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Kim SH, Cho JY, Hwang JH, Kim HJ, Oh SJ, Kim HJ, Bhatia SK, Yun J, Lee SH, Yang YH. Revealing the key gene involved in bioplastic degradation from superior bioplastic degrader Bacillus sp. JY35. Int J Biol Macromol 2023:125298. [PMID: 37315675 DOI: 10.1016/j.ijbiomac.2023.125298] [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: 03/15/2023] [Revised: 05/18/2023] [Accepted: 06/02/2023] [Indexed: 06/16/2023]
Abstract
The use of bioplastics, which can alleviate environmental pollution caused by non-degradable bioplastics, has received attention. As there are many types of bioplastics, method that can treat them simultaneously is important. Therefore, Bacillus sp. JY35 which can degrade different types of bioplastics, was screened in previous study. Most types of bioplastics, such as polyhydroxybutyrate (PHB), (P(3HB-co-4HB)), poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS), and polycaprolactone (PCL), can be degraded by esterase family enzymes. To identify the genes that are involved in bioplastic degradation, analysis with whole-genome sequencing was performed. Among the many esterase enzymes, three carboxylesterase and one triacylglycerol lipase were identified and selected based on previous studies. Esterase activity using p-nitrophenyl substrates was measured, and the supernatant of JY35_02679 showed strong emulsion clarification activity compared with others. In addition, when recombinant E. coli was applied to the clear zone test, only the JY35_02679 gene showed activity in the clear zone test with bioplastic containing solid cultures. Further quantitative analysis showed 100 % PCL degradation at 7 days and 45.7 % PBS degradation at 10 days. We identified a gene encoding a bioplastic-degrading enzyme in Bacillus sp. JY35 and successfully expressed the gene in heterologous E. coli, which secreted esterases with broad specificity.
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Affiliation(s)
- Su Hyun Kim
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Jang Yeon Cho
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Jeong Hyeon Hwang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Hyun Jin Kim
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Suk Jin Oh
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Hyun Joong Kim
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea; Institute for Ubiquitous Information Technology and Application, Konkuk University, Seoul, Republic of Korea
| | - Jeonghee Yun
- Department of Forest Products and Biotechnology, Kookmin University, Seoul, Republic of Korea
| | - Sang-Ho Lee
- Department of Pharmacy, College of Pharmacy, Jeju National University, Jeju-si, Republic of Korea
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, Republic of Korea; Institute for Ubiquitous Information Technology and Application, Konkuk University, Seoul, Republic of Korea.
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2
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Goussé M, Dell'Aglio E, Curien G, Borland S, Renoud S, Ranquet C, Chandor-Proust A. E. coli chromosomal-driven expression of NADK2 from A. thaliana: A preferable alternative to plasmid-driven expression for challenging proteins. Protein Expr Purif 2022; 195-196:106090. [PMID: 35346853 DOI: 10.1016/j.pep.2022.106090] [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: 01/07/2022] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 11/25/2022]
Abstract
The expression and purification of large recombinant proteins or protein complexes is problematic for some biotechnology laboratories. Indeed, it is often difficult to obtain enough active proteins to perform biological characterization or reach commercialization, when large proteins or protein complexes are expressed in E. coli via the popular T7-based plasmid-driven expression system. There is also an industrial demand to decrease our dependence on plasmid-driven expression, because of its drawbacks, such as: i) the common use of antibiotics to maintain the plasmid, ii) the issue of plasmid copy number, and iii) the risk of overloading the expression system. Despite all these issues, alternative solutions, such as gene integration in the bacterial chromosome, are rarely employed and their advantages are still a matter of debate. Plant plastidial NAD kinases (NADK; ATP:NAD 2'-phosphotransferase, EC 2.7.1.23) are a classic example of proteins with high molecular weight, that are difficult to express and purify with traditional T7-based technology. We therefore compared plasmid-driven and chromosomal-driven expression of the Arabidopsis thaliana NADK2 protein, using a proprietary counter-selection tool, COLIBELT®, that allows scar-free and marker-free chromosomal modifications. Here we show that chromosomal-driven expression allowed recovery of more active NADK2 protein than classic T7 expression systems, as well as better production, thus confirming that expression from one single chromosomal copy is preferable to plasmid-driven expression and might be appealing for both basic and applied research.
