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Mast Y, Ghaderi A, Takors R. Real Case Study of 600 m 3 Bubble Column Fermentations: Spatially Resolved Simulations Unveil Optimization Potentials for l-Phenylalanine Production With Escherichia coli. Biotechnol Bioeng 2024. [PMID: 39450684 DOI: 10.1002/bit.28869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 08/14/2024] [Accepted: 10/10/2024] [Indexed: 10/26/2024]
Abstract
Large-scale fermentations (»100 m³) often encounter concentration gradients which may significantly affect microbial activities and production performance. Reliably investigating such scenarios in silico would allow to optimize bioproduction. But related simulations are very rare in particular for large bubble columns. Here, we pioneer the spatially resolved investigation of a 600 m³ bubble column operating for Escherichia coli based l-phenylalanine fed-batch production. Microbial kinetics are derived from experimental data. Advanced Euler-Lagrange (EL) computational fluid dynamics (CFD) simulations are applied to track individual bubble dynamics that result from a recently developed bubble breakage model. Thereon, the complex nonlinear characteristics of hydrodynamics, mass transfer, and microbial activities are simulated for large scale and compared with real data. As a key characteristic, zones for upriser, downcomer, and circulation cells were identified that dominate mixing and mass transfer. This results in complex gradients of glucose, dissolved oxygen, and microbial rates dividing the bioreactor into sections. Consequently, alternate feed designs are evaluated splitting real feed rates in two feeds at different locations. The opposite reversed installation of feed spots and spargers improved the product synthesis by 6.24% while alternate scenarios increased the growth rate by 11.05%. The results demonstrate how sophisticated, spatially resolved simulations of hydrodynamics, mass transfer, and microbial kinetics help to optimize bioreactors in silico.
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Affiliation(s)
- Yannic Mast
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
| | | | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
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2
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Xu M, Vallières C, Finnis C, Winzer K, Avery SV. Exploiting phenotypic heterogeneity to improve production of glutathione by yeast. Microb Cell Fact 2024; 23:267. [PMID: 39375675 PMCID: PMC11457410 DOI: 10.1186/s12934-024-02536-5] [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: 05/03/2024] [Accepted: 09/25/2024] [Indexed: 10/09/2024] Open
Abstract
BACKGROUND Gene expression noise (variation in gene expression among individual cells of a genetically uniform cell population) can result in heterogenous metabolite production by industrial microorganisms, with cultures containing both low- and high-producing cells. The presence of low-producing individuals may be a factor limiting the potential for high yields. This study tested the hypothesis that low-producing variants in yeast cell populations can be continuously counter-selected, to increase net production of glutathione (GSH) as an exemplar product. RESULTS A counter-selection system was engineered in Saccharomyces cerevisiae based on the known feedback inhibition of gamma-glutamylcysteine synthetase (GSH1) gene expression, which is rate limiting for GSH synthesis: the GSH1 ORF and the counter-selectable marker GAP1 were expressed under control of the TEF1 and GSH-regulated GSH1 promoters, respectively. An 18% increase in the mean cellular GSH level was achieved in cultures of the engineered strain supplemented with D-histidine to counter-select cells with high GAP1 expression (i.e. low GSH-producing cells). The phenotype was non-heritable and did not arise from a generic response to D-histidine, unlike that with certain other test-constructs prepared with alternative markers. CONCLUSIONS The results corroborate that the system developed here improves GSH production by targeting low-producing cells. This supports the potential for exploiting end-product/promoter interactions to enrich high-producing cells in phenotypically heterogeneous populations, in order to improve metabolite production by yeast.
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Affiliation(s)
- Mingzhi Xu
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Cindy Vallières
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Chris Finnis
- Phenotypeca, BioCity Nottingham, Nottingham, NG1 1GF, UK
| | - Klaus Winzer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Simon V Avery
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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3
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Hartmann FSF, Grégoire M, Renzi F, Delvigne F. Single cell technologies for monitoring protein secretion heterogeneity. Trends Biotechnol 2024; 42:1144-1160. [PMID: 38480024 DOI: 10.1016/j.tibtech.2024.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 09/07/2024]
Abstract
Cell-to-cell heterogeneity presents challenges across various fields, from biomedicine to bioproduction, where precise cellular responses are vital. While single cell technologies have significantly enhanced our understanding of population heterogeneity, the predominant focus has been on monitoring intracellular compounds. Recognizing the added complexity introduced by the secretion system, in this review, we first provide a systematic overview of the distinct steps necessary for driving protein secretion. We discuss the various sources of noise acting from the synthesized preprotein to the secretory protein released based on a Gram-positive cellular system as a model. We next explore the applicability of single cell technologies for monitoring protein secretion throughout these functional stages. We also emphasize the importance of applying these single cell technologies for monitoring protein secretion during bioproduction.
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Affiliation(s)
- Fabian Stefan Franz Hartmann
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Mélanie Grégoire
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium; Research Unit in Biology of Microorganisms (URBM), Biology Department, Narilis, University of Namur, Namur, Belgium
| | - Francesco Renzi
- Research Unit in Biology of Microorganisms (URBM), Biology Department, Narilis, University of Namur, Namur, Belgium
| | - Frank Delvigne
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium.
