1
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Guo X, Farag M, Qian N, Yu X, Ni A, Ma Y, Yu W, King MR, Liu V, Lee J, Zare RN, Min W, Pappu RV, Dai Y. Biomolecular condensates can function as inherent catalysts. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.06.602359. [PMID: 39026887 PMCID: PMC11257451 DOI: 10.1101/2024.07.06.602359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
We report the discovery that chemical reactions such as ATP hydrolysis can be catalyzed by condensates formed by intrinsically disordered proteins (IDPs), which themselves lack any intrinsic ability to function as enzymes. This inherent catalytic feature of condensates derives from the electrochemical environments and the electric fields at interfaces that are direct consequences of phase separation. The condensates we studied were capable of catalyzing diverse hydrolysis reactions, including hydrolysis and radical-dependent breakdown of ATP whereby ATP fully decomposes to adenine and multiple carbohydrates. This distinguishes condensates from naturally occurring ATPases, which can only catalyze the dephosphorylation of ATP. Interphase and interfacial properties of condensates can be tuned via sequence design, thus enabling control over catalysis through sequence-dependent electrochemical features of condensates. Incorporation of hydrolase-like synthetic condensates into live cells enables activation of transcriptional circuits that depend on products of hydrolysis reactions. Inherent catalytic functions of condensates, which are emergent consequences of phase separation, are likely to affect metabolic regulation in cells.
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Affiliation(s)
- Xiao Guo
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Mina Farag
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Naixin Qian
- Department of Chemistry, Columbia University, New York, NY 10027
| | - Xia Yu
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Anton Ni
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Yuefeng Ma
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Wen Yu
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Matthew R. King
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Vicky Liu
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Joonho Lee
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Richard N. Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Wei Min
- Department of Chemistry, Columbia University, New York, NY 10027
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
| | - Yifan Dai
- Department of Biomedical Engineering, Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130
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2
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Rajacharya GH, Sharma A, Yazdani SS. Proteomics and metabolic burden analysis to understand the impact of recombinant protein production in E. coli. Sci Rep 2024; 14:12271. [PMID: 38806637 PMCID: PMC11133349 DOI: 10.1038/s41598-024-63148-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/24/2024] [Indexed: 05/30/2024] Open
Abstract
The impact of recombinant protein production (RPP) on host cells and the metabolic burden associated with it undermine the efficiency of the production system. This study utilized proteomics to investigate the dynamics of parent and recombinant cells induced at different time points for RPP. The results revealed significant changes in both transcriptional and translational machinery that may have impacted the metabolic burden, growth rate of the culture and the RPP. The timing of protein synthesis induction also played a critical role in the fate of the recombinant protein within the host cell, affecting protein and product yield. The study identified significant differences in the expression of proteins involved in fatty acid and lipid biosynthesis pathways between two E. coli host strains (M15 and DH5⍺), with the E. coli M15 strain demonstrating superior expression characteristics for the recombinant protein. Overall, these findings contribute to the knowledge base for rational strain engineering for optimized recombinant protein production.
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Affiliation(s)
- Girish H Rajacharya
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India
- DBT-ICGEB Centre for Advanced Bio-Energy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- School of Interdisciplinary Research (SIRe), Indian Institute of Technology, New Delhi, India
| | - Ashima Sharma
- DBT-ICGEB Centre for Advanced Bio-Energy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Department of Life Sciences, J.C. Bose University of Science and Technology, YMCA, Faridabad, Haryana, India
| | - Syed Shams Yazdani
- Microbial Engineering Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
- DBT-ICGEB Centre for Advanced Bio-Energy Research, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.
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3
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Matsuyama C, Seike T, Okahashi N, Niide T, Hara KY, Hirono-Hara Y, Ishii J, Shimizu H, Toya Y, Matsuda F. Metabolome analysis of metabolic burden in Escherichia coli caused by overexpression of green fluorescent protein and delta-rhodopsin. J Biosci Bioeng 2024; 137:187-194. [PMID: 38281859 DOI: 10.1016/j.jbiosc.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/18/2023] [Accepted: 12/04/2023] [Indexed: 01/30/2024]
Abstract
Overexpression of proteins by introducing a DNA vector is among the most important tools for the metabolic engineering of microorganisms such as Escherichia coli. Protein overexpression imposes a burden on metabolism because metabolic pathways must supply building blocks for protein and DNA synthesis. Different E. coli strains have distinct metabolic capacities. In this study, two proteins were overexpressed in four E. coli strains (MG1655(DE3), W3110(DE3), BL21star(DE3), and Rosetta(DE3)), and their effects on metabolic burden were investigated. Metabolomic analysis showed that E. coli strains overexpressing green fluorescent protein had decreased levels of several metabolites, with a positive correlation between the number of reduced metabolites and green fluorescent protein expression levels. Moreover, nucleic acid-related metabolites decreased, indicating a metabolic burden in the E. coli strains, and the growth rate and protein expression levels were improved by supplementation with the five nucleosides. In contrast, two strains overexpressing delta rhodopsin, a microbial membrane rhodopsin from Haloterrigena turkmenica, led to a metabolic burden and decrease in the amino acids Ala, Val, Leu, Ile, Thr, Phe, Asp, and Trp, which are the most frequent amino acids in the delta rhodopsin protein sequence. The metabolic burden caused by protein overexpression was influenced by the metabolic capacity of the host strains and the sequences of the overexpressed proteins. Detailed characterization of the effects of protein expression on the metabolic state of engineered cells using metabolomics will provide insights into improving the production of target compounds.
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Affiliation(s)
- Chinatsu Matsuyama
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Taisuke Seike
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Nobuyuki Okahashi
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan; Osaka University Shimadzu Omics Innovation Research Laboratories, Osaka University, Osaka 565-0871, Japan
| | - Teppei Niide
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Kiyotaka Y Hara
- Department of Environmental and Life Sciences, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | | | - Jun Ishii
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501, Japan
| | - Hiroshi Shimizu
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Yoshihiro Toya
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Fumio Matsuda
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan; Osaka University Shimadzu Omics Innovation Research Laboratories, Osaka University, Osaka 565-0871, Japan.
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4
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Sun Y, Xu J, Zhou H, Zhang H, Wu J, Yang L. Recombinant Protein Expression Chassis Library of Vibrio natriegens by Fine-Tuning the Expression of T7 RNA Polymerase. ACS Synth Biol 2023; 12:555-564. [PMID: 36719178 DOI: 10.1021/acssynbio.2c00562] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Vibrio natriegens is the fastest-growing bacteria, and its doubling time is less than 10 min. At present, the T7 expression system has been introduced into V. natriegens for heterologous protein expression, including the commercial strain Vmax1 and the variant VnDX,2 which is a backup expression chassis of Escherichia coli BL21(DE3). However, the strength of the existing T7 expression system is not optimal for every recombinant protein. The different expression strengths of T7 RNA polymerase (T7 RNAP) can be obtained by changing the promoter and ribosome binding site (RBS) sequences of T7 RNAP at different transcription and translation levels. In this work, we obtained a robust VnDX variant library with the fine-tuning T7 RNAP using the industrially used enzyme glucose dehydrogenase (GDH) as the reporter protein. Among this library, the variant VnDX-tet, whose promoter of T7 RNAP was changed from PlacUV5 to Ptet, showed that the reporter enzyme GDH activity was increased by 109% by the T7 expression system. Similarly, variants with different T7 RNAP translation levels were obtained by changing RBS sequences upstream of T7 RNAP, and the results showed that the variant VnDX-RBS12/pGDH had the highest GDH activity, which increased by 12.6%. The VnDX variant library constructed in this study with different T7 expression strengths provides a choice for expressing various recombinant proteins, greatly expanding the application of V. natriegens.
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Affiliation(s)
- Yijie Sun
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Jiaqi Xu
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Haisheng Zhou
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Hongyu Zhang
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China
| | - Jianping Wu
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Lirong Yang
- Institute of Bioengineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China
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5
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High-Throughput Expression of Inclusion Bodies on an Automated Platform. Methods Mol Biol 2023; 2617:31-47. [PMID: 36656515 DOI: 10.1007/978-1-0716-2930-7_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In bioprocesses, which target the production of recombinant proteins as inclusion bodies, the upstream process has a decisive influence on the downstream operations, especially regarding cell disruption, inclusion body purity and composition, and refolding yield. Therefore, optimization of the processes in fed-batch mode is a major issue, and screening for strains and process conditions are performed in highly labor, time and cost intensive shake flasks or multiwell plates. Thus, high-throughput experiments performed similar to the industrial operating conditions offer a possibility to develop efficient and robust upstream processes. We present here an automated platform for Escherichia coli fed-batch cultivations in parallelized minibioreactors. The platform allows execution of experiments under multiple conditions while allowing for real-time monitoring of critical process parameters and a controlled fermentation environment. By this, the main factors that affect yields and quality of inclusion bodies can be investigated, speeding up the development process significantly.
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6
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Kitagawa W, Hata M. Development of Efficient Genome-Reduction Tool Based on Cre/ loxP System in Rhodococcus erythropolis. Microorganisms 2023; 11:microorganisms11020268. [PMID: 36838232 PMCID: PMC9959502 DOI: 10.3390/microorganisms11020268] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
Rhodococcus has been extensively studied for its excellent ability to degrade artificial chemicals and its capability to synthesize biosurfactants and antibiotics. In recent years, studies have attempted to use Rhodococcus as a gene expression host. Various genetic tools, such as plasmid vectors, transposon mutagenesis, and gene disruption methods have been developed for use in Rhodococcus; however, no effective method has been reported for performing large-size genome reduction. Therefore, the present study developed an effective plasmid-curing method using the levansucrase-encoding sacB gene and a simple two-step genome-reduction method using a modified Cre/loxP system. For the results, R. erythropolis JCM 2895 was used as the model; a mutant strain that cured all four plasmids and deleted seven chromosomal regions was successfully obtained in this study. The total DNA deletion size was >600 kb, which corresponds mostly to 10% of the genome size. Using this method, a genome-structure-stabilized and unfavorable gene/function-lacking host strain can be created in Rhodococcus. This genetic tool will help develop and improve Rhodococcus strains for various industrial and environmental applications.