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Affiliation(s)
| | - Elisa Dell'Aglio
- Univ. Grenoble Alpes, CNRS, CEA, INRAe, IRIG-LPCV, Grenoble, France
| | - Gilles Curien
- Univ. Grenoble Alpes, CNRS, CEA, INRAe, IRIG-LPCV, Grenoble, France
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3
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Deb SS, Reshamwala SMS, Lali AM. Activation of alternative metabolic pathways diverts carbon flux away from isobutanol formation in an engineered Escherichia coli strain. Biotechnol Lett 2019; 41:823-836. [PMID: 31093837 DOI: 10.1007/s10529-019-02683-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 05/02/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Metabolic engineering efforts are guided by identifying gene targets for overexpression and/or deletion. Isobutanol, a biofuel candidate, is biosynthesized using the valine biosynthesis pathway and enzymes of the Ehrlich pathway. Most reported studies for isobutanol production in Escherichia coli employ multicopy plasmids, an approach that suffers from disadvantages such as plasmid instability, increased metabolic burden, and use of antibiotics to maintain selection pressure. Cofactor imbalance is another issue that may limit production of isobutanol, as two enzymes of the pathway utilize NADPH as a cofactor. RESULTS To address these issues, we constructed E. coli strains with chromosomally-integrated, codon-optimized isobutanol pathway genes (ilvGM, ilvC, kivd, adh) selected on the basis of their cofactor preferences. Genes involved in diverting pyruvate flux toward fermentation byproducts were deleted. Metabolite analyses of the constructed strains revealed extracellular accumulation of significant amounts of isobutyraldehyde, a pathway intermediate, and the overflow metabolites 2,3-butanediol and acetol. CONCLUSIONS These results demonstrate that the genetic modifications carried out led to activation of alternative pathways that diverted carbon flux toward formation of unwanted metabolites. The present study highlights how precursor metabolites can be metabolized through enzymatic routes that have not been considered important in previous studies due to the different strategies employed therein. The insights gained from the present study will allow rational genetic modification of host cells for production of metabolites of interest.
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Affiliation(s)
- Shalini S Deb
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India
| | - Shamlan M S Reshamwala
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India.
| | - Arvind M Lali
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India
- Department of Chemical Engineering, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India
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4
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Jaén KE, Velazquez D, Delvigne F, Sigala JC, Lara AR. Engineering E. coli for improved microaerobic pDNA production. Bioprocess Biosyst Eng 2019; 42:1457-1466. [PMID: 31079222 DOI: 10.1007/s00449-019-02142-5] [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: 01/13/2019] [Revised: 03/20/2019] [Accepted: 05/02/2019] [Indexed: 02/08/2023]
Abstract
Escherichia coli strains W3110 and BL21 were engineered for the production of plasmid DNA (pDNA) under aerobic and transitions to microaerobic conditions. The gene coding for recombinase A (recA) was deleted in both strains. In addition, the Vitreoscilla hemoglobin (VHb) gene (vgb) was chromosomally inserted and constitutively expressed in each E. coli recA mutant and wild type. The recA inactivation increased the supercoiled pDNA fraction (SCF) in both strains, while VHb expression improved the pDNA production in W3110, but not in BL21. Therefore, a codon-optimized version of vgb was inserted in strain BL21recA-, which, together with W3110recA-vgb+, was tested in cultures with shifts from aerobic to oxygen-limited regimes. VHb expression lowered the accumulation of fermentative by-products in both strains. VHb-expressing cells displayed higher oxidative activity as indicated by the Redox Sensor Green fluorescence, which was more intense in BL21 than in W3110. Furthermore, VHb expression did not change pDNA production in W3110, but decreased it in BL21. These results are useful for understanding the physiological effects of VHb expression in two industrially relevant E. coli strains, and for the selection of a host for pDNA production.
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Affiliation(s)
- Karim E Jaén
- Posgrado en Ciencias Naturales e Ingeniería, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico
| | - Daniela Velazquez
- Posgrado en Ciencias Naturales e Ingeniería, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico
| | - Frank Delvigne
- Gembloux Agro-Bio Tech, TERRA Research and Teaching Centre, Microbial Processes and Interactions (MiPI), University of Liege, Gembloux, Belgium
| | - Juan-Carlos Sigala
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico
| | - Alvaro R Lara
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico.