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4
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Kinet R, Richelle A, Colle M, Demaegd D, von Stosch M, Sanders M, Sehrt H, Delvigne F, Goffin P. Giving the cells what they need when they need it: Biosensor-based feeding control. Biotechnol Bioeng 2024; 121:1271-1283. [PMID: 38258490 DOI: 10.1002/bit.28657] [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: 07/28/2023] [Revised: 12/11/2023] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
"Giving the cells exactly what they need, when they need it" is the core idea behind the proposed bioprocess control strategy: operating bioprocess based on the physiological behavior of the microbial population rather than exclusive monitoring of environmental parameters. We are envisioning to achieve this through the use of genetically encoded biosensors combined with online flow cytometry (FCM) to obtain a time-dependent "physiological fingerprint" of the population. We developed a biosensor based on the glnA promoter (glnAp) and applied it for monitoring the nitrogen-related nutritional state of Escherichia coli. The functionality of the biosensor was demonstrated through multiple cultivation runs performed at various scales-from microplate to 20 L bioreactor. We also developed a fully automated bioreactor-FCM interface for on-line monitoring of the microbial population. Finally, we validated the proposed strategy by performing a fed-batch experiment where the biosensor signal is used as the actuator for a nitrogen feeding feedback control. This new generation of process control, -based on the specific needs of the cells, -opens the possibility of improving process development on a short timescale and therewith, the robustness and performance of fermentation processes.
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Affiliation(s)
| | | | | | | | | | | | - Hannah Sehrt
- TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Frank Delvigne
- TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Philippe Goffin
- Molecular and Cellular Biology, University of Brussels, Brussels, Belgium
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Blöbaum L, Torello Pianale L, Olsson L, Grünberger A. Quantifying microbial robustness in dynamic environments using microfluidic single-cell cultivation. Microb Cell Fact 2024; 23:44. [PMID: 38336674 PMCID: PMC10854032 DOI: 10.1186/s12934-024-02318-z] [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: 11/21/2023] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Microorganisms must respond to changes in their environment. Analysing the robustness of functions (i.e. performance stability) to such dynamic perturbations is of great interest in both laboratory and industrial settings. Recently, a quantification method capable of assessing the robustness of various functions, such as specific growth rate or product yield, across different conditions, time frames, and populations has been developed for microorganisms grown in a 96-well plate. In micro-titer-plates, environmental change is slow and undefined. Dynamic microfluidic single-cell cultivation (dMSCC) enables the precise maintenance and manipulation of microenvironments, while tracking single cells over time using live-cell imaging. Here, we combined dMSCC and a robustness quantification method to a pipeline for assessing performance stability to changes occurring within seconds or minutes. RESULTS Saccharomyces cerevisiae CEN.PK113-7D, harbouring a biosensor for intracellular ATP levels, was exposed to glucose feast-starvation cycles, with each condition lasting from 1.5 to 48 min over a 20 h period. A semi-automated image and data analysis pipeline was developed and applied to assess the performance and robustness of various functions at population, subpopulation, and single-cell resolution. We observed a decrease in specific growth rate but an increase in intracellular ATP levels with longer oscillation intervals. Cells subjected to 48 min oscillations exhibited the highest average ATP content, but the lowest stability over time and the highest heterogeneity within the population. CONCLUSION The proposed pipeline enabled the investigation of function stability in dynamic environments, both over time and within populations. The strategy allows for parallelisation and automation, and is easily adaptable to new organisms, biosensors, cultivation conditions, and oscillation frequencies. Insights on the microbial response to changing environments will guide strain development and bioprocess optimisation.
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Affiliation(s)
- Luisa Blöbaum
- Multiscale Bioengineering, Technical Faculty, Bielefeld University, Bielefeld, Germany
- CeBiTec, Bielefeld University, Bielefeld, Germany
| | - Luca Torello Pianale
- Industrial Biotechnology Division, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Lisbeth Olsson
- Industrial Biotechnology Division, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Alexander Grünberger
- Multiscale Bioengineering, Technical Faculty, Bielefeld University, Bielefeld, Germany.
- Microsystems in Bioprocess Engineering, Institute of Process Engineering in Life Sciences, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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Torello Pianale L, Caputo F, Olsson L. Four ways of implementing robustness quantification in strain characterisation. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:195. [PMID: 38115067 PMCID: PMC10729505 DOI: 10.1186/s13068-023-02445-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023]
Abstract
BACKGROUND In industrial bioprocesses, microorganisms are generally selected based on performance, whereas robustness, i.e., the ability of a system to maintain a stable performance, has been overlooked due to the challenges in its quantification and implementation into routine experimental procedures. This work presents four ways of implementing robustness quantification during strain characterisation. One Saccharomyces cerevisiae laboratory strain (CEN.PK113-7D) and two industrial strains (Ethanol Red and PE2) grown in seven different lignocellulosic hydrolysates were assessed for growth-related functions (specific growth rate, product yields, etc.) and eight intracellular parameters (using fluorescent biosensors). RESULTS Using flasks and high-throughput experimental setups, robustness was quantified in relation to: (i) stability of growth functions in response to the seven hydrolysates; (ii) stability of growth functions across different strains to establish the impact of perturbations on yeast metabolism; (iii) stability of intracellular parameters over time; (iv) stability of intracellular parameters within a cell population to indirectly quantify population heterogeneity. Ethanol Red was the best-performing strain under all tested conditions, achieving the highest growth function robustness. PE2 displayed the highest population heterogeneity. Moreover, the intracellular environment varied in response to non-woody or woody lignocellulosic hydrolysates, manifesting increased oxidative stress and unfolded protein response, respectively. CONCLUSIONS Robustness quantification is a powerful tool for strain characterisation as it offers novel information on physiological and biochemical parameters. Owing to the flexibility of the robustness quantification method, its implementation was successfully validated at single-cell as well as high-throughput levels, showcasing its versatility and potential for several applications.