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Affiliation(s)
- Wataru Kitagawa
- Bioproduction Research Institute, National Institute of Advanced Industrial and Technology (AIST), Sapporo 062-8517, Japan
- Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Correspondence:
| | - Miyako Hata
- Bioproduction Research Institute, National Institute of Advanced Industrial and Technology (AIST), Sapporo 062-8517, Japan
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7
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Moxley WC, Eiteman MA. Pyruvate Production by Escherichia coli by Use of Pyruvate Dehydrogenase Variants. Appl Environ Microbiol 2021; 87:e0048721. [PMID: 33863707 PMCID: PMC8315933 DOI: 10.1128/aem.00487-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/10/2021] [Indexed: 11/20/2022] Open
Abstract
Altering metabolic flux at a key branch point in metabolism has commonly been accomplished through gene knockouts or by modulating gene expression. An alternative approach to direct metabolic flux preferentially toward a product is decreasing the activity of a key enzyme through protein engineering. In Escherichia coli, pyruvate can accumulate from glucose when carbon flux through the pyruvate dehydrogenase complex is suppressed. Based on this principle, 16 chromosomally expressed AceE variants were constructed in E. coli C and compared for growth rate and pyruvate accumulation using glucose as the sole carbon source. To prevent conversion of pyruvate to other products, the strains also contained deletions in two nonessential pathways: lactate dehydrogenase (ldhA) and pyruvate oxidase (poxB). The effect of deleting phosphoenolpyruvate synthase (ppsA) on pyruvate assimilation was also examined. The best pyruvate-accumulating strains were examined in controlled batch and continuous processes. In a nitrogen-limited chemostat process at steady-state growth rates of 0.15 to 0.28 h-1, an engineered strain expressing the AceE[H106V] variant accumulated pyruvate at a yield of 0.59 to 0.66 g pyruvate/g glucose with a specific productivity of 0.78 to 0.92 g pyruvate/g cells·h. These results provide proof of concept that pyruvate dehydrogenase complex variants can effectively shift carbon flux away from central carbon metabolism to allow pyruvate accumulation. This approach can potentially be applied to other key enzymes in metabolism to direct carbon toward a biochemical product. IMPORTANCE Microbial production of biochemicals from renewable resources has become an efficient and cost-effective alternative to traditional chemical synthesis methods. Metabolic engineering tools are important for optimizing a process to perform at an economically feasible level. This study describes an additional tool to modify central metabolism and direct metabolic flux to a product. We have shown that variants of the pyruvate dehydrogenase complex can direct metabolic flux away from cell growth to increase pyruvate production in Escherichia coli. This approach could be paired with existing strategies to optimize metabolism and create industrially relevant and economically feasible processes.
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Affiliation(s)
- W. Chris Moxley
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Mark A. Eiteman
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia, USA
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8
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Von den Eichen N, Bromig L, Sidarava V, Marienberg H, Weuster-Botz D. Automated multi-scale cascade of parallel stirred-tank bioreactors for fast protein expression studies. J Biotechnol 2021; 332:103-113. [PMID: 33845064 DOI: 10.1016/j.jbiotec.2021.03.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 11/18/2022]
Abstract
Automation, parallelization and autonomous operation of standard lab equipment, usually applied for manual bioprocess development, is considered as the key for reduction of bioprocess development time and costs. An automated bioreactor system with 4 stirred-tank bioreactors on a L-scale was combined with a custom-made biomass transfer system to distribute the cell suspensions produced on the L-scale into 48 parallel stirred-tank bioreactors on a mL-scale. Afterwards parallel protein expression studies automated by a liquid handling system with integrated fluorescence reader were performed. Isopropyl β-D-1-thiogalactopyranoside-induced (IPTG) expression of the red fluorescence protein mCherry was studied as an example of using fed-batch processes with recombinant Escherichia coli. In a first automated study, IPTG concentrations were varied in 48 parallel fed-batch processes with E. coli cells produced at a growth rate of 0.1 h-1 on an L-scale and transferred automatically to the mL-scale. The mCherry expression rate increased with increasing inducer concentration until the highest protein expression rate was observed at > 9 μM IPTG. In a second automated study, the growth rate of E. coli was varied between 0.1-0.2 h-1 in parallelly-operated stirred-tank bioreactors on a L-scale. The cells were automatically transferred and distributed into the stirred-tank bioreactors on a mL-scale and the concentration of the inducer IPTG was varied as before in parallel fed-batch processes. An increased growth rate during the production of the recombinant E. coli cells and/or higher cell densities during protein expression resulted in the increased IPTG concentrations necessary to achieve identical expression rates compared to a growth rate of 0.1 h-1 with the exception of very low inducer concentrations and inducer concentrations in excess. The new automated multi-scale cascade of parallel stirred-tank bioreactors should easily be applicable for performing fast optimisation studies with other microbial production systems and will have the potential to reduce bioprocess development time and staff assignment considerably.
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Affiliation(s)
- Nikolas Von den Eichen
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Lukas Bromig
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Valeryia Sidarava
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Hannah Marienberg
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
| | - Dirk Weuster-Botz
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany.
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9
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Ni Z, Li Z, Wu J, Ge Y, Liao Y, Yuan L, Chen X, Yao J. Multi-Path Optimization for Efficient Production of 2'-Fucosyllactose in an Engineered Escherichia coli C41 (DE3) Derivative. Front Bioeng Biotechnol 2020; 8:611900. [PMID: 33425876 PMCID: PMC7793955 DOI: 10.3389/fbioe.2020.611900] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 11/13/2020] [Indexed: 12/21/2022] Open
Abstract
2′-fucosyllactose (2′-FL), one of the simplest but most abundant oligosaccharides in human milk, has been demonstrated to have many positive benefits for the healthy development of newborns. However, the high-cost production and limited availability restrict its widespread use in infant nutrition and further research on its potential functions. In this study, on the basis of previous achievements, we developed a powerful cell factory by using a lacZ-mutant Escherichia coli C41 (DE3)ΔZ to ulteriorly increase 2′-FL production by feeding inexpensive glycerol. Initially, we co-expressed the genes for GDP-L-fucose biosynthesis and heterologous α-1,2-fucosyltransferase in C41(DE3)ΔZ through different plasmid-based expression combinations, functionally constructing a preferred route for 2′-FL biosynthesis. To further boost the carbon flux from GDP-L-fucose toward 2′-FL synthesis, deletion of chromosomal genes (wcaJ, nudD, and nudK) involved in the degradation of the precursors GDP-L-fucose and GDP-mannose were performed. Notably, the co-introduction of two heterologous positive regulators, RcsA and RcsB, was confirmed to be more conducive to GDP-L-fucose formation and thus 2′-FL production. Further a genomic integration of an individual copy of α-1,2-fucosyltransferase gene, as well as the preliminary optimization of fermentation conditions enabled the resulting engineered strain to achieve a high titer and yield. By collectively taking into account the intracellular lactose utilization, GDP-L-fucose availability, and fucosylation activity for 2′-FL production, ultimately a highest titer of 2′-FL in our optimized conditions reached 6.86 g/L with a yield of 0.92 mol/mol from lactose in the batch fermentation. Moreover, the feasibility of mass production was demonstrated in a 50-L fed-batch fermentation system in which a maximum titer of 66.80 g/L 2′-FL was achieved with a yield of 0.89 mol 2′-FL/mol lactose and a productivity of approximately 0.95 g/L/h 2′-FL. As a proof of concept, our preliminary 2′-FL production demonstrated a superior production performance, which will provide a promising candidate process for further industrial production.
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Affiliation(s)
- Zhijian Ni
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Zhongkui Li
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Jinyong Wu
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,Wuhan Zhongke Optics Valley Green Biotechnology Co. Ltd., Wuhan, China
| | - Yuanfei Ge
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Yingxue Liao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
| | - Lixia Yuan
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,Wuhan Zhongke Optics Valley Green Biotechnology Co. Ltd., Wuhan, China
| | - Xiangsong Chen
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,Wuhan Zhongke Optics Valley Green Biotechnology Co. Ltd., Wuhan, China
| | - Jianming Yao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.,University of Science and Technology of China, Hefei, China
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10
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Sun XM, Zhang ZX, Wang LR, Wang JG, Liang Y, Yang HF, Tao RS, Jiang Y, Yang JJ, Yang S. Downregulation of T7 RNA polymerase transcription enhances pET-based recombinant protein production in Escherichia coli BL21 (DE3) by suppressing autolysis. Biotechnol Bioeng 2020; 118:153-163. [PMID: 32897579 DOI: 10.1002/bit.27558] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/25/2020] [Accepted: 08/30/2020] [Indexed: 12/15/2022]
Abstract
Escherichia coli BL21 (DE3) is an excellent and widely used host for recombinant protein production. Many variant hosts were developed from BL21 (DE3), but improving the expression of specific proteins remains a major challenge in biotechnology. In this study, we found that when BL21 (DE3) overexpressed glucose dehydrogenase (GDH), a significant industrial enzyme, severe cell autolysis was induced. Subsequently, we observed this phenomenon in the expression of 10 other recombinant proteins. This precludes a further increase of the produced enzyme activity by extending the fermentation time, which is not conducive to the reduction of industrial enzyme production costs. Analysis of membrane structure and messenger RNA expression analysis showed that cells could underwent a form of programmed cell death (PCD) during the autolysis period. However, blocking three known PCD pathways in BL21 (DE3) did not completely alleviate autolysis completely. Consequently, we attempted to develop a strong expression host resistant to autolysis by controlling the speed of recombinant protein expression. To find a more suitable protein expression rate, the high- and low-strength promoter lacUV5 and lac were shuffled and recombined to yield the promoter variants lacUV5-1A and lac-1G. The results showed that only one base in lac promoter needs to be changed, and the A at the +1 position was changed to a G, resulting in the improved host BL21 (DE3-lac1G), which resistant to autolysis. As a consequence, the GDH activity at 43 h was greatly increased from 37.5 to 452.0 U/ml. In scale-up fermentation, the new host was able to produce the model enzyme with a high rate of 89.55 U/ml/h at 43 h, compared to only 3 U/ml/h achieved using BL21 (DE3). Importantly, BL21 (DE3-lac1G) also successfully improved the production of 10 other enzymes. The engineered E. coli strain constructed in this study conveniently optimizes recombinant protein overexpression by suppressing cell autolysis, and shows great potential for industrial applications.