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Xu Y, Mao W, Gao W, Chi Z, Chi Z, Liu G. Efficient production of a recombinant ι-carrageenase in Brevibacillus choshinensis using a new integrative vector for the preparation of ι-carrageenan oligosaccharides. Process Biochem 2019. [DOI: 10.1016/j.procbio.2018.09.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lara AR, Jaén KE, Sigala JC, Mühlmann M, Regestein L, Büchs J. Characterization of Endogenous and Reduced Promoters for Oxygen-Limited Processes Using Escherichia coli. ACS Synth Biol 2017; 6:344-356. [PMID: 27715021 DOI: 10.1021/acssynbio.6b00233] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Oxygen limitation can be used as a simple environmental inducer for the expression of target genes. However, there is scarce information on the characteristics of microaerobic promoters potentially useful for cell engineering and synthetic biology applications. Here, we characterized the Vitreoscilla hemoglobin promoter (Pvgb) and a set of microaerobic endogenous promoters in Escherichia coli. Oxygen-limited cultures at different maximum oxygen transfer rates were carried out. The FMN-binding fluorescent protein (FbFP), which is a nonoxygen dependent marker protein, was used as a reporter. Fluorescence and fluorescence emission rates under oxygen-limited conditions were the highest when FbFP was under transcriptional control of PadhE, Ppfl and Pvgb. The lengths of the E. coli endogenous promoters were shortened by 60%, maintaining their key regulatory elements. This resulted in improved promoter activity in most cases, particularly for PadhE, Ppfl and PnarK. Selected promoters were also evaluated using an engineered E. coli strain expressing Vitreoscilla hemoglobin (VHb). The presence of the VHb resulted in a better repression using these promoters under aerobic conditions, and increased the specific growth and fluorescence emission rates under oxygen-limited conditions. These results are useful for the selection of promoters for specific applications and for the design of modified artificial promoters.
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Affiliation(s)
- Alvaro R. Lara
- Departamento
de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa. Av. Vasco de Quiroga 4871, Santa
Fe, C.P. 05348, Mexico City, México
| | - Karim E. Jaén
- Departamento
de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa. Av. Vasco de Quiroga 4871, Santa
Fe, C.P. 05348, Mexico City, México
| | - Juan-Carlos Sigala
- Departamento
de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa. Av. Vasco de Quiroga 4871, Santa
Fe, C.P. 05348, Mexico City, México
| | - Martina Mühlmann
- RWTH Aachen University, AVT - Biochemical Engineering, Worringer Weg 1, 52074 Aachen, Germany
| | - Lars Regestein
- RWTH Aachen University, AVT - Biochemical Engineering, Worringer Weg 1, 52074 Aachen, Germany
| | - Jochen Büchs
- RWTH Aachen University, AVT - Biochemical Engineering, Worringer Weg 1, 52074 Aachen, Germany
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7
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Mejía-Caballero A, de Anda R, Hernández-Chávez G, Rogg S, Martinez A, Bolívar F, Castaño VM, Gosset G. Biosynthesis of catechol melanin from glycerol employing metabolically engineered Escherichia coli. Microb Cell Fact 2016; 15:161. [PMID: 27659593 PMCID: PMC5034560 DOI: 10.1186/s12934-016-0561-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Melanins comprise a chemically-diverse group of polymeric pigments whose function is related to protection against physical and chemical stress factors. These polymers have current and potential applications in the chemical, medical, electronics and materials industries. The biotechnological production of melanins offers the possibility of obtaining these pigments in pure form and relatively low cost. In this study, Escherichia coli strains were engineered to evaluate the production of melanin from supplemented catechol or from glycerol-derived catechol produced by an Escherichia coli strain generated by metabolic engineering. RESULTS It was determined that an improved mutant version of the tyrosinase from Rhizobium etli (MutmelA), could employ catechol as a substrate to generate melanin. Strain E. coli W3110 expressing MutmelA was grown in bioreactor batch cultures with catechol supplemented in the medium. Under these conditions, 0.29 g/L of catechol melanin were produced. A strain with the capacity to synthesize catechol melanin from a simple carbon source was generated by integrating the gene MutmelA into the chromosome of E. coli W3110 trpD9923, that has been modified to produce catechol by the expression of genes encoding a feedback inhibition resistant version of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase, transketolase and anthranilate 1,2-dioxygenase from Pseudomonas aeruginosa PAO1. In batch cultures with this strain employing complex medium with 40 g/L glycerol as a carbon source, 1.21 g/L of catechol melanin were produced. The melanin was analysed by employing Fourier transform infrared spectroscopy, revealing the expected characteristics for a catechol-derived polymer. CONCLUSIONS This constitutes the first report of an engineered E. coli strain and a fermentation process for producing a catechol melanin from a simple carbon source (glycerol) at gram level, opening the possibility of generating a large quantity of this polymer for its detailed characterization and the development of novel applications.