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Affiliation(s)
- Luca Torello Pianale
- Industrial Biotechnology Division, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Fabio Caputo
- Industrial Biotechnology Division, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Lisbeth Olsson
- Industrial Biotechnology Division, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden.
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Guez JS, Lacroix PY, Château T, Vial C. Deep in situ microscopy for real-time analysis of mammalian cell populations in bioreactors. Sci Rep 2023; 13:22045. [PMID: 38086908 PMCID: PMC10716407 DOI: 10.1038/s41598-023-48733-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
An in situ microscope based on pulsed transmitted light illumination via optical fiber was combined to artificial-intelligence to enable for the first time an online cell classification according to well-known cellular morphological features. A 848 192-image database generated during a lab-scale production process of antibodies was processed using a convolutional neural network approach chosen for its accurate real-time object detection capabilities. In order to induce different cell death routes, hybridomas were grown in normal or suboptimal conditions in a stirred tank reactor, in the presence of substrate limitation, medium addition, pH regulation problem or oxygen depletion. Using such an optical system made it possible to monitor real-time the evolution of different classes of animal cells, among which viable, necrotic and apoptotic cells. A class of viable cells displaying bulges in feast or famine conditions was also revealed. Considered as a breakthrough in the catalogue of process analytical tools, in situ microscopy powered by artificial-intelligence is also of great interest for research.
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Affiliation(s)
- Jean-Sébastien Guez
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, 63 000, Clermont-Ferrand, France.
| | - Pierre-Yves Lacroix
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, 63 000, Clermont-Ferrand, France
- Logiroad.AI, 63 178, Aubière, France
| | - Thierry Château
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, 63 000, Clermont-Ferrand, France
- Logiroad.AI, 63 178, Aubière, France
| | - Christophe Vial
- Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, 63 000, Clermont-Ferrand, France
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8
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Lima C, Muhamadali H, Goodacre R. Monitoring Phenotype Heterogeneity at the Single-Cell Level within Bacillus Populations Producing Poly-3-hydroxybutyrate by Label-Free Super-resolution Infrared Imaging. Anal Chem 2023; 95:17733-17740. [PMID: 37997371 DOI: 10.1021/acs.analchem.3c03595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Phenotypic heterogeneity is commonly found among bacterial cells within microbial populations due to intrinsic factors as well as equipping the organisms to respond to external perturbations. The emergence of phenotypic heterogeneity in bacterial populations, particularly in the context of using these bacteria as microbial cell factories, is a major concern for industrial bioprocessing applications. This is due to the potential impact on overall productivity by allowing the growth of subpopulations consisting of inefficient producer cells. Monitoring the spread of phenotypes across bacterial cells within the same population at the single-cell level is key to the development of robust, high-yield bioprocesses. Here, we discuss the novel development of optical photothermal infrared (O-PTIR) spectroscopy to probe phenotypic heterogeneity within Bacillus strains by monitoring the production of the bioplastic poly-3-hydroxybutyrate (PHB) at the single-cell level. Measurements obtained on single-point and in imaging mode show significant variability in the PHB content within bacterial cells, ranging from whether or not a cell produces PHB to variations in the intragranular biochemistry of PHB within bacterial cells. Our results show the ability of O-PTIR spectroscopy to probe PHB production at the single-cell level in a rapid, label-free, and semiquantitative manner. These findings highlight the potential of O-PTIR spectroscopy in single-cell microbial metabolomics as a whole-organism fingerprinting tool that can be used to monitor the dynamic of bacterial populations as well as for understanding their mechanisms for dealing with environmental stress, which is crucial for metabolic engineering research.
