrate conditions using different levels of omics data. MOLECULAR BIOSYSTEMS 2013; 8:2593-604. [PMID: 22790675 DOI: 10.1039/c2mb25069a] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is of practical interest to investigate the effect of nitrates on bacterial metabolic regulation of both fermentation and energy generation, as compared to aerobic and anaerobic growth without nitrates. Although gene level regulation has previously been studied for nitrate assimilation, it is important to understand this metabolic regulation in terms of global regulators. In the present study, therefore, we measured gene expression using DNA microarrays, intracellular metabolite concentrations using CE-TOFMS, and metabolic fluxes using the (13)C-labeling technique for wild-type E. coli and the ΔarcA (a global regulatory gene for anoxic response control, ArcA) mutant to compare the metabolic state under nitrate conditions to that under aerobic and anaerobic conditions without nitrates in continuous culture conditions at a dilution rate of 0.2 h(-1). In wild-type, although the measured metabolite concentrations changed very little among the three culture conditions, the TCA cycle and the pentose phosphate pathway fluxes were significantly different under each condition. These results suggested that the ATP production rate was 29% higher under nitrate conditions than that under anaerobic conditions, whereas the ATP production rate was 10% lower than that under aerobic conditions. The flux changes in the TCA cycle were caused by changes in control at the gene expression level. In ΔarcA mutant, the TCA cycle flux was significantly increased (4.4 times higher than that of the wild type) under nitrate conditions. Similarly, the intracellular ATP/ADP ratio increased approximately two-fold compared to that of the wild-type strain.
Collapse
Affiliation(s)
- Yoshihiro Toya
- Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0017, Japan.
| | | | | | | |
Collapse
|
28
|
Winter G, Krömer JO. Fluxomics - connecting ‘omics analysis and phenotypes. Environ Microbiol 2013; 15:1901-16. [DOI: 10.1111/1462-2920.12064] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Revised: 11/21/2012] [Accepted: 11/26/2012] [Indexed: 12/31/2022]
Affiliation(s)
- Gal Winter
- Centre for Microbial Electrosynthesis (CEMES); Advanced Water Management Centre (AWMC); University of Queensland; Brisbane; Qld; Australia
| | - Jens O. Krömer
- Centre for Microbial Electrosynthesis (CEMES); Advanced Water Management Centre (AWMC); University of Queensland; Brisbane; Qld; Australia
| |
Collapse
|
29
|
Manipulation of the anoxic metabolism in Escherichia coli by ArcB deletion variants in the ArcBA two-component system. Appl Environ Microbiol 2012; 78:8784-94. [PMID: 23064346 DOI: 10.1128/aem.02558-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bioprocesses conducted under conditions with restricted O(2) supply are increasingly exploited for the synthesis of reduced biochemicals using different biocatalysts. The model facultative anaerobe Escherichia coli has elaborate sensing and signal transduction mechanisms for redox control in response to the availability of O(2) and other electron acceptors. The ArcBA two-component system consists of ArcB, a membrane-associated sensor kinase, and ArcA, the cognate response regulator. The tripartite hybrid kinase ArcB possesses a transmembrane, a PAS, a primary transmitter (H1), a receiver (D1), and a phosphotransfer (H2) domain. Metabolic fluxes were compared under anoxic conditions in a wild-type E. coli strain, its ΔarcB derivative, and two partial arcB deletion mutants in which ArcB lacked either the H1 domain or the PAS-H1-D1 domains. These analyses revealed that elimination of different segments in ArcB determines a distinctive distribution of d-glucose catabolic fluxes, different from that observed in the ΔarcB background. Metabolite profiles, enzyme activity levels, and gene expression patterns were also investigated in these strains. Relevant alterations were observed at the P-enol-pyruvate/pyruvate and acetyl coenzyme A metabolic nodes, and the formation of reduced fermentation metabolites, such as succinate, d-lactate, and ethanol, was favored in the mutant strains to different extents compared to the wild-type strain. These phenotypic traits were associated with altered levels of the enzymatic activities operating at these nodes, as well as with elevated NADH/NAD(+) ratios. Thus, targeted modification of global regulators to obtain different metabolic flux distributions under anoxic conditions is emerging as an attractive tool for metabolic engineering purposes.