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Affiliation(s)
- Alejandra Mejía-Caballero
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, MOR, CP 62271, Mexico
| | - Ramón de Anda
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, MOR, CP 62271, Mexico
| | - Georgina Hernández-Chávez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, MOR, CP 62271, Mexico
| | - Simone Rogg
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Santiago de Querétaro, Mexico
| | - Alfredo Martinez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, MOR, CP 62271, Mexico
| | - Francisco Bolívar
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, MOR, CP 62271, Mexico
| | - Victor M Castaño
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Santiago de Querétaro, Mexico
| | - Guillermo Gosset
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, MOR, CP 62271, Mexico.
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8
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Baert J, Delepierre A, Telek S, Fickers P, Toye D, Delamotte A, Lara AR, Jaén KE, Gosset G, Jensen PR, Delvigne F. Microbial population heterogeneity versus bioreactor heterogeneity: Evaluation of Redox Sensor Green as an exogenous metabolic biosensor. Eng Life Sci 2016. [DOI: 10.1002/elsc.201500149] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Jonathan Baert
- Gembloux Agro-Bio Tech; Microbial Processes and Interactions (MiPI); University of Liège; Gembloux Belgium
| | - Anissa Delepierre
- Gembloux Agro-Bio Tech; Microbial Processes and Interactions (MiPI); University of Liège; Gembloux Belgium
| | - Samuel Telek
- Gembloux Agro-Bio Tech; Microbial Processes and Interactions (MiPI); University of Liège; Gembloux Belgium
| | - Patrick Fickers
- Gembloux Agro-Bio Tech; Microbial Processes and Interactions (MiPI); University of Liège; Gembloux Belgium
| | - Dominique Toye
- Department of Chemical Engineering-Product; Environment and Processes (PEPs); University of Liège; Liège Belgium
| | - Anne Delamotte
- Department of Chemical Engineering-Product; Environment and Processes (PEPs); University of Liège; Liège Belgium
| | - Alvaro R. Lara
- Departamento de Procesos y Tecnología; Universidad Autónoma Metropolitana-Cuajimalpa; Col. Santa Fe Cuajimalpa México D. F., Mexico
| | - Karim E. Jaén
- Departamento de Procesos y Tecnología; Universidad Autónoma Metropolitana-Cuajimalpa; Col. Santa Fe Cuajimalpa México D. F., Mexico
| | - Guillermo Gosset
- Instituto de Biotecnología; Universidad Nacional Autónoma de México; Cuernavaca Morelos México
| | - Peter R. Jensen
- National Food Institute; Technical University of Denmark (DTU); Lyngby Denmark
| | - Frank Delvigne
- Gembloux Agro-Bio Tech; Microbial Processes and Interactions (MiPI); University of Liège; Gembloux Belgium
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Deb SS, Reshamwala SMS, Lali AM. A series of template plasmids for Escherichia coli genome engineering. J Microbiol Methods 2016; 125:49-57. [PMID: 27071533 DOI: 10.1016/j.mimet.2016.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 12/16/2022]
Abstract
Metabolic engineering strategies often employ multi-copy episomal vectors to overexpress genes. However, chromosome-based overexpression is preferred as it avoids the use of selective pressure and reduces metabolic burden on the cell. We have constructed a series of template plasmids for λ Red-mediated Escherichia coli genome engineering. The template plasmids allow construction of genome integrating cassettes that can be used to integrate single copies of DNA sequences at predetermined sites or replace promoter regions. The constructed cassettes provide flexibility in terms of expression levels achieved and antibiotics used for selection, as well as allowing construction of marker-free strains. The modular design of the template plasmids allows replacement of genetic parts to construct new templates. Gene integration and promoter replacement using the template plasmids are illustrated.
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Affiliation(s)
- Shalini S Deb
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai 400019, Maharashtra, India
| | - Shamlan M S Reshamwala
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai 400019, Maharashtra, India.