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Affiliation(s)
- Cassio Lima
- Centre for Metabolomics Research, Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - Howbeer Muhamadali
- Centre for Metabolomics Research, Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - Royston Goodacre
- Centre for Metabolomics Research, Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K
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9
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Hoang MD, Polte I, Frantzmann L, von den Eichen N, Heins AL, Weuster-Botz D. Impact of mixing insufficiencies on L-phenylalanine production with an Escherichia coli reporter strain in a novel two-compartment bioreactor. Microb Cell Fact 2023; 22:153. [PMID: 37574555 PMCID: PMC10424407 DOI: 10.1186/s12934-023-02165-4] [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: 07/01/2023] [Accepted: 08/01/2023] [Indexed: 08/15/2023] Open
Abstract
BACKGROUND The omnipresence of population heterogeneity in industrial bioprocesses originates from prevailing dynamic bioprocess conditions, which promote differences in the expression of cellular characteristics. Despite the awareness, the concrete consequences of this phenomenon remain poorly understood. RESULTS Therefore, for the first time, a L-phenylalanine overproducing Escherichia coli quadruple reporter strain was established for monitoring of general stress response, growth behavior, oxygen limitation and product formation of single cells based on mTagBFP2, mEmerald, CyOFP1, and mCardinal2 expression measured by flow cytometry. This strain was applied for the fed-batch production of L-phenylalanine from glycerol and ammonia in a stirred-tank bioreactor at homogeneous conditions compared to the same process in a novel two-compartment bioreactor. This two-compartment bioreactor consists of a stirred-tank bioreactor with an initial volume of 0.9 L (homogeneous zone) with a coiled flow inverter with a fixed working volume of 0.45 L as a bypass (limitation zone) operated at a mean hydraulic residence time of 102 s. The product formation was similar in both bioreactor setups with maximum L-phenylalanine concentrations of 21.1 ± 0.6 g L-1 demonstrating the consistency of this study's microbial L-phenylalanine production. However, cell growth was vulnerable to repetitive exposure to the dynamically changing conditions in the two-compartment bioreactor with maximum biomass yields reduced by 21%. The functionality of reporter molecules was approved in the stirred-tank bioreactor cultivation, in which expressed fluorescence levels of all four markers were in accordance with respective process state variables. Additional evaluation of the distributions on single-cell level revealed the presence of population heterogeneity in both bioprocesses. Especially for the marker of the general stress response and the product formation, the corresponding histograms were characterized by bimodal shapes and broad distributions. These phenomena were pronounced particularly at the beginning and the end of the fed-batch process. CONCLUSIONS The here shown findings confirm multiple reporter strains to be a noninvasive tool for monitoring cellular characteristics and identifying potential subpopulations in bioprocesses. In combination with experiments in scale-down setups, these can be utilized for a better physiological understanding of bioprocesses and support future scale-up procedures.
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Affiliation(s)
- Manh Dat Hoang
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
| | - Ingmar Polte
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
| | - Lukas Frantzmann
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
| | - Nikolas von den Eichen
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
| | - Anna-Lena Heins
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany.
| | - Dirk Weuster-Botz
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
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10
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Becker L, Sturm J, Eiden F, Holtmann D. Analyzing and understanding the robustness of bioprocesses. Trends Biotechnol 2023; 41:1013-1026. [PMID: 36959084 DOI: 10.1016/j.tibtech.2023.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/25/2023]
Abstract
The robustness of bioprocesses is becoming increasingly important. The main driving forces of this development are, in particular, increasing demands on product purities as well as economic aspects. In general, bioprocesses exhibit extremely high complexity and variability. Biological systems often have a much higher intrinsic variability compared with chemical processes, which makes the development and characterization of robust processes tedious task. To predict and control robustness, a clear understanding of interactions between input and output variables is necessary. Robust bioprocesses can be realized, for example, by using advanced control strategies for the different unit operations. In this review, we discuss the different biological, technical, and mathematical tools for the analysis and control of bioprocess robustness.
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Affiliation(s)
- Lucas Becker
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany
| | - Jonathan Sturm
- Bioprozesstechnik Group, Westfälische Hochschule, August-Schmidt-Ring 10, 45665 Recklinghausen, Germany; iAMB - Institute of Applied Microbiology, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Frank Eiden
- Bioprozesstechnik Group, Westfälische Hochschule, August-Schmidt-Ring 10, 45665 Recklinghausen, Germany
| | - Dirk Holtmann
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany.
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11
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Hoang MD, Riessner S, Oropeza Vargas JE, von den Eichen N, Heins AL. Influence of Varying Pre-Culture Conditions on the Level of Population Heterogeneity in Batch Cultures with an Escherichia coli Triple Reporter Strain. Microorganisms 2023; 11:1763. [PMID: 37512936 PMCID: PMC10384452 DOI: 10.3390/microorganisms11071763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
When targeting robust, high-yielding bioprocesses, phenomena such as population heterogeneity have to be considered. Therefore, the influence of the conditions which the cells experience prior to the main culture should also be evaluated. Here, the influence of a pre-culture medium (complex vs. minimal medium), optical density for inoculation of the main culture (0.005, 0.02 and 0.0125) and harvest time points of the pre-culture in exponential growth phase (early, mid and late) on the level of population heterogeneity in batch cultures of the Escherichia coli triple reporter strain G7BL21(DE3) in stirred-tank bioreactors was studied. This strain allows monitoring the growth (rrnB-EmGFP), general stress response (rpoS-mStrawberry) and oxygen limitation (nar-TagRFP657) of single cells through the expression of fluorescent proteins. Data from batch cultivations with varying pre-culture conditions were analysed with principal component analysis. According to fluorescence data, the pre-culture medium had the largest impact on population heterogeneities during the bioprocess. While a minimal medium as a pre-culture medium elevated the differences in cellular growth behaviour in the subsequent batch process, a complex medium increased the general stress response and led to a higher population heterogeneity. The latter was promoted by an early harvest of the cells with low inoculation density. Seemingly, nar-operon expression acted independently of the pre-culture conditions.