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Affiliation(s)
- Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Zi-Xu Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Ling-Ru Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, Jiangsu, China
| | | | - Yan Liang
- HuaRui Biotechnology Company, Huzhou, Zhejiang, China
| | - Hai-Feng Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rong-Sheng Tao
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou, Zhejiang, China
| | - Yu Jiang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou, Zhejiang, China
| | - Jun-Jie Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.,Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou, Zhejiang, China
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.,Huzhou Center of Industrial Biotechnology, Shanghai Institutes for Biological Sciences, Huzhou, Zhejiang, China
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11
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Li Z, Rinas U. Recombinant protein production associated growth inhibition results mainly from transcription and not from translation. Microb Cell Fact 2020; 19:83. [PMID: 32252765 PMCID: PMC7137236 DOI: 10.1186/s12934-020-01343-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/26/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Recombinant protein production can be stressful to the host organism. The extent of stress is determined by the specific properties of the recombinant transcript and protein, by the rates of transcription and translation, and by the environmental conditions encountered during the production process. RESULTS The impact of the transcription of the T7-promoter controlled genes encoding human basic fibroblast growth factor (hFGF-2) and green fluorescent protein (GFP) as well as the translation into the recombinant protein on the growth properties of the production host E. coli BL21(DE3) were investigated. This was done by using expression vectors where the promoter region or the ribosome binding site(s) or both were removed. It is shown that already transcription without protein translation imposes a metabolic burden on the host cell. Translation of the transcript into large amounts of a properly folded protein does not show any effect on cell growth in the best case, e.g. high-level production of GFP in Luria-Bertani medium. However, translation appears to contribute to the metabolic burden if it is connected to protein folding associated problems, e.g. inclusion body formation. CONCLUSION The so-called metabolic burden of recombinant protein production is mainly attributed to transcription but can be enhanced through translation and those processes following translation (e.g. protein folding and degradation, heat-shock responses).
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Affiliation(s)
- Zhaopeng Li
- Leibniz University of Hannover, Technical Chemistry-Life Science, Callinstr. 5, 30167 Hannover, Germany
| | - Ursula Rinas
- Leibniz University of Hannover, Technical Chemistry-Life Science, Callinstr. 5, 30167 Hannover, Germany
- Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Brunswick, Germany
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12
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Gomes L, Monteiro G, Mergulhão F. The Impact of IPTG Induction on Plasmid Stability and Heterologous Protein Expression by Escherichia coli Biofilms. Int J Mol Sci 2020; 21:ijms21020576. [PMID: 31963160 PMCID: PMC7013871 DOI: 10.3390/ijms21020576] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 11/30/2022] Open
Abstract
This work assesses the effect of chemical induction with isopropyl β-D-1-thiogalactopyranoside (IPTG) on the expression of enhanced green fluorescent protein (eGFP) by planktonic and biofilm cells of Escherichia coli JM109(DE3) transformed with a plasmid containing a T7 promoter. It was shown that induction negatively affected the growth and viability of planktonic cultures, and eGFP production did not increase. Heterologous protein production was not limited by gene dosage or by transcriptional activity. Results suggest that plasmid maintenance at high copy number imposes a metabolic burden that precludes high level expression of the heterologous protein. In biofilm cells, the inducer avoided the overall decrease in the amount of expressed eGFP, although this was not correlated with the gene dosage. Higher specific production levels were always attained with biofilm cells and it seems that while induction of biofilm cells shifts their metabolism towards the maintenance of heterologous protein concentration, in planktonic cells the cellular resources are directed towards plasmid replication and growth.
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Affiliation(s)
- Luciana Gomes
- LEPABE—Department of Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal;
| | - Gabriel Monteiro
- iBB—Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal;
| | - Filipe Mergulhão
- LEPABE—Department of Chemical Engineering, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal;
- Correspondence: ; Tel.: +351-225081668
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13
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Advances in the Metabolic Engineering of Escherichia coli for the Manufacture of Monoterpenes. Catalysts 2019. [DOI: 10.3390/catal9050433] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Monoterpenes are commonly applied as pharmaceuticals and valuable chemicals in various areas. The bioproduction of valuable monoterpenes in prokaryotic microbial hosts, such as E. coli, has progressed considerably thanks to the development of different outstanding approaches. However, the large-scale production of monoterpenes still presents considerable limitations. Thus, process development warrants further investigations. This review discusses the endogenous methylerythritol-4-phosphate-dependent pathway engineering and the exogenous mevalonate-dependent isoprenoid pathway introduction, as well as the accompanied optimization of rate-limiting enzymes, metabolic flux, and product toxicity tolerance. We suggest further studies to focus on the development of systematical, integrational, and synthetic biological strategies in light of the inter disciplines at the cutting edge. Our review provides insights into the current advances of monoterpene bioengineering and serves as a reference for future studies to promote the industrial production of valuable monoterpenes.
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14
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Zeng H, Yang A. Quantification of proteomic and metabolic burdens predicts growth retardation and overflow metabolism in recombinant Escherichia coli. Biotechnol Bioeng 2019; 116:1484-1495. [PMID: 30712260 DOI: 10.1002/bit.26943] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/17/2018] [Accepted: 01/31/2019] [Indexed: 02/06/2023]
Abstract
Escherichia coli has been the host organism most frequently investigated for efficient recombinant protein production. However, the production of a foreign protein in recombinant E. coli often leads to growth deterioration and elevated secretion of acetic acid. Such observed phenomena have been widely linked with cell stress responses and metabolic burdens originated particularly from the increased energy demand. In this study, flux balance analysis and dynamic flux balance analysis were applied to investigate the observed growth physiology of recombinant E. coli, incorporating the proteome allocation theory and an adjustable maintenance energy level (ATPM) to capture the proteomic and energetic burdens introduced by recombinant protein synthesis. Model predictions of biomass growth, substrate consumption, acetate excretion, and protein production with two different strains were in good agreement with the experimental data, indicating that the constraint on the available proteomic resource and the change in ATPM might be important contributors governing the growth physiology of recombinant strains. The modeling framework developed in this work, currently with several limitations to overcome, offers a starting point for the development of a practical, model-based tool to guide metabolic engineering decisions for boosting recombinant protein production.
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Affiliation(s)
- Hong Zeng
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Aidong Yang
- Department of Engineering Science, University of Oxford, Oxford, UK
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15
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Xiang Y, Dalchau N, Wang B. Scaling up genetic circuit design for cellular computing: advances and prospects. NATURAL COMPUTING 2018; 17:833-853. [PMID: 30524216 PMCID: PMC6244767 DOI: 10.1007/s11047-018-9715-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Synthetic biology aims to engineer and redesign biological systems for useful real-world applications in biomanufacturing, biosensing and biotherapy following a typical design-build-test cycle. Inspired from computer science and electronics, synthetic gene circuits have been designed to exhibit control over the flow of information in biological systems. Two types are Boolean logic inspired TRUE or FALSE digital logic and graded analog computation. Key principles for gene circuit engineering include modularity, orthogonality, predictability and reliability. Initial circuits in the field were small and hampered by a lack of modular and orthogonal components, however in recent years the library of available parts has increased vastly. New tools for high throughput DNA assembly and characterization have been developed enabling rapid prototyping, systematic in situ characterization, as well as automated design and assembly of circuits. Recently implemented computing paradigms in circuit memory and distributed computing using cell consortia will also be discussed. Finally, we will examine existing challenges in building predictable large-scale circuits including modularity, context dependency and metabolic burden as well as tools and methods used to resolve them. These new trends and techniques have the potential to accelerate design of larger gene circuits and result in an increase in our basic understanding of circuit and host behaviour.
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Affiliation(s)
- Yiyu Xiang
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3JR UK
| | | | - Baojun Wang
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3JR UK
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16
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Alba-Martínez Z, Ramírez-Silva L, Hernández-Alcántara G. Exploring the differences between the three pyruvate kinase isozymes from Vibrio cholerae in a heterologous expression system. BMC Res Notes 2018; 11:527. [PMID: 30064476 PMCID: PMC6069732 DOI: 10.1186/s13104-018-3651-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/25/2018] [Indexed: 11/17/2022] Open
Abstract
Objective The genome of Vibrio cholerae has three paralog genes encoding for distinct pyruvate kinases. We were interested in elucidating whether they were expressed, and contributed to the pyruvate kinase activity of V. cholerae. VcIPK and VcIIPK were transformed and expressed in BL21-CodonPlus(DE3)-RIL strain, whereas VcIIIPK could not be transformed. Those studied did contribute to the pyruvate kinase activity of the bacteria. Therefore, our aim was to find an efficient transformation and commonly used over-expression heterologous system for VcIIIPK and develop its purification protocol. Results vcIpk, vcIIpk and vcIIIpk genes were transformed in six different BL21 expression strains. No transformants were obtained for the vcIIIpk gene using BL21(DE3), BL21(DE3)pLysS and BL21(DE3)CodonPlus-RIL strains. Reduced rates of cell growth were observed for BL21-Gold(DE3)pLysS and Origami B(DE3)pLysS. High efficiency of transformation was obtained for BL21-AI. Using this strain, VcIIIPK was purified but proved to be unstable during its purification and storage. Therefore, the transformation of vcIIIpk gene resulted in a toxic, mildly toxic or nontoxic product for these BL21 strains. Despite VcIIPK and VcIIIPK being phylogenetically related, the preservation of the proteins is drastically different; whereas one is preserved during purification and storage, the other is auto-proteolyzed completely in less than a week. Electronic supplementary material The online version of this article (10.1186/s13104-018-3651-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zoe Alba-Martínez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Leticia Ramírez-Silva
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Gloria Hernández-Alcántara
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico.
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17
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Ihling N, Bittner N, Diederichs S, Schelden M, Korona A, Höfler GT, Fulton A, Jaeger KE, Honda K, Ohtake H, Büchs J. Online measurement of the respiratory activity in shake flasks enables the identification of cultivation phases and patterns indicating recombinant protein production in various Escherichia coli host strains. Biotechnol Prog 2018; 34:315-327. [PMID: 29314728 DOI: 10.1002/btpr.2600] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 12/12/2017] [Indexed: 12/21/2022]
Abstract
Escherichia coli is commonly used for recombinant protein production with many available host strains. Screening experiments are often performed in batch mode using shake flasks and evaluating only the final product concentration. This conventional approach carries the risk of missing the best strain due to limited monitoring capabilities. Thus, this study focuses on investigating the general suitability of online respiration measurement for selecting expression hosts for heterologous protein production. The oxygen transfer rate (OTR) for different T7-RNA polymerase-dependent Escherichia coli expression strains was compared under inducing and noninducing conditions. As model enzymes, a lipase A from Bacillus subtilis (BSLA) and a 3-hydroxybutyryl-CoA dehydrogenase from Thermus thermophilus (HBD) were chosen. Four strains were compared during expression of both enzymes in autoinduction medium. Additionally, four strains were compared during expression of the BSLA with IPTG induction. It was found that the metabolic burden during recombinant protein production induces a phase of constant OTR, while undisturbed cell growth with no or little product formation is indicated by an exponential increase. This pattern is independent of the host strain, expressed enzyme, and induction method. Furthermore, the OTR gives information about carbon source consumption, biomass formation, and the transition from production to noninduced second growth phase, thereby ensuring a fair comparison of different strains. In conclusion, online monitoring of the respiration activity is suited to qualitatively identify, if a recombinant protein is produced by a strain or not. Furthermore, laborious offline sampling is avoided. Thus, the technique is easier and faster compared to conventional approaches. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:315-327, 2018.