Collapse
|
30
|
Genomic analysis of a key innovation in an experimental Escherichia coli population. Nature 2012; 489:513-8. [PMID: 22992527 PMCID: PMC3461117 DOI: 10.1038/nature11514] [Citation(s) in RCA: 384] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/22/2012] [Indexed: 01/21/2023]
Abstract
Evolutionary novelties have been important in the history of life, but their origins are usually difficult to examine in detail. We previously described the evolution of a novel trait, aerobic citrate utilization (Cit+), in an experimental population of Escherichia coli. Here we analyze genome sequences to investigate the history and genetic basis of this trait. At least three distinct clades coexisted for more than 10,000 generations prior to its emergence. The Cit+ trait originated in one clade by a tandem duplication that captured an aerobically-expressed promoter for the expression of a previously silent citrate transporter. The clades varied in their propensity to evolve this novel trait, although genotypes able to do so existed in all three clades, implying that multiple potentiating mutations arose during the population’s history. Our findings illustrate the importance of promoter capture and altered gene regulation in mediating the exaptation events that often underlie evolutionary innovations.
Collapse
|
31
|
Kuhn D, Fritzsch FSO, Zhang X, Wendisch VF, Blank LM, Bühler B, Schmid A. Subtoxic product levels limit the epoxidation capacity of recombinant E. coli by increasing microbial energy demands. J Biotechnol 2012; 163:194-203. [PMID: 22922011 DOI: 10.1016/j.jbiotec.2012.07.194] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 07/12/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
The utilization of the cellular metabolism for cofactor regeneration is a common motivation for the application of whole cells in redox biocatalysis. Introduction of an active oxidoreductase into a microorganism has profound consequences on metabolism, potentially affecting metabolic and biotransformation efficiency. An ambitious goal of systems biotechnology is to design process-relevant and knowledge-based engineering strategies to improve biocatalyst performance. Metabolic flux analysis (MFA) has shown that the competition for NAD(P)H between redox biocatalysis and the energy metabolism becomes critical during asymmetric styrene epoxidation catalyzed by growing Escherichia coli containing recombinant styrene monooxygenase. Engineering TCA-cycle regulation allowed increased TCA-cycle activities, a delay of acetate formation, and enhanced NAD(P)H yields during batch cultivation. However, at low biomass and product concentrations, the cellular metabolism of both the mutants as well as the native host strains could cope with increased NADH demands during continuous two-liquid phase biotransformations, whereas elevated but still subtoxic product concentrations were found to cause a significantly increased NAD(P)H demand and a compromised efficiency of metabolic operation. In conclusion, operational conditions determine cellular energy and NAD(P)H demands and thus the biocatalytic efficiency of whole-cell redox biocatalysts.
Collapse
Affiliation(s)
- Daniel Kuhn
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 66, D-44227 Dortmund, Germany
| | | | | | | | | | | | | |
Collapse
|
32
|
Liu J, Yong YC, Song H, Li CM. Activation Enhancement of Citric Acid Cycle to Promote Bioelectrocatalytic Activity of arcA Knockout Escherichia coli Toward High-Performance Microbial Fuel Cell. ACS Catal 2012. [DOI: 10.1021/cs3003808] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Jing Liu
- School of Chemical and Biomedical Engineering & Centre for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Yang-Chun Yong
- School of Chemical and Biomedical Engineering & Centre for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
- Biofuels Institute, School of
the Environment, Jiangsu University, 301
Xuefu Road, Zhenjiang 212013, Jiangsu Province, People's Republic
of China
| | - Hao Song
- School of Chemical and Biomedical Engineering & Centre for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
- Singapore
Centre on Environmental
Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, SBS-01n-27, Singapore
637551
| | - Chang Ming Li
- School of Chemical and Biomedical Engineering & Centre for Advanced Bionanosystems, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
- Institute for Clean Energy & Advanced Materials, Southwest University, Chongqing 400715, People's Republic of China
- Chongqing Key Laboratory for Advance Materials and Technologies of Clean Energies, Chongqing 400715, People's Republic of China
| |
Collapse
|
33
|
Mori E, Furusawa C, Kajihata S, Shirai T, Shimizu H. Evaluating 13C enrichment data of free amino acids for precise metabolic flux analysis. Biotechnol J 2011; 6:1377-87. [DOI: 10.1002/biot.201000446] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
34
|
Waegeman H, Beauprez J, Moens H, Maertens J, De Mey M, Foulquié-Moreno MR, Heijnen JJ, Charlier D, Soetaert W. Effect of iclR and arcA knockouts on biomass formation and metabolic fluxes in Escherichia coli K12 and its implications on understanding the metabolism of Escherichia coli BL21 (DE3). BMC Microbiol 2011; 11:70. [PMID: 21481254 PMCID: PMC3094197 DOI: 10.1186/1471-2180-11-70] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 04/11/2011] [Indexed: 11/10/2022] Open