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Affiliation(s)
- Manh Dat Hoang
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Sophi Riessner
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Jose Enrique Oropeza Vargas
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Nikolas von den Eichen
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
| | - Anna-Lena Heins
- Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, 85748 Garching, Germany
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12
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PHB production from food waste hydrolysates by Halomonas bluephagenesis Harboring PHB operon linked with an essential gene. Metab Eng 2023; 77:12-20. [PMID: 36889504 DOI: 10.1016/j.ymben.2023.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Food wastes can be hydrolyzed into soluble microbial substrates, contributing to sustainability. Halomonas spp.-based Next Generation Industrial Biotechnology (NGIB) allows open, unsterile fermentation, eliminating the need for sterilization to avoid the Maillard reaction that negatively affects cell growth. This is especially important for food waste hydrolysates, which have a high nutrient content but are unstable due to batch, sources, or storage conditions. These make them unsuitable for polyhydroxyalkanoate (PHA) production, which usually requires limitation on either nitrogen, phosphorous, or sulfur. In this study, H. bluephagenesis was constructed by overexpressing the PHA synthesis operon phaCABCn (cloned from Cupriavidus necator) controlled by the essential gene ompW (encoding outer membrane protein W) promoter and the constitutive porin promoter that are continuously expressed at high levels throughout the cell growth process, allowing poly(3-hydroxybutyrate) (PHB) production to proceed in nutrient-rich (also nitrogen-rich) food waste hydrolysates of various sources. The recombinant H. bluephagenesis termed WZY278 generated 22 g L-1 cell dry weight (CDW) containing 80 wt% PHB when cultured in food waste hydrolysates in shake flasks, and it was grown to 70 g L-1 CDW containing 80 wt% PHB in a 7-L bioreactor via fed-batch cultivation. Thus, unsterilizable food waste hydrolysates can become nutrient-rich substrates for PHB production by H. bluephagenesis able to be grown contamination-free under open conditions.
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13
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Boy C, Lesage J, Alfenore S, Gorret N, Guillouet SE. Comparison of plasmid stabilization systems during heterologous isopropanol production in fed-batch bioreactor. J Biotechnol 2023; 366:25-34. [PMID: 36870479 DOI: 10.1016/j.jbiotec.2023.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/20/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023]
Abstract
Strain robustness during production of recombinant molecules is of major interest to ensure bioprocess profitability. The heterogeneity of populations has been shown in the literature as a source of instability in bioprocesses. Thus, the heterogeneity of the population was studied by evaluating the robustness of the strains (stability of plasmid expression, cultivability, membrane integrity and macroscopic cell behavior) during well-controlled fedbatch cultures. On the context of microbial production of chemical molecules, isopropanol (IPA) has been produced by recombinant strains of Cupriavidus necator. Plasmid stability was monitored by the plate count method to assess the impact of isopropanol production on plasmid stability, depending on implanted plasmid stabilization systems for strain engineering designs. With the reference strain Re2133/pEG7c, an isopropanol titer of 15.1 g·L-1 could be achieved. When the isopropanol concentration has reached about 8 g. L-1, cell permeability increased (up to 25 %) and plasmid stability decreased significantly (up to 1.5 decimal reduction rate) resulting in decreased isopropanol production rates. Bioprocess robustness under isopropanol producing conditions was then investigated with two plasmid construction strategies (1) Post Segregational Killing hok/sok (in Re2133/pEG20) and (2) expression of GroESL chaperon proteins (in Re2133/pEG23). Plasmid stability for strain Re2133/pEG20 (PSK hok/sok) appears to be improved up to 11 g. L-1 of IPA compared to the reference strain (8 g. L-1 IPA). Nevertheless, cell permeability followed the same dynamic as the reference strain with a drastic increase around 8 g. L-1 IPA. On the contrary, the Re2133/pEG23 strain made it possible to minimize the cell permeability (with a constant value at 5 % IP permeability) and to increase the growth capacities in response to increased isopropanol concentrations but plasmid stability was the weakest. The metabolic burden, linked to either the overexpression of GroESL chaperones or the PSK hok/sok system, seems to be deleterious for the overall isopropanol production compared to the reference strain (RE2133/pEG7c) even if we have shown that the overexpression chaperones GroESL improve membrane integrity and PSK system hok/sok improve plasmid stability as long as isopropanol concentration does not exceed 11 g L- 1.
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Affiliation(s)
- Catherine Boy
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Julie Lesage
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | | | - Nathalie Gorret
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
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14
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Hanspal N, DeVincentis B, Thomas JA. Modeling multiphase fluid flow, mass transfer, and chemical reactions in bioreactors using large-eddy simulation. Eng Life Sci 2023; 23:e2200020. [PMID: 36751475 PMCID: PMC9893763 DOI: 10.1002/elsc.202200020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 09/20/2022] [Accepted: 10/22/2022] [Indexed: 11/13/2022] Open
Abstract
We present a transient large eddy simulation (LES) modeling approach for simulating the interlinked physics describing free surface hydrodynamics, multiphase mixing, reaction kinetics, and mass transport in bioreactor systems. Presented case-studies include non-reacting and reacting bioreactor systems, modeled through the inclusion of uniform reaction rates and more complex biochemical reactions described using Contois type kinetics. It is shown that the presence of reactions can result in a non-uniform spatially varying species concentration field, the magnitude and extent of which is directly related to the reaction rates and the underlying variations in the local volumetric mass transfer coefficient.