| | - Arvind M Lali
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai 400019, Maharashtra, India; Department of Chemical Engineering, Institute of Chemical Technology, Mumbai 400019, Maharashtra, India
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Sabido A, Sigala JC, Hernández-Chávez G, Flores N, Gosset G, Bolívar F. Physiological and transcriptional characterization of Escherichia coli strains lacking interconversion of phosphoenolpyruvate and pyruvate when glucose and acetate are coutilized. Biotechnol Bioeng 2014; 111:1150-60. [PMID: 24375081 PMCID: PMC4278548 DOI: 10.1002/bit.25177] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 12/05/2013] [Accepted: 12/18/2013] [Indexed: 01/01/2023]
Abstract
Phosphoenolpyruvate (PEP) is a precursor involved in the biosynthesis of aromatics and other valuable compounds in Escherichia coli. The PEP:carbohydrate phosphotransferase system (PTS) is the major glucose transport system and the largest PEP consumer. To increase intracellular PEP availability for aromatics production purposes, mutant strains of E. coli JM101 devoid of the ptsHIcrr operon (PB11 strain) have been previously generated. In this derivative, transport and growth rate on glucose decreased significantly. A laboratory evolved strain derived from PB11 that partially recovered its growth capacity on glucose was named PB12. In the present study, we blocked carbon skeletons interchange between PEP and pyruvate (PYR) in these ptsHIcrr− strains by deleting the pykA, pykF, and ppsA genes. The PB11 pykAF−ppsA− strain exhibited no growth on glucose or acetate alone, but it was viable when both substrates were consumed simultaneously. In contrast, the PB12 pykAF−ppsA− strain displayed a low growth rate on glucose or acetate alone, but in the mixture, growth was significantly improved. RT-qPCR expression analysis of PB11 pykAF−ppsA− growing with both carbon sources showed a downregulation of all central metabolic pathways compared with its parental PB11 strain. Under the same conditions, transcription of most of the genes in PB12 pykAF−ppsA− did not change, and few like aceBAK, sfcA, and poxB were overexpressed compared with PB12. We explored the aromatics production capabilities of both ptsHIcrr−pykAF−ppsA− strains and the engineered PB12 pykAF−ppsA−tyrR−pheAev2+/pJLBaroGfbrtktA enhanced the yield of aromatic compounds when coutilizing glucose and acetate compared with the control strain PB12 tyrR−pheAev2+/pJLBaroGfbrtktA. Biotechnol. Bioeng. 2014;111: 1150–1160. © 2013 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Andrea Sabido
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mor., México
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11
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Baumgärtner F, Seitz L, Sprenger GA, Albermann C. Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2'-fucosyllactose. Microb Cell Fact 2013; 12:40. [PMID: 23635327 PMCID: PMC3655002 DOI: 10.1186/1475-2859-12-40] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 04/22/2013] [Indexed: 12/23/2022] Open
Abstract
Background The trisaccharide 2′-fucosyllactose (2′-FL) is one of the most abundant oligosaccharides found in human milk. Due to its prebiotic and anti-infective properties, 2′-FL is discussed as nutritional additive for infant formula. Besides chemical synthesis and extraction from human milk, 2′-FL can be produced enzymatically in vitro and in vivo. The most promising approach for a large-scale formation of 2′-FL is the whole cell biosynthesis in Escherichia coli by intracellular synthesis of GDP-L-fucose and subsequent fucosylation of lactose with an appropriate α1,2-fucosyltransferase. Even though whole cell approaches have been demonstrated for the synthesis of 2′-FL, further improvements of the engineered E. coli host are required to increase product yields. Furthermore, an antibiotic-free method of whole cell synthesis of 2′-FL is desirable to simplify product purification and to avoid traces of antibiotics in a product with nutritional purpose. Results Here we report the construction of the first selection marker-free E. coli strain that produces 2′-FL from lactose and glycerol. To construct this strain, recombinant genes of the de novo synthesis pathway for GDP-L-fucose as well as the gene for the H. pylori fucosyltransferase futC were integrated into the chromosome of E. coli JM109 by using the λ-Red recombineering technique. Strains carrying additional copies of the futC gene and/or the gene fkp (from Bacteroides fragilis) for an additional salvage pathway for GDP-L-fucose production were used and shown to further improve production of 2′-FL in shake flask experiments. An increase of the intracellular GDP-L-fucose concentration by expression of fkp gene as well as an additional copy of the futC gene lead to an enhanced formation of 2′-FL. Using an improved production strain, feasibility of large scale 2′-FL production was demonstrated in an antibiotic-free fed-batch fermentation (13 l) with a final 2′-FL concentration of 20.28 ± 0.83 g l-1 and a space-time-yield of 0.57 g l-1 h-1. Conclusions By chromosomal integration of recombinant genes, altering the copy number of these genes and analysis of 2′-FL and intracellular GDP-L-fucose levels, we were able to construct and improve the first selection marker-free E. coli strain which is capable to produce 2′-FL without the use of expression plasmids. Analysis of intracellular GDP-L-fucose levels identified the de novo synthesis pathway of GDP-L-fucose as one bottleneck in 2′-FL production. In antibiotic-free fed-batch fermentation with an improved strain, scale-up of 2′-FL could be demonstrated.
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