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Affiliation(s)
- Nina Ihling
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany.,Bioeconomy Science Center (BioSC), Jülich, Germany
| | - Natalie Bittner
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany
| | - Sylvia Diederichs
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany
| | - Maximilian Schelden
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany.,Bioeconomy Science Center (BioSC), Jülich, Germany
| | - Anna Korona
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany
| | - Georg Theo Höfler
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany
| | - Alexander Fulton
- Institute of Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Forschungszentrum Jülich, Jülich D-52426, Germany
| | - Karl-Erich Jaeger
- Bioeconomy Science Center (BioSC), Jülich, Germany.,Institute of Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Forschungszentrum Jülich, Jülich D-52426, Germany.,Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich D-52426, Germany
| | - Kohsuke Honda
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hisao Ohtake
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen D-52074, Germany.,Bioeconomy Science Center (BioSC), Jülich, Germany
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18
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Mühlmann M, Forsten E, Noack S, Büchs J. Optimizing recombinant protein expression via automated induction profiling in microtiter plates at different temperatures. Microb Cell Fact 2017; 16:220. [PMID: 29183374 PMCID: PMC5706349 DOI: 10.1186/s12934-017-0832-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/21/2017] [Indexed: 02/06/2023] Open
Abstract
Background Escherichia coli (E. coli) is the most abundant expression host for recombinant proteins. The production efficiency is dependent on a multitude of parameters. Therefore, high-throughput applications have become an increasingly frequent technique to investigate the main factors. Within this study, the effects of temperature, induction time and inducer concentration on the metabolic state and the product formation were extensively examined. Induction profiling of E. coli Tuner(DE3) pRhotHi-2-EcFbFP was performed in 48-well Flowerplates and standard 96-well plates using a robotic platform. In parallel shake flask cultivations, the respiration activity of the microorganisms was analyzed. Therefore, two online-monitoring systems were applied: the BioLector for microtiter plates and the RAMOS-device for shake flasks. The impact of different induction conditions on biomass and product formation as well as on the oxygen transfer rate was surveyed. Results Different optimal induction conditions were obtained for temperatures of 28, 30, 34, and 37 °C. The best inducer concentrations were determined to be between 0.05 and 0.1 mM IPTG for all investigated temperatures. This is 10–20 times lower than conventional guidelines suggest. The induction time was less relevant when the correct inducer concentration was chosen. Furthermore, there was a stronger impact on growth and respiration activity at higher temperatures. This indicated a higher metabolic burden. Therefore, lower IPTG concentrations were advantageous at elevated temperatures. Very similar results were obtained in standard 96-well plates. Conclusion Two online-monitoring systems were successfully used to investigate the optimal induction conditions for the E. coli Tuner(DE3) pRhotHi-2-EcFbFP strain (lacY deletion mutant) at four different temperatures. The experimental effort was reduced to a minimum by integrating a liquid handling robot. To reach the maximum product formation, a detailed induction analysis was necessary. Whenever the cultivation temperature was changed, the induction conditions have to be adapted. Due to the experimental options provided by the BioLector technology, it was found that the higher the cultivation temperature, the lower the inducer concentration that has to be applied. Electronic supplementary material The online version of this article (10.1186/s12934-017-0832-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martina Mühlmann
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Eva Forsten
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Saskia Noack
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Jochen Büchs
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany.
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19
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Jian X, Li N, Chen Q, Hua Q. Model-guided identification of novel gene amplification targets for improving succinate production in Escherichia coli NZN111. Integr Biol (Camb) 2017; 9:830-835. [PMID: 28884171 DOI: 10.1039/c7ib00077d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Reconstruction and application of genome-scale metabolic models (GEMs) have facilitated metabolic engineering by providing a platform on which systematic computational analysis of metabolic networks can be performed. In this study, a GEM of Escherichia coli NZN111 was employed by the analysis of production and growth coupling (APGC) algorithm to identify genetic strategies for the overproduction of succinate. Through in silico simulation and reaction expression analysis, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase (PGK), triosephosphate isomerase (TPI), and phosphoenolpyruvate carboxylase (PPC), encoded by gapA, pgk, tpiA, and ppc, respectively, were selected for experimental overexpression. The results showed that overexpressing any of these could improve both growth and succinate production. Specifically, overexpression of GAPDH or PGK showed a significant effect with up to 24% increase in succinate production. These results indicate that the APGC algorithm can be effectively used to guide genetic manipulation for strain design by identifying genome-wide gene amplification targets.
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Affiliation(s)
- Xingxing Jian
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
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20
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Li Z, Nimtz M, Rinas U. Global proteome response of Escherichia coli BL21 to production of human basic fibroblast growth factor in complex and defined medium. Eng Life Sci 2017; 17:881-891. [PMID: 32624836 DOI: 10.1002/elsc.201700036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/15/2017] [Accepted: 05/29/2017] [Indexed: 12/20/2022] Open
Abstract
The global proteome response toward recombinant protein production in Escherichia coli BL21 (DE3) grown in complex and defined medium was analyzed. Overproduction of human basic fibroblast growth factor (hFGF-2), a difficult-to-fold protein, led to a reconstruction of the bacterial proteome. For example, heat shock chaperones were highly upregulated, especially when production occurred during fast growth in complex medium. Although heat shock chaperones increased to higher levels in complex medium more hFGF-2 accumulated within inclusion bodies indicating that the capacity to chaperone protein folding was not sufficient for high speed production. In both types of media, cellular proteins from substrate transport systems, central metabolic pathways, and by-product uptake (e.g. acetate) were downregulated. This downregulation was connected to growth inhibition and metabolic perturbations. For example, during production in complex and defined medium acetate reassimilation and glucose uptake, respectively, were severely hampered. Cellular proteins for degradation of less favorable substrates, elimination of reactive oxygen species, and DNA protection were also downregulated in response to hFGF-2 production. The decrease of proteins involved in transport, central metabolic pathways, and general cell protection was more pronounced in the fast producing culture in complex medium than in the slow producing culture in defined medium. In general, production of hFGF-2 seems to interfere with the adaptation process to changing growth conditions, in this case the adaptation from exponential growth to stationary phase.
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Affiliation(s)
- Zhaopeng Li
- Technical Chemistry - Life Science Leibniz University of Hannover Hannover Germany
| | - Manfred Nimtz
- Helmholtz Centre for Infection Research Braunschweig Germany
| | - Ursula Rinas
- Technical Chemistry - Life Science Leibniz University of Hannover Hannover Germany.,Helmholtz Centre for Infection Research Braunschweig Germany
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21
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Rahmen N, Schlupp CD, Mitsunaga H, Fulton A, Aryani T, Esch L, Schaffrath U, Fukuzaki E, Jaeger KE, Büchs J. A particular silent codon exchange in a recombinant gene greatly influences host cell metabolic activity. Microb Cell Fact 2015; 14:156. [PMID: 26438243 PMCID: PMC4595056 DOI: 10.1186/s12934-015-0348-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/28/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recombinant protein production using Escherichia coli as expression host is highly efficient, however, it also induces strong host cell metabolic burden. Energy and biomass precursors are withdrawn from the host's metabolism as they are required for plasmid replication, heterologous gene expression and protein production. Rare codons in a heterologous gene may be a further drawback. This study aims to investigate the influence of particular silent codon exchanges within a heterologous gene on host cell metabolic activity. Silent mutations were introduced into the coding sequence of a model protein to introduce all synonymous arginine or leucine codons at two randomly defined positions, as well as substitutions leading to identical amino acid exchanges with different synonymous codons. The respective E. coli clones were compared during cultivation in a mineral autoinduction medium using specialized online and offline measuring techniques to quantitatively analyze effects on respiration, biomass and protein production, as well as on carbon source consumption, plasmid copy number, intracellular nucleobases and mRNA content of each clone. RESULTS Host stain metabolic burden correlates with recombinant protein production. Upon heterologous gene expression, tremendous differences in respiration, biomass and protein production were observed. According to their different respiration activity the E. coli clones could be classified into two groups, Type A and Type B. Type A clones tended to higher product formation, Type B clones showed stronger biomass formation. Whereas codon usage and intracellular nucleobases had no influence on the Type-A-Type-B-behavior, plasmid copy number, mRNA content and carbon source consumption strongly differed between the two groups. CONCLUSIONS Particular silent codon exchanges in a heterologous gene sequence led to differences in initial growth of Type A and Type B clones. Thus, the biomass concentration at the time point of induction varied. In consequence, not only plasmid copy number and expression levels differed between the two groups, but also the kinetics of lactose and glycerol consumption. Even though the underlying molecular mechanisms are not yet identified we observed the astonishing phenomenon that particular silent codon exchanges within a heterologous gene tremendously affect host cell metabolism and recombinant protein production. This could have great impact on codon optimization of heterologous genes, screening procedures for improved variants, and biotechnological protein production processes.