Abstract
Background Gene expression is regulated through a complex interplay of different transcription factors (TFs) which can enhance or inhibit gene transcription. ArcA is a global regulator that regulates genes involved in different metabolic pathways, while IclR as a local regulator, controls the transcription of the glyoxylate pathway genes of the aceBAK operon. This study investigates the physiological and metabolic consequences of arcA and iclR deletions on E. coli K12 MG1655 under glucose abundant and limiting conditions and compares the results with the metabolic characteristics of E. coli BL21 (DE3). Results The deletion of arcA and iclR results in an increase in the biomass yield both under glucose abundant and limiting conditions, approaching the maximum theoretical yield of 0.65 c-mole/c-mole glucose under glucose abundant conditions. This can be explained by the lower flux through several CO2 producing pathways in the E. coli K12 ΔarcAΔiclR double knockout strain. Due to iclR gene deletion, the glyoxylate pathway is activated resulting in a redirection of 30% of the isocitrate molecules directly to succinate and malate without CO2 production. Furthermore, a higher flux at the entrance of the TCA was noticed due to arcA gene deletion, resulting in a reduced production of acetate and less carbon loss. Under glucose limiting conditions the flux through the glyoxylate pathway is further increased in the ΔiclR knockout strain, but this effect was not observed in the double knockout strain. Also a striking correlation between the glyoxylate flux data and the isocitrate lyase activity was observed for almost all strains and under both growth conditions, illustrating the transcriptional control of this pathway. Finally, similar central metabolic fluxes were observed in E. coli K12 ΔarcA ΔiclR compared to the industrially relevant E. coli BL21 (DE3), especially with respect to the pentose pathway, the glyoxylate pathway, and the TCA fluxes. In addition, a comparison of the genome sequences of the two strains showed that BL21 possesses two mutations in the promoter region of iclR and rare codons are present in arcA implying a lower tRNA acceptance. Both phenomena presumably result in a reduced ArcA and IclR synthesis in BL21, which contributes to the similar physiology as observed in E. coli K12 ΔarcAΔiclR. Conclusions The deletion of arcA results in a decrease of repression on transcription of TCA cycle genes under glucose abundant conditions, without significantly affecting the glyoxylate pathway activity. IclR clearly represses transcription of glyoxylate pathway genes under glucose abundance, a condition in which Crp activation is absent. Under glucose limitation, Crp is responsible for the high glyoxylate flux, but IclR still represses transcription. Finally, in E. coli BL21 (DE3), ArcA and IclR are poorly expressed, explaining the similar fluxes observed compared to the ΔarcAΔiclR strain.
Collapse
Affiliation(s)
- Hendrik Waegeman
- Centre of Expertise-Industrial Biotechnology and Biocatalysis, Department of Biochemical and Microbial Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Metabolic regulation in Escherichia coli in response to culture environments via global regulators. Biotechnol J 2011; 6:1330-41. [DOI: 10.1002/biot.201000447] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 02/14/2011] [Accepted: 02/16/2011] [Indexed: 11/07/2022]
|
36
|
|
37
|
Abstract
Whole-cell biocatalysis utilizes native or recombinant enzymes produced by cellular metabolism to perform synthetically interesting reactions. Besides hydrolases, oxidoreductases represent the most applied enzyme class in industry. Oxidoreductases are attributed a high future potential, especially for applications in the chemical and pharmaceutical industries, as they enable highly interesting chemistry (e.g., the selective oxyfunctionalization of unactivated C-H bonds). Redox reactions are characterized by electron transfer steps that often depend on redox cofactors as additional substrates. Their regeneration typically is accomplished via the metabolism of whole-cell catalysts. Traditionally, studies towards productive redox biocatalysis focused on the biocatalytic enzyme, its activity, selectivity, and specificity, and several successful examples of such processes are running commercially. However, redox cofactor regeneration by host metabolism was hardly considered for the optimization of biocatalytic rate, yield, and/or titer. This article reviews molecular mechanisms of oxidoreductases with synthetic potential and the host redox metabolism that fuels biocatalytic reactions with redox equivalents. The tools discussed in this review for investigating redox metabolism provide the basis for studies aiming at a deeper understanding of the interplay between synthetically active enzymes and metabolic networks. The ultimate goal of rational whole-cell biocatalyst engineering and use for fine chemical production is discussed.
Collapse
|
38
|
Toward systematic metabolic engineering based on the analysis of metabolic regulation by the integration of different levels of information. Biochem Eng J 2009. [DOI: 10.1016/j.bej.2009.06.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|