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15
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Dynamic Interplay between O2 Availability, Growth Rates, and the Transcriptome of Yarrowia lipolytica. FERMENTATION-BASEL 2023. [DOI: 10.3390/fermentation9010074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Industrial-sized fermenters differ from the laboratory environment in which bioprocess development initially took place. One of the issues that can lead to reduced productivity on a large scale or even early termination of the process is the presence of bioreactor heterogeneities. This work proposes and adopts a design–build–test–learn-type workflow that estimates the substrate, oxygen, and resulting growth heterogeneities through a compartmental modelling approach and maps Yarrowia lipolytica-specific behavior in this relevant range of conditions. The results indicate that at a growth rate of 0.1 h−1, the largest simulated volume (90 m3) reached partial oxygen limitation. Throughout the fed-batch, the cells experienced dissolved oxygen values from 0 to 75% and grew at rates of 0 to 0.2 h−1. These simulated large-scale conditions were tested in small-scale cultivations, which elucidated a transcriptome with a strong downregulation of various transporter and central carbon metabolism genes during oxygen limitation. The relation between oxygen availability and differential gene expression was dynamic and did not show a simple on–off behavior. This indicates that Y. lipolytica can differentiate between different available oxygen concentrations and adjust its transcription accordingly. The workflow presented can be used for Y. lipolytica-based strain engineering, thereby accelerating bioprocess development.
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16
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Hoang MD, Doan DT, Schmidt M, Kranz H, Kremling A, Heins A. Application of an Escherichia coli triple reporter strain for at-line monitoring of single-cell physiology during L-phenylalanine production. Eng Life Sci 2023; 23:e2100162. [PMID: 36619877 PMCID: PMC9815085 DOI: 10.1002/elsc.202100162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/24/2022] [Accepted: 02/07/2022] [Indexed: 01/11/2023] Open
Abstract
Biotechnological production processes are sustainable approaches for the production of biobased components such as amino acids for food and feed industry. Scale-up from ideal lab-scale bioreactors to large-scale processes is often accompanied by loss in productivity. This may be related to population heterogeneities of cells originating from isogenic cultures that arise due to dynamic non-ideal conditions in the bioreactor. To better understand this phenomenon, deeper insights into single-cell physiologies in bioprocesses are mandatory before scale-up. Here, a triple reporter strain (3RP) was developed by chromosomally integrating the fluorescent proteins mEmerald, CyOFP1, and mTagBFP2 into the L-phenylalanine producing Escherichia coli strain FUS4 (pF81kan) to allow monitoring of growth, oxygen availability, and general stress response of the single cells. Functionality of the 3RP was confirmed in well-mixed lab-scale fed-batch processes with glycerol as carbon source in comparison to the strain without fluorescent proteins, leading to no difference in process performance. Fluorescence levels could successfully reflect the course of related process state variables, revealed population heterogeneities during the transition between different process phases and potentially subpopulations that exhibit superior process performance. Furthermore, indications were found for noise in gene expression as regulation strategy against environmental perturbation.
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Affiliation(s)
- Manh Dat Hoang
- Chair of Biochemical EngineeringDepartment of Energy and Process EngineeringTUM School of Engineering and DesignTechnical University of MunichGarchingGermany
| | - Dieu Thi Doan
- Systems BiotechnologyDepartment of Energy and Process EngineeringTUM School of Engineering and DesignTechnical University of MunichGarchingGermany
| | - Marlen Schmidt
- Gen‐H Genetic Engineering Heidelberg GmbHHeidelbergGermany
| | - Harald Kranz
- Gen‐H Genetic Engineering Heidelberg GmbHHeidelbergGermany
| | - Andreas Kremling
- Systems BiotechnologyDepartment of Energy and Process EngineeringTUM School of Engineering and DesignTechnical University of MunichGarchingGermany
| | - Anna‐Lena Heins
- Chair of Biochemical EngineeringDepartment of Energy and Process EngineeringTUM School of Engineering and DesignTechnical University of MunichGarchingGermany
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17
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Bromig L, von den Eichen N, Weuster-Botz D. Control of parallelized bioreactors I: dynamic scheduling software for efficient bioprocess management in high-throughput systems. Bioprocess Biosyst Eng 2022; 45:1927-1937. [PMID: 36255464 DOI: 10.1007/s00449-022-02798-6] [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: 06/20/2022] [Accepted: 10/03/2022] [Indexed: 12/28/2022]
Abstract
The shift towards high-throughput technologies and automation in research and development in industrial biotechnology is highlighting the need for increased automation competence and specialized software solutions. Within bioprocess development, the trends towards miniaturization and parallelization of bioreactor systems rely on full automation and digital process control. Thus, mL-scale, parallel bioreactor systems require integration into liquid handling stations to perform a range of tasks stretching from substrate addition to automated sampling and sample analysis. To orchestrate these tasks, the authors propose a scheduling software to fully leverage the advantages of a state-of-the-art liquid handling station (LHS) and to enable improved process control and resource allocation. Fixed sequential order execution, the norm in LHS software, results in imperfect timing of essential operations like feeding or Ph control and execution intervals thereof, that are unknown a priori. However, the duration and control of, e.g., the feeding task and their frequency are of great importance for bioprocess control and the design of experiments. Hence, a software solution is presented that allows the orchestration of the respective operations through dynamic scheduling by external LHS control. With the proposed scheduling software, it is possible to define a dynamic process control strategy based on data-driven real-time prioritization and transparent, user-defined constraints. Drivers for a commercial 48 parallel bioreactor system and the related sensor equipment were developed using the SiLA 2 standard greatly simplifying the integration effort. Furthermore, this paper describes the experimental hardware and software setup required for the application use case presented in the second part.
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Affiliation(s)
- Lukas Bromig
- Chair of Biochemical Engineering, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany
| | - Nikolas von den Eichen
- Chair of Biochemical Engineering, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany
| | - Dirk Weuster-Botz
- Chair of Biochemical Engineering, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany.