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Affiliation(s)
- Natalie Rahmen
- AVT, Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
| | - Christian D Schlupp
- Department of Plant Physiology, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.
| | - Hitoshi Mitsunaga
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, 565-0871, Japan.
| | - Alexander Fulton
- Institute for Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Forschungszentrum Jülich, 52426, Jülich, Germany.
| | - Tita Aryani
- AVT, Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
| | - Lara Esch
- Department of Plant Physiology, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.
| | - Ulrich Schaffrath
- Department of Plant Physiology, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.
| | - Eiichiro Fukuzaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, 565-0871, Japan.
| | - Karl-Erich Jaeger
- Institute for Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Forschungszentrum Jülich, 52426, Jülich, Germany. .,Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52426, Jülich, Germany.
| | - Jochen Büchs
- AVT, Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
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Theodosiou E, Frick O, Bühler B, Schmid A. Metabolic network capacity of Escherichia coli for Krebs cycle-dependent proline hydroxylation. Microb Cell Fact 2015. [PMID: 26215086 PMCID: PMC4517350 DOI: 10.1186/s12934-015-0298-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Background Understanding the metabolism of the microbial host is essential for the development and optimization of whole-cell based biocatalytic processes, as it dictates production efficiency. This is especially true for redox biocatalysis where metabolically active cells are employed because of the cofactor/cosubstrate regenerative capacity endogenous in the host. Recombinant Escherichia coli was used for overproducing proline-4-hydroxylase (P4H), a dioxygenase catalyzing the hydroxylation of free l-proline into trans-4-hydroxy-l-proline with a-ketoglutarate (a-KG) as cosubstrate. In this whole-cell biocatalyst, central carbon metabolism provides the required cosubstrate a-KG, coupling P4H biocatalytic performance directly to carbon metabolism and metabolic activity. By applying both experimental and computational biology tools, such as metabolic engineering and 13C-metabolic flux analysis (13C-MFA), we investigated and quantitatively described the physiological, metabolic, and bioenergetic response of the whole-cell biocatalyst to the targeted bioconversion and identified possible metabolic bottlenecks for further rational pathway engineering. Results A proline degradation-deficient E. coli strain was constructed by deleting the putA gene encoding proline dehydrogenase. Whole-cell biotransformations with this mutant strain led not only to quantitative proline hydroxylation but also to a doubling of the specific trans-4-l-hydroxyproline (hyp) formation rate, compared to the wild type. Analysis of carbon flux through central metabolism of the mutant strain revealed that the increased a-KG demand for P4H activity did not enhance the a-KG generating flux, indicating a tightly regulated TCA cycle operation under the conditions studied. In the wild type strain, P4H synthesis and catalysis caused a reduction in biomass yield. Interestingly, the ΔputA strain additionally compensated the associated ATP and NADH loss by reducing maintenance energy demands at comparably low glucose uptake rates, instead of increasing the TCA activity. Conclusions The putA knockout in recombinant E. coli BL21(DE3)(pLysS) was found to be promising for productive P4H catalysis not only in terms of biotransformation yield, but also regarding the rates for biotransformation and proline uptake and the yield of hyp on the energy source. The results indicate that, upon a putA knockout, the coupling of the TCA-cycle to proline hydroxylation via the cosubstrate a-KG becomes a key factor constraining and a target to further improve the efficiency of a-KG-dependent biotransformations. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0298-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eleni Theodosiou
- Department of Biochemical and Chemical Engineering, Laboratory of Chemical Biotechnology, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany. .,Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany.
| | - Oliver Frick
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany.
| | - Bruno Bühler
- Department of Biochemical and Chemical Engineering, Laboratory of Chemical Biotechnology, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany. .,Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany.
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany.
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Rahmen N, Fulton A, Ihling N, Magni M, Jaeger KE, Büchs J. Exchange of single amino acids at different positions of a recombinant protein affects metabolic burden in Escherichia coli. Microb Cell Fact 2015; 14:10. [PMID: 25612616 PMCID: PMC4307990 DOI: 10.1186/s12934-015-0191-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 01/05/2015] [Indexed: 12/19/2022] Open
Abstract
Background Escherichia coli is commonly used in academia and industry for expressing recombinant proteins because of its well-characterized molecular genetics and the availability of numerous expression vectors and strains. One important issue during recombinant protein production is the so-called ‘metabolic burden’: the material and energy normally reserved for microbial metabolism which is sapped from the bacterium to produce the recombinant protein. This material and energy drain harms biomass formation and modifies respiration. To the best of our knowledge, no research has investigated so far whether a single amino acid exchange in a recombinant protein affects the metabolic burden phenomenon. Thus, in this study, 15 E. coli BL21(DE3) clones expressing either the fusion tags, a recombinant wild type lipase, or 13 different lipase variants are investigated to quantitatively analyze the respective effects of single amino acid exchanges at different positions on respiration, biomass and protein production of each clone. Therefore, two small-scale online monitoring systems, namely a Respiration Activity MOnitoring System (RAMOS) and a microtiter plate based cultivation system (BioLector) are applied. Results Upon expression of all enzyme variants, strong variations were found in the Oxygen Transfer Rate (OTR), biomass and protein (lipase) production of the respective E. coli clones. Two distinct patterns of respiration behavior were observed and, so, the clones could be classified into two groups (Type A and B). Potential factors to explain these patterns were evaluated (e.g. plasmid copy number, inclusion body formation). However, no decisive factor could yet be identified. Five distinct cultivation phases could be determined from OTR curves which give real-time information about carbon source consumption, biomass and protein production. In general, it was found that the quantity of product increased with the duration of active respiration. Conclusions This work demonstrates that single amino acid exchanges in a recombinant protein influence the metabolic burden during protein production. The small-scale online monitoring devices RAMOS and BioLector enable the real-time detection of even smallest differences in respiration behavior, biomass and protein production in the E. coli clones investigated. Hence, this study underscores the importance of parallel online monitoring systems to unveil the relevance of single amino acid exchanges for the recombinant protein production. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0191-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natalie Rahmen
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
| | - Alexander Fulton
- Institute for Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Forschungszentrum Jülich, D-52426, Jülich, Germany.
| | - Nina Ihling
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
| | - Marzio Magni
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
| | - Karl-Erich Jaeger
- Institute for Molecular Enzyme Technology, Heinrich-Heine-University Düsseldorf, Forschungszentrum Jülich, D-52426, Jülich, Germany. .,Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D-52426, Jülich, Germany.
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
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Diederichs S, Korona A, Staaden A, Kroutil W, Honda K, Ohtake H, Büchs J. Phenotyping the quality of complex medium components by simple online-monitored shake flask experiments. Microb Cell Fact 2014; 13:149. [PMID: 25376163 PMCID: PMC4230760 DOI: 10.1186/s12934-014-0149-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/15/2014] [Indexed: 11/10/2022] Open
Abstract
Background Media containing yeast extracts and other complex raw materials are widely used for the cultivation of microorganisms. However, variations in the specific nutrient composition can occur, due to differences in the complex raw material ingredients and in the production of these components. These lot-to-lot variations can affect growth rate, product yield and product quality in laboratory investigations and biopharmaceutical production processes. In the FDA’s Process Analytical Technology (PAT) initiative, the control and assessment of the quality of critical raw materials is one key aspect to maintain product quality and consistency. In this study, the Respiration Activity Monitoring System (RAMOS) was used to evaluate the impact of different yeast extracts and commercial complex auto-induction medium lots on metabolic activity and product yield of four recombinant Escherichia coli variants encoding different enzymes. Results Under non-induced conditions, the oxygen transfer rate (OTR) of E. coli was not affected by a variation of the supplemented yeast extract lot. The comparison of E. coli cultivations under induced conditions exhibited tremendous differences in OTR profiles and volumetric activity for all investigated yeast extract lots of different suppliers as well as lots of the same supplier independent of the E. coli variant. Cultivation in the commercial auto-induction medium lots revealed the same reproducible variations. In cultivations with parallel offline analysis, the highest volumetric activity was found at different cultivation times. Only by online monitoring of the cultures, a distinct cultivation phase (e.g. glycerol depletion) could be detected and chosen for comparable and reproducible offline analysis of the yield of functional product. Conclusions This work proves that cultivations conducted in complex media may be prone to significant variation in final product quality and quantity if the quality of the raw material for medium preparation is not thoroughly checked. In this study, the RAMOS technique enabled a reliable and reproducible screening and phenotyping of complex raw material lots by online measurement of the respiration activity. Consequently, complex raw material lots can efficiently be assessed if the distinct effects on culture behavior and final product quality and quantity are visualized. Electronic supplementary material The online version of this article (doi:10.1186/s12934-014-0149-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sylvia Diederichs
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
| | - Anna Korona
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
| | - Antje Staaden
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
| | - Wolfgang Kroutil
- Department of Chemistry, Organic and Bioorganic Chemistry, NAWI Graz, University of Graz, Heinrichstrasse 28, A-8010, Graz, Austria.
| | - Kohsuke Honda
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Hisao Ohtake
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Worringerweg 1, D-52074, Aachen, Germany.
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Kunze M, Roth S, Gartz E, Büchs J. Pitfalls in optical on-line monitoring for high-throughput screening of microbial systems. Microb Cell Fact 2014; 13:53. [PMID: 24725602 PMCID: PMC4012768 DOI: 10.1186/1475-2859-13-53] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/03/2014] [Indexed: 11/16/2022] Open
Abstract
Background New high-throughput screening systems for microbial systems, e.g. the BioLector technology, are simple to handle and offer various options of optical online measurements. The parallelization and small scale in microtiter plates allow economical high throughput and, hence, to screen many parameters in reasonable time. Fluorescent proteins as fluorescent tags made the tracking of cellular proteins in-vivo a routine task. All these tools significantly contribute to the understanding of bioprocesses. But, there are some pitfalls which might mislead the user of such techniques. Results In this work the bacterium E. coli and the yeast K. lactis expressing the recombinant fluorescent proteins GFP, YFP, FbFP and mCherry were investigated. Cultivations were performed applying special microtiter plates with optodes for dissolved oxygen tension (DOT) and pH measurement in the BioLector system. In this way, microbial growth, protein formation, DOT and pH were monitored on-line via optical signals. During these studies it became obvious that fluorescent proteins can interfere with the optical signals leading to incorrect results. In this work these effects are characterized in detail and possibilities are presented how such adverse effects can be corrected or minimized by mathematical procedures or modification of the measuring method. Additionally, it is shown that morphological changes of cells can affect the biomass on-line monitoring via scattered light. Conclusions The here reported phenomena refer to typical experiments in biotechnological labs. For this reason these aspects are highlighted in this work to make operators of such valuable techniques as the BioLector aware for potential pitfalls and resulting misinterpretations. With the right approach it is possible to minimize existing problems and deal with them.
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Affiliation(s)
| | | | | | - Jochen Büchs
- AVT-Chair for Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
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Baek JM, Mazumdar S, Lee SW, Jung MY, Lim JH, Seo SW, Jung GY, Oh MK. Butyrate production in engineered Escherichia coli with synthetic scaffolds. Biotechnol Bioeng 2013; 110:2790-4. [PMID: 23568786 DOI: 10.1002/bit.24925] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 02/04/2023]
Abstract
Butyrate pathway was constructed in recombinant Escherichia coli using the genes from Clostridium acetobutylicum and Treponema denticola. However, the pathway constructed from exogenous enzymes did not efficiently convert carbon flux to butyrate. Three steps of the productivity enhancement were attempted in this study. First, pathway engineering to delete metabolic pathways to by-products successfully improved the butyrate production. Second, synthetic scaffold protein that spatially co-localizes enzymes was introduced to improve the efficiency of the heterologous pathway enzymes, resulting in threefold improvement in butyrate production. Finally, further optimizations of inducer concentrations and pH adjustment were tried. The final titer of butyrate was 4.3 and 7.2 g/L under batch and fed-batch cultivation, respectively. This study demonstrated the importance of synthetic scaffold protein as a useful tool for optimization of heterologous butyrate pathway in E. coli.
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Affiliation(s)
- Jang-Mi Baek
- Department of Chemical and Biological Engineering, Korea University, Sungbuk-Gu, Seoul 136-713, South Korea
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Kunze M, Huber R, Gutjahr C, Müllner S, Büchs J. Predictive tool for recombinant protein production in Escherichia coli Shake-Flask cultures using an on-line monitoring system. Biotechnol Prog 2011; 28:103-13. [DOI: 10.1002/btpr.719] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 08/18/2011] [Indexed: 12/20/2022]
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Engineering yield and rate of reductive biotransformation in Escherichia coli by partial cyclization of the pentose phosphate pathway and PTS-independent glucose transport. Appl Microbiol Biotechnol 2011; 93:1459-67. [PMID: 22002070 PMCID: PMC3275745 DOI: 10.1007/s00253-011-3626-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/12/2011] [Accepted: 09/30/2011] [Indexed: 10/27/2022]
Abstract
Optimization of yields and productivities in reductive whole-cell biotransformations is an important issue for the industrial application of such processes. In a recent study with Escherichia coli, we analyzed the reduction of the prochiral β-ketoester methyl acetoacetate by an R-specific alcohol dehydrogenase (ADH) to the chiral hydroxy ester (R)-methyl 3-hydroxybutyrate (MHB) using glucose as substrate for the generation of NADPH. Deletion of the phosphofructokinase gene pfkA almost doubled the yield to 4.8 mol MHB per mole of glucose, and it was assumed that this effect was due to a partial cyclization of the pentose phosphate pathway (PPP). Here, this partial cyclization was confirmed by (13)C metabolic flux analysis, which revealed a negative net flux from glucose 6-phosphate to fructose 6-phosphate catalyzed by phosphoglucose isomerase. For further process optimization, the genes encoding the glucose facilitator (glf) and glucokinase (glk) of Zymomonas mobilis were overexpressed in recombinant E. coli strains carrying ADH and deletions of either pgi (phosphoglucose isomerase), or pfkA, or pfkA plus pfkB. In all cases, the glucose uptake rate was increased (30-47%), and for strains Δpgi and ΔpfkA also, the specific MHB production rate was increased by 15% and 20%, respectively. The yield of the latter two strains slightly dropped by 11% and 6%, but was still 73% and 132% higher compared to the reference strain with intact pgi and pfkA genes and expressing glf and glk. Thus, metabolic engineering strategies are presented for improving yield and rate of reductive redox biocatalysis by partial cyclization of the PPP and by increasing glucose uptake, respectively.
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Popov M, Petrov S, Nacheva G, Ivanov I, Reichl U. Effects of a recombinant gene expression on ColE1-like plasmid segregation in Escherichia coli. BMC Biotechnol 2011; 11:18. [PMID: 21362179 PMCID: PMC3061898 DOI: 10.1186/1472-6750-11-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 03/01/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Segregation of expression plasmids leads to loss of recombinant DNA from transformed bacterial cells due to the irregular distribution of plasmids between the daughter cells during cell division. Under non-selective conditions this segregational instability results in a heterogeneous population of cells, where the non-productive plasmid-free cells overgrow the plasmid-bearing cells thus decreasing the yield of recombinant protein. Amongst the factors affecting segregational plasmid instability are: the plasmid design, plasmid copy-number, host cell genotype, fermentation conditions etc. This study aims to investigate the influence of transcription and translation on the segregation of recombinant plasmids designed for constitutive gene expression in Escherichia coli LE392 at glucose-limited continuous cultivation. To this end a series of pBR322-based plasmids carrying a synthetic human interferon-gamma (hIFNγ) gene placed under the control of different regulatory elements (promoter and ribosome-binding sites) were used as a model. RESULTS Bacterial growth and product formation kinetics of transformed E. coli LE392 cells cultivated continuously were described by a structured kinetic model proposed by Lee et al. (1985). The obtained results demonstrated that both transcription and translation efficiency strongly affected plasmid segregation. The segregation of plasmid having a deleted promoter did not exceed 5% after 190 h of cultivation. The observed high plasmid stability was not related with an increase in the plasmid copy-number. A reverse correlation between the yield of recombinant protein (as modulated by using different ribosome binding sites) and segregational plasmid stability (determined by the above model) was also observed. CONCLUSIONS Switching-off transcription of the hIFNγ gene has a stabilising effect on ColE1-like plasmids against segregation, which is not associated with an increase in the plasmid copy-number. The increased constitutive gene expression has a negative effect on segregational plasmid stability. A kinetic model proposed by Lee et al. (1985) was appropriate for description of E. coli cell growth and recombinant product formation in chemostat cultivations.
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Affiliation(s)
- Mladen Popov
- Institute of Molecular Biology Roumen Tsanev, Bulgarian Academy of Sciences, Acad, G, Bonchev Str,, 21, 1113 Sofia, Bulgaria.
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Sommer C, Volk N, Pietzsch M. Model based optimization of the fed-batch production of a highly active transglutaminase variant in Escherichia coli. Protein Expr Purif 2010; 77:9-19. [PMID: 21168505 DOI: 10.1016/j.pep.2010.12.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/06/2010] [Accepted: 12/13/2010] [Indexed: 11/18/2022]
Abstract
A process for the production of a thermostable variant of a microbial transglutaminase was developed. The transglutaminase variant produced, carried a single amino acid exchange (serine replaced by proline at position 2) and showed a nearly doubled specific activity of 46.1 Umg(-1) compared to the wild-type enzyme. Based on a model based optimization strategy, intracellular soluble production in Escherichia coli was optimized. After parameter identification and only two fed-batch cultivations, a space time yield of 1438 U(TG)L(-1)h(-1) was obtained which is 175% higher than the highest values published so far (extracellular production using Corynebacterium ammoniagenes). High carbon source concentrations during expression were found to increase the product formation. Prior to the fed-batch cultivation, the host strain was adapted from complex medium to minimal medium by serial dilution. Upon transfer to the minimal medium, initially the maximal growth rate dropped to 0.13 h(-1). After the six consecutive cultivations the rate increased to 0.47 h(-1) and the portion of the complex medium was reduced to 1 ppm. Using the adapted cells, temperature after induction and IPTG-concentration were investigated by satellite batch cultivation according to a Design of Experiment (DoE) plan. The product yield was strongly influenced by the temperature after induction but not by the inductor concentration. The highest specific activity of 1386 Ug(-1) bio dry mass was obtained at 29°C and 0.7 mM IPTG.
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Affiliation(s)
- Christian Sommer
- Department of Downstream Processing, Institute of Pharmacy, Faculty of Sciences I, Martin Luther University Halle-Wittenberg, 06099 Halle, Saale, Germany
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31
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Maervoet VET, De Mey M, Beauprez J, De Maeseneire S, Soetaert WK. Enhancing the Microbial Conversion of Glycerol to 1,3-Propanediol Using Metabolic Engineering. Org Process Res Dev 2010. [DOI: 10.1021/op1001929] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Veerle E. T. Maervoet
- Centre of Expertise - Industrial Biotechnology and Biocatalysis, Department of Biochemical and Microbial Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Marjan De Mey
- Centre of Expertise - Industrial Biotechnology and Biocatalysis, Department of Biochemical and Microbial Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Joeri Beauprez
- Centre of Expertise - Industrial Biotechnology and Biocatalysis, Department of Biochemical and Microbial Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Sofie De Maeseneire
- Centre of Expertise - Industrial Biotechnology and Biocatalysis, Department of Biochemical and Microbial Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Wim K. Soetaert
- Centre of Expertise - Industrial Biotechnology and Biocatalysis, Department of Biochemical and Microbial Technology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
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Selective expression of the soluble product fraction in Escherichia coli cultures employed in recombinant protein production processes. Appl Microbiol Biotechnol 2010; 87:2047-58. [DOI: 10.1007/s00253-010-2608-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 03/31/2010] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
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Balagadde FK. The new role of the microchemostat in the bioengineering revolution. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:1064-6. [PMID: 19965138 DOI: 10.1109/iembs.2009.5335037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Since the inception of synthetic biology as a discipline, bioengineers have used the electronic circuit paradigm to analyze, model, simulate and interpret the behavior of genetic circuits. In this paper, we elaborate upon the effect of evolution as an overriding attribute of the biological systems, which makes genetic circuits inherently fickle compared to their electronic counterparts. Shrinking the volume of programmed microbial population reduces the effects of evolution. This concept was demonstrated by characterizing the dynamics of Escherichia coli cells carrying a synthetic "population control" circuit, which regulates cell density through a feedback mechanism based on quorum sensing. The microchemostat prolonged the lifetime of the programmed circuit by at least an order of magnitude compared macro-scale characterization schemes.
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Ow DSW, Lee DY, Yap MGS, Oh SKW. Identification of cellular objective for elucidating the physiological state of plasmid-bearing Escherichia coli using genome-scale in silico analysis. Biotechnol Prog 2009; 25:61-7. [PMID: 19224555 DOI: 10.1002/btpr.51] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The presence of multiple copies of plasmids in Escherichia coli could induce a complex cascade of physiological changes known as the metabolic burden response. In this work, the physiological effect of such plasmid metabolic burden on E. coli metabolism was investigated by constraint-based genome-scale flux modeling. We systematically applied three cellular objectives: (a) maximizing growth rate, (b) maximizing plasmid production, and (c) maximizing maintenance energy expenditure to quantify in silico flux distributions. These simulated results were compared with experimental flux information to identify which of these cellular objectives best describes the physiological and metabolic states of plasmid-bearing (P+) E. coli. Unlike the wild-type E. coli cells that have directed the metabolism toward an optimum growth rate under the nutrient-limited condition, the maximum growth rate objective could not correctly predict the metabolic state of recombinant P+ cells. Instead, flux simulations by maximizing maintenance energy expenditure showed good consistency with experimental observation, indicating that the P+ cells are energetically less efficient and could require higher maintenance energy. This study demonstrates that the cellular objective of maximizing maintenance energy expenditure provides a better description of the underlying physiological state in recombinant microorganisms relevant to biotechnological applications.