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18
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Du YH, Wang MY, Yang LH, Tong LL, Guo DS, Ji XJ. Optimization and Scale-Up of Fermentation Processes Driven by Models. Bioengineering (Basel) 2022; 9:bioengineering9090473. [PMID: 36135019 PMCID: PMC9495923 DOI: 10.3390/bioengineering9090473] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/05/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
In the era of sustainable development, the use of cell factories to produce various compounds by fermentation has attracted extensive attention; however, industrial fermentation requires not only efficient production strains, but also suitable extracellular conditions and medium components, as well as scaling-up. In this regard, the use of biological models has received much attention, and this review will provide guidance for the rapid selection of biological models. This paper first introduces two mechanistic modeling methods, kinetic modeling and constraint-based modeling (CBM), and generalizes their applications in practice. Next, we review data-driven modeling based on machine learning (ML), and highlight the application scope of different learning algorithms. The combined use of ML and CBM for constructing hybrid models is further discussed. At the end, we also discuss the recent strategies for predicting bioreactor scale-up and culture behavior through a combination of biological models and computational fluid dynamics (CFD) models.
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Affiliation(s)
- Yuan-Hang Du
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Min-Yu Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Lin-Hui Yang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Ling-Ling Tong
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Dong-Sheng Guo
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
- Correspondence: (D.-S.G.); (X.-J.J.)
| | - Xiao-Jun Ji
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
- Correspondence: (D.-S.G.); (X.-J.J.)
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19
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Co-expression of an isopropanol synthetic operon and eGFP to monitor the robustness of Cupriavidus necator during isopropanol production. Enzyme Microb Technol 2022; 161:110114. [DOI: 10.1016/j.enzmictec.2022.110114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/19/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022]
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20
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Romain B, Delvigne F, Rémond C, Rakotoarivonina H. Control of phenotypic diversification based on serial cultivations on different carbon sources leads to improved bacterial xylanase production. Bioprocess Biosyst Eng 2022; 45:1359-1370. [PMID: 35881245 DOI: 10.1007/s00449-022-02751-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/21/2022] [Indexed: 11/24/2022]
Abstract
Thermobacillus xylanilyticus is a thermophilic and hemicellulolytic bacterium of interest for the production of thermostable hemicellulases. Enzymes' production by this bacterium is challenging, because the proliferation of a cheating subpopulation of cells during exponential growth impairs the production of xylanase after serial cultivations. Accordingly, a strategy of successive cultivations with cells transfers in stationary phase and the use of wheat bran and wheat straw as carbon sources were tested. The ratio between subpopulations and their corresponding metabolic activities were studied by flow cytometry and the resulting hemicellulases production (xylanase, acetyl esterase and β-xylosidase) followed. During serial cultivations, the results pointed out an increase of the enzymatic activities. On xylan, compared to the first cultivation, the xylanase activity increases by 7.15-fold after only four cultivations. On the other hand, the debranching activities were increased by 5.88-fold and 57.2-fold on wheat straw and by 2.77-fold and 3.34-fold on wheat bran for β-xylosidase and acetyl esterase, respectively. The different enzymatic activities then stabilized, reached a plateau and further decreased. Study of the stability and reversibility of the enzyme production revealed cell-to-cell heterogeneities in metabolic activities which could be linked to the reversibility of enzymatic activity changes. Thus, the strategy of successive transfers during the stationary phase of growth, combined with the use of complex lignocellulosic substrates as carbon sources, is an efficient strategy to optimize the hemicellulases production by T. xylanilyticus, by preventing the selection of cheaters.
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Affiliation(s)
- Bouchat Romain
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, AFERE, Reims, France.,Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Frank Delvigne
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Caroline Rémond
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, AFERE, Reims, France
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21
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Hartmann FSF, Udugama IA, Seibold GM, Sugiyama H, Gernaey KV. Digital models in biotechnology: Towards multi-scale integration and implementation. Biotechnol Adv 2022; 60:108015. [PMID: 35781047 DOI: 10.1016/j.biotechadv.2022.108015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/03/2022] [Accepted: 06/27/2022] [Indexed: 12/28/2022]
Abstract
Industrial biotechnology encompasses a large area of multi-scale and multi-disciplinary research activities. With the recent megatrend of digitalization sweeping across all industries, there is an increased focus in the biotechnology industry on developing, integrating and applying digital models to improve all aspects of industrial biotechnology. Given the rapid development of this field, we systematically classify the state-of-art modelling concepts applied at different scales in industrial biotechnology and critically discuss their current usage, advantages and limitations. Further, we critically analyzed current strategies to couple cell models with computational fluid dynamics to study the performance of industrial microorganisms in large-scale bioprocesses, which is of crucial importance for the bio-based production industries. One of the most challenging aspects in this context is gathering intracellular data under industrially relevant conditions. Towards comprehensive models, we discuss how different scale-down concepts combined with appropriate analytical tools can capture intracellular states of single cells. We finally illustrated how the efforts could be used to develop digitals models suitable for both cell factory design and process optimization at industrial scales in the future.
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Affiliation(s)
- Fabian S F Hartmann
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Isuru A Udugama
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan; Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 228 A, 2800 Kgs. Lyngby, Denmark.
| | - Gerd M Seibold
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Hirokazu Sugiyama
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan
| | - Krist V Gernaey
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 228 A, 2800 Kgs. Lyngby, Denmark.