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Affiliation(s)
- Dave Siak-Wei Ow
- Bioprocessing Technology Institute, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138668
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35
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Development of a fed-batch process for the production of anticancer drug TATm-survivin(T34A) in Escherichia coli. Biochem Eng J 2009. [DOI: 10.1016/j.bej.2008.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Mirmomeni MH, Colagar AH, Ghazaey S. Molecular study of Salmonella enteritidis in poultry samples by PCR, plasmid curing, antibiotic resistance and protein pattern analysis. Pak J Biol Sci 2009; 10:1562-70. [PMID: 19086500 DOI: 10.3923/pjbs.2007.1562.1570] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study two control isolates of Salmonella enteritidis, RTCC1623 and RTCC1624, were obtained from the institute ofRazi (Karaj-Iran) and 14 strains were isolated from poultry samples in Kermanshah province of Iran, according to a standard protocol. These isolates were confirmed by PCR amplification of SefA gene fragments. Results showed that, 6 isolates of 14 isolates of Salmonella which their biochemical tests were positive contain 511 bp amplified fragments of the SefA gene. In other purpose, to correlating the presence of plasmids with antibiotic resistance and protein pattern, plasmid DNA was isolated before and after plasmid curing by using the alkaline lysis method. Strains of S. enteritidis contain seven different plasmid profiles (P1-P7) which were characterized by antibiotic resistance and protein pattern. Our observed showed, there was a high molecular weight plasmid with Rf 0.17 in all strains and the frequency of other plasmids was low. The plasmid with Rf about 0.2 is responsible for resistance to Cephalothin and the isolates that lost it were susceptible to this antibiotic. All strains, 100%, were resistant to ampicillin before and after curing of strains. According to present findings, PCR is a rapid and sensitive method for typing of S. enteritidis and plasmid profiling; antibiotic resistance and protein pattern are suitable methods for subtyping of S. enteritidis isolates. No direct correlation was found between plasmid contents, antibiotic resistance patterns and protein profiles of local S. enteritidis isolates.
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Affiliation(s)
- M H Mirmomeni
- Department of Biology, Faculty of Science, Razi University, Kermanshah, Iran
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37
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A new fermentation strategy for S-adenosylmethionine production in recombinant Pichia pastoris. Biochem Eng J 2008. [DOI: 10.1016/j.bej.2008.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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NADH availability limits asymmetric biocatalytic epoxidation in a growing recombinant Escherichia coli strain. Appl Environ Microbiol 2008; 74:1436-46. [PMID: 18192422 DOI: 10.1128/aem.02234-07] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Styrene can efficiently be oxidized to (S)-styrene oxide by recombinant Escherichia coli expressing the styrene monooxygenase genes styAB from Pseudomonas sp. strain VLB120. Targeting microbial physiology during whole-cell redox biocatalysis, we investigated the interdependency of styrene epoxidation, growth, and carbon metabolism on the basis of mass balances obtained from continuous two-liquid-phase cultures. Full induction of styAB expression led to growth inhibition, which could be attenuated by reducing expression levels. Operation at subtoxic substrate and product concentrations and variation of the epoxidation rate via the styrene feed concentration allowed a detailed analysis of carbon metabolism and bioconversion kinetics. Fine-tuned styAB expression and increasing specific epoxidation rates resulted in decreasing biomass yields, increasing specific rates for glucose uptake and the tricarboxylic acid (TCA) cycle, and finally saturation of the TCA cycle and acetate formation. Interestingly, the biocatalysis-related NAD(P)H consumption was 3.2 to 3.7 times higher than expected from the epoxidation stoichiometry. Possible reasons include uncoupling of styrene epoxidation and NADH oxidation and increased maintenance requirements during redox biocatalysis. At epoxidation rates of above 21 micromol per min per g cells (dry weight), the absence of limitations by O(2) and styrene and stagnating NAD(P)H regeneration rates indicated that NADH availability limited styrene epoxidation. During glucose-limited growth, oxygenase catalysis might induce regulatory stress responses, which attenuate excessive glucose catabolism and thus limit NADH regeneration. Optimizing metabolic and/or regulatory networks for efficient redox biocatalysis instead of growth (yield) is likely to be the key for maintaining high oxygenase activities in recombinant E. coli.
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Khasa YP, Khushoo A, Srivastava L, Mukherjee KJ. Kinetic studies of constitutive human granulocyte-macrophage colony stimulating factor (hGM-CSF) expression in continuous culture of Pichia pastoris. Biotechnol Lett 2007; 29:1903-8. [PMID: 17653623 DOI: 10.1007/s10529-007-9473-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 06/29/2007] [Indexed: 10/23/2022]
Abstract
Extracellular human granulocyte-macrophage colony stimulating factor (hGM-CSF) expression was studied under the control of the GAP promoter in recombinant Pichia pastoris in a series of continuous culture runs (dilution rates from 0.025 to 0.2 h(-1)). The inlet feed concentration was also varied and the steady state biomass concentration increased proportionally demonstrating efficient substrate utilization and constancy of the biomass yield coefficient (Y(x/s)) for a given dilution rate. The specific product formation rate (q(P)) showed a strong correlation with dilution rates demonstrating growth associated product formation of hGM-CSF. The volumetric product concentration achieved at the highest feed concentration (4x) and a dilution rate of 0.2 h(-1) was 82 mg l(-1) which was 5-fold higher compared to the continuous culture run with 1x feed concentration at the lowest dilution rate thus translating to a 40 fold increase in the volumetric productivity. The specific product yield (Y(P/X)) increased slightly from 2 to 2.5 mg g(-1), with increasing dilution rates, while it remained fairly invariant, for all feed concentrations demonstrating negligible product degradation or feed back inhibition. The robust nature of this expression system would make it easily amenable to scale up for industrial production.
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Affiliation(s)
- Yogender Pal Khasa
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
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Durany O, Bassett P, Weiss AME, Cranenburgh RM, Ferrer P, López-Santín J, de Mas C, Hanak JAJ. Production of fuculose-1-phosphate aldolase using operator-repressor titration for plasmid maintenance in high cell density Escherichia coli fermentations. Biotechnol Bioeng 2005; 91:460-7. [PMID: 15959893 DOI: 10.1002/bit.20527] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report a novel application for the operator-repressor titration (ORT) plasmid maintenance system. The ability of ORT to maintain a plasmid during production of DNA has been demonstrated previously. In this study, we have used the ORT system to maintain a plasmid during high cell density cultivation and expression of a recombinant protein. No evidence of plasmid loss was seen during protein expression at high cell densities. In addition, the quantity of protein produced using this system was similar to traditional plasmid maintenance systems.
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Affiliation(s)
- Olga Durany
- Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria, Universitat Autònoma de Barcelona, Spain
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Vidal L, Ferrer P, Alvaro G, Benaiges MD, Caminal G. Influence of induction and operation mode on recombinant rhamnulose 1-phosphate aldolase production by Escherichia coli using the T5 promoter. J Biotechnol 2005; 118:75-87. [PMID: 15908029 DOI: 10.1016/j.jbiotec.2005.02.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2004] [Revised: 02/18/2005] [Accepted: 02/25/2005] [Indexed: 11/21/2022]
Abstract
Fed-batch culture techniques were employed to grow Escherichia coli at high-cell densities for the intracellular production of a recombinant rhamnulose 1-phosphate aldolase (RhuA) under the transcriptional control of the strong promoter T5, using a commercially available expression system (E. coli strain M15 and plasmid vector pQE40). A predetermined exponential feeding strategy at constant specific growth rate was selected to maintain carbon source limited growth using a defined medium. Growth rates below 0.36 h(-1) did not cause a severe formation of acetic acid while cell concentration increased exponentially up to 95 g(biomass)l(-1). The intrinsic biomass-substrate yield (gamma(X/S) = 0.48 gg(-1)) and the maintenance coefficient (mS = 0.10 g(substrate)g(biomass)(-1)h(-1)) were calculated from fed-batch growths at different specific growth rates. These values have been employed to determinate the addition profile during the fed-batch growth until IPTG induction, reaching a specific RhuA production levels of 565 AU g(biomass)(-1) which was lower than in batch (1250 AU g(biomass)(-1)). An inverse correlation between volumetric IPTG concentration and specific RhuA activity was found. A correlation between the ratio biomass/OD(600 nm) and the quantity of recombinant protein produced was found. Finally, the proposed process, after optimization of the IPTG concentration, led to significant increase in enzyme concentration and volumetric productivity compared to batch mode (2680 and 1338%, respectively).
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Affiliation(s)
- Luis Vidal
- Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
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Royo JL, Moreno-Ruiz E, Cebolla A, Santero E. Stable long-term indigo production by overexpression of dioxygenase genes using a chromosomal integrated cascade expression circuit. J Biotechnol 2005; 116:113-24. [PMID: 15664075 DOI: 10.1016/j.jbiotec.2004.10.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 10/04/2004] [Accepted: 10/11/2004] [Indexed: 11/17/2022]
Abstract
In our laboratory we have analyzed different factors to maximize the yield in heterologous protein expression for long-term cultivation, by combination of an efficient cascade expression system and stable integration in the bacterial chromosome. In this work, we have explored this system for the production of indigo dye as a model for biotechnological production, by expressing in Escherichia coli the thnA1A2A3A4 genes from Sphingomonas macrogolitabida strain TFA, which encode the components of a tetralin dioxygenase activity. We compared Ptac, and the Pm-based cascade expression circuit in a multicopy plasmid and stably integrated into the bacterial chromosome. Plasmid-based expression systems resulted in instability of indigo production when serially diluted batch experiments were performed without a selective pressure. This problem was solved by integrating the expression module in the chromosome. Despite the gene dosage reduction, the synergic effect of the cascade expression system produced comparable expression to the dioxygenase activity in the plasmid configuration but could be stably maintained for at least 5 days. Here, we show that the cascade amplification circuit integrated in the chromosome could be an excellent system for tight control and stable production of recombinant products.
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Affiliation(s)
- Jose Luis Royo
- Departamento de Ciencias Ambientales, Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Ctra. Utrera Km 1, 41013 Sevilla, Spain
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Vemuri GN, Minning TA, Altman E, Eiteman MA. Physiological response of central metabolism inEscherichia coli to deletion of pyruvate oxidase and introduction of heterologous pyruvate carboxylase. Biotechnol Bioeng 2005; 90:64-76. [PMID: 15736164 DOI: 10.1002/bit.20418] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We studied the physiological response of Escherichia coli central metabolism to the expression of heterologous pyruvate carboxylase (PYC) in the presence and absence of pyruvate oxidase (POX). These studies were complemented with expression analysis of central and intermediary metabolic genes and conventional in vitro enzyme assays to evaluate glucose metabolism at steady-state growth conditions (chemostats). The absence of POX activity reduced nongrowth-related energy metabolism (maintenance coefficient) and increased the maximum specific rate of oxygen consumption. The presence of PYC activity (i.e., with POX activity) increased the biomass yield coefficient and reduced the maximum specific oxygen consumption rate compared to the wildtype. The presence of PYC in a poxB mutant resulted in a 42% lower maintenance coefficient and a 42% greater biomass yield compared to the wildtype. Providing E. coli with PYC or removing POX increased the threshold specific growth rate at which acetate accumulation began, with an 80% reduction in acetate accumulation observed at a specific growth rate of 0.4 h-1 in the poxB-pyc+ strain. Gene expression analysis suggests utilization of energetically less favorable glucose metabolism via glucokinase and the Entner-Doudoroff pathway in the absence of functional POX, while the upregulation of the phosphotransferase glucose uptake system and several amino acid biosynthetic pathways occurs in the presence of PYC. The physiological and expression changes resulting from these genetic perturbations demonstrate the importance of the pyruvate node in respiration and its impact on acetate overflow during aerobic growth.
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Affiliation(s)
- G N Vemuri
- Center for Molecular BioEngineering, Driftmier Engineering, University of Georgia, Athens, Georgia 30602, USA
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Hoffmann F, Weber J, Rinas U. Metabolic adaptation of Escherichia coli during temperature-induced recombinant protein production: 1. Readjustment of metabolic enzyme synthesis. Biotechnol Bioeng 2002; 80:313-9. [PMID: 12226864 DOI: 10.1002/bit.10379] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The metabolic burden and the stress load resulting from temperature-induced production of human basic fibroblast growth factor is connected to an increase in the respiratory activity of recombinant Escherichia coli, thereby reducing the biomass yield. To study the underlying changes in metabolic enzyme synthesis rates, the radiolabeled proteom was subjected to two-dimen- sional gel electrophoresis. After temperature-induction, the cAMP-CRP controlled dehydrogenases of the pyruvate dehydrogenase complex and the tricarboxylic acid cycle (LpdA and SdhA) were induced four times, reaching a maximum 1 h after the temperature upshift. The more abundant tricarboxylic acid cycle dehydrogenases (Icd and Mdh) were initially produced at reduced rates but regained preshift rates within 30 min. The adenylate energy charge dropped immediately after the temperature upshift but recovered within 1 h. Similar profiles in dehydrogenase synthesis rates and adenylate energy charge were found in a control cultivation of a strain carrying the "empty" parental expression vector. Although both strains exhibited significant differences in growth pattern and respiration rates after the temperature upshift, the adaptation of the energetic state of the cells and the synthesis of enzymes from the energy-generating catabolic pathway did not seem to be affected by the strong overproduction of the recombinant growth factor. In contrast, the synthesis rates of enzymes belonging to the biosynthetic machinery, e.g., translational elongation factors, decreased more strongly in the culture synthesizing the recombinant protein. In control and producing culture, synthesis rates of elongation factors paralleled the respective growth rate profiles. Thus, cells seem to readjust their metabolic activities according to their energetic requirements and, if necessary, at the cost of their biosynthetic capabilities.
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Affiliation(s)
- Frank Hoffmann
- Biochemical Engineering Division, GBF German Research Center for Biotechnology, Mascheroder Weg 1, 38124 Braunschweig, Germany
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du Preez JC, Maré JE, Albertyn J, Kilian SG. Transcriptional repression of ADH2-regulated beta-xylanase production by ethanol in recombinant strains of Saccharomyces cerevisiae. FEMS Yeast Res 2001; 1:233-40. [PMID: 12702349 DOI: 10.1111/j.1567-1364.2001.tb00039.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The regulation of endo-beta-(1,4)-xylanase production by two different strains of Saccharomyces cerevisiae, each transformed with the XYN2 gene from Trichoderma reesei under control of the promoter of the alcohol dehydrogenase II (ADH2) gene of S. cerevisiae, was investigated. In batch culture, the rate of xylanase production was severely reduced by the pulse addition of 390 mmol ethanol l(-1). Pulses of 190-630 mmol ethanol l(-1) into aerobic glucose-limited steady-state continuous cultures reduced the xylanase activity about five-fold and showed that ethanol repressed the ADH2 promoter, as was evident from Northern blot analyses. Derepression of the ADH2-regulated xylanase gene occurred at ethanol concentrations below approximately 50 mmol l(-1).
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Affiliation(s)
- J C du Preez
- Department of Microbiology and Biochemistry, University of the Free State, P.O. Box 339, 9300 Bloemfontein, South Africa.
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Görgens JF, van Zyl WH, Knoetze JH, Hahn-Hägerdal B. The metabolic burden of the PGK1 and ADH2 promoter systems for heterologous xylanase production by Saccharomyces cerevisiae in defined medium. Biotechnol Bioeng 2001; 73:238-45. [PMID: 11257606 DOI: 10.1002/bit.1056] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Five recombinant S. cerevisiae strains were cultivated under identical conditions to quantify the molecular basis of the metabolic burden of heterologous gene expression, and to evaluate mechanisms for the metabolic burden. Two recombinant S. cerevisiae strains, producing Trichoderma reesei xylanase II under control of either the PGK1 or ADH2 promoters, were compared quantitatively with three references strains, where either the heterologous xylanase II (XYN2) gene, or the heterologous gene and the promoter and terminator were omitted from the recombinant plasmid. Neither the replication of multiple copies of the 2-microm-based YEp352 plasmid nor the replication the foreign XYN2 gene represented a metabolic burden to the cell, as the growth of the host organism was not affected. The inclusion of a glycolytic promoter on the recombinant plasmid, however, reduced the maximum specific growth rate (12% to 15%), biomass yield on glucose (8% to 11%), and specific glucose consumption rate (6% to 10%) of the recombinant strains. The presence of the heterologous XYN2 gene on the recombinant plasmid caused a further reduction in the maximum specific growth rate (11% to 14%), biomass yield (4%), and specific glucose consumption rate (12%) of the host strain during active gene expression, which was dictated by the regulatory characteristics of the promoter utilized. The metabolic effect of foreign gene expression was disproportionally large, with respect to on the amount of heterologous protein produced. This was most likely due to an increased energetic demand for the expression of a foreign gene and/or a competition for limiting amounts of transcription or translation factors, biosynthetic precursors or metabolic energy.
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Affiliation(s)
- J F Görgens
- Department of Applied Microbiology, Lund University, Box 124, S-221 00 Lund, Sweden
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El-Mansi M, Anderson KJ, Inche CA, Knowles LK, Platt DJ. Isolation and curing of the Klebsiella pneumoniae large indigenous plasmid using sodium dodecyl sulphate. Res Microbiol 2000; 151:201-8. [PMID: 10865947 DOI: 10.1016/s0923-2508(00)00140-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ability of Klebsiella pneumoniae (NCTC, CL687/80) to produce and, in turn, excrete glutamate has been equated with the presence of a large indigenous plasmid with an apparent molecular mass in the region of 96 +/- 2 kbp (n = 6). Unlike mitomycin C, novobiocine and ethidium bromide (curing agents), the use of sodium dodecyl sulphate (SDS) proved very effective in curing the plasmid with a relatively high frequency (6.25 x 10(-4)). Furthermore, the absence of isocitrate dehydrogenase (ICDH) activity in the cured strain strongly suggests that the structural gene encoding ICDH in this organism, in sharp contrast to all known ICDHs, is plasmid-encoded. Moreover, the SDS-based protocol reported for the isolation of the K. pneumoniae indigenous plasmid has proven successful with other organisms including Pseudomonad and Corynebacteria, as well as in recombinant strains of Escherichia coli.
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Affiliation(s)
- M El-Mansi
- School of Life Sciences, Napier University, Edinburgh, Scotland, UK.
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Wongwicharn A, McNeil B, Harvey LM. Effect of oxygen enrichment on morphology, growth, and heterologous protein production in chemostat cultures of Aspergillus niger B1-D. Biotechnol Bioeng 1999; 65:416-24. [PMID: 10506417 DOI: 10.1002/(sici)1097-0290(19991120)65:4<416::aid-bit6>3.0.co;2-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The response of steady state chemostat cultures of a recombinant Aspergillus niger (B1-D), secreting both a heterologous enzyme (Hen Egg White Lysozyme [HEWL]) and a native enzyme (Glucoamylase), to varying levels of O2 enrichment of the process gas was evaluated. Formation of both the native and the foreign enzyme increased with increasing O2 supply. Conversely, biomass levels and total extracellular protein levels were generally not increased under O2 enriched conditions. Two distinct micromorphologies were apparent in these cultures, one, typically seen under O2 limiting conditions (i. e. at 0 and 10% enrichment levels), tended to be represented by long, sparsely branched hyphal elements, with low percentages of "active" length (i. e. how much of the hypha is cytoplasm filled); whilst, a second micromorphology, typical of O2 enriched cultures at 30 and 50% O2 enrichment, was represented by shorter hyphal elements, with more branching and a higher % "active" length. At these higher O2 levels, formation of a yellow pigment occurred, and signs of culture autolysis were noted. At 50% enrichment, a "stranded" aggregate morphology was apparent, possibly as a response to a hyperoxidant state. Production of both the native enzyme and HEWL correlated well with a simple morphological measure (tip number) or, with % "active" length. It is proposed the morphological changes noted in the cultures were associated with the increased production of both HEWL and glucoamylase.
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Affiliation(s)
- A Wongwicharn
- Strathclyde Fermentation Centre, Department of Bioscience and Biotechnology, Strathclyde University, 204 George Street, Glasgow G1 1XW
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Corchero JL, Villaverde A. Plasmid maintenance inEscherichia coli recombinant cultures is dramatically, steadily, and specifically influenced by features of the encoded proteins. Biotechnol Bioeng 1998. [DOI: 10.1002/(sici)1097-0290(19980620)58:6<625::aid-bit8>3.0.co;2-k] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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50
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Effects of dissolved oxygen and oxygen mass transfer on overexpression of target gene in recombinant E. coli. Enzyme Microb Technol 1997. [DOI: 10.1016/s0141-0229(96)00151-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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