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22
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Thomas JA, Rahman A, Wutz J, Wang Y, DeVincentis B, McGuire B, Cao L. Modeling free surface gas transfer in agitated lab-scale bioreactors. CHEM ENG COMMUN 2022. [DOI: 10.1080/00986445.2022.2084392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
| | - Anisur Rahman
- Operations Science and Technology - Biologics, AbbVie Bioresearch Center, AbbVie Inc, Worcester, Massachusetts, USA
| | - Johannes Wutz
- M-Star Center Europe, GmbH, Sargstedt, Sachsen-Anhalt, Germany
| | - Ying Wang
- Operations Science and Technology - Biologics, AbbVie Bioresearch Center, AbbVie Inc, Worcester, Massachusetts, USA
| | | | - Brendan McGuire
- Operations Science and Technology - Biologics, AbbVie Bioresearch Center, AbbVie Inc, Worcester, Massachusetts, USA
| | - Lei Cao
- Operations Science and Technology - Biologics, AbbVie Bioresearch Center, AbbVie Inc, Worcester, Massachusetts, USA
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23
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Nikolic N, Sauert M, Albanese TG, Moll I. Quantifying heterologous gene expression during ectopic MazF production in Escherichia coli. BMC Res Notes 2022; 15:173. [PMID: 35562780 PMCID: PMC9102682 DOI: 10.1186/s13104-022-06061-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 04/28/2022] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE MazF is a sequence-specific endoribonuclease-toxin of the MazEF toxin-antitoxin system. MazF cleaves single-stranded ribonucleic acid (RNA) regions at adenine-cytosine-adenine (ACA) sequences in the bacterium Escherichia coli. The MazEF system has been used in various biotechnology and synthetic biology applications. In this study, we infer how ectopic mazF overexpression affects production of heterologous proteins. To this end, we quantified the levels of fluorescent proteins expressed in E. coli from reporters translated from the ACA-containing or ACA-less messenger RNAs (mRNAs). Additionally, we addressed the impact of the 5'-untranslated region of these reporter mRNAs under the same conditions by comparing expression from mRNAs that comprise (canonical mRNA) or lack this region (leaderless mRNA). RESULTS Flow cytometry analysis indicates that during mazF overexpression, fluorescent proteins are translated from the canonical as well as leaderless mRNAs. Our analysis further indicates that longer mazF overexpression generally increases the concentration of fluorescent proteins translated from ACA-less mRNAs, however it also substantially increases bacterial population heterogeneity. Finally, our results suggest that the strength and duration of mazF overexpression should be optimized for each experimental setup, to maximize the heterologous protein production and minimize the amount of phenotypic heterogeneity in bacterial populations, which is unfavorable in biotechnological processes.
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Affiliation(s)
- Nela Nikolic
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria.
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria.
- Living Systems Institute, University of Exeter, Exeter, UK.
| | - Martina Sauert
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria
| | - Tanino G Albanese
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria
| | - Isabella Moll
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, Vienna Biocenter (VBC), University of Vienna, Vienna, Austria.
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24
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Minden S, Aniolek M, Sarkizi Shams Hajian C, Teleki A, Zerrer T, Delvigne F, van Gulik W, Deshmukh A, Noorman H, Takors R. Monitoring Intracellular Metabolite Dynamics in Saccharomyces cerevisiae during Industrially Relevant Famine Stimuli. Metabolites 2022; 12:metabo12030263. [PMID: 35323706 PMCID: PMC8953226 DOI: 10.3390/metabo12030263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/08/2022] [Accepted: 03/16/2022] [Indexed: 11/16/2022] Open
Abstract
Carbon limitation is a common feeding strategy in bioprocesses to enable an efficient microbiological conversion of a substrate to a product. However, industrial settings inherently promote mixing insufficiencies, creating zones of famine conditions. Cells frequently traveling through such regions repeatedly experience substrate shortages and respond individually but often with a deteriorated production performance. A priori knowledge of the expected strain performance would enable targeted strain, process, and bioreactor engineering for minimizing performance loss. Today, computational fluid dynamics (CFD) coupled to data-driven kinetic models are a promising route for the in silico investigation of the impact of the dynamic environment in the large-scale bioreactor on microbial performance. However, profound wet-lab datasets are needed to cover relevant perturbations on realistic time scales. As a pioneering study, we quantified intracellular metabolome dynamics of Saccharomyces cerevisiae following an industrially relevant famine perturbation. Stimulus-response experiments were operated as chemostats with an intermittent feed and high-frequency sampling. Our results reveal that even mild glucose gradients in the range of 100 µmol·L−1 impose significant perturbations in adapted and non-adapted yeast cells, altering energy and redox homeostasis. Apparently, yeast sacrifices catabolic reduction charges for the sake of anabolic persistence under acute carbon starvation conditions. After repeated exposure to famine conditions, adapted cells show 2.7% increased maintenance demands.
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Affiliation(s)
- Steven Minden
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany; (S.M.); (M.A.); (C.S.S.H.); (A.T.); (T.Z.)
| | - Maria Aniolek
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany; (S.M.); (M.A.); (C.S.S.H.); (A.T.); (T.Z.)
| | - Christopher Sarkizi Shams Hajian
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany; (S.M.); (M.A.); (C.S.S.H.); (A.T.); (T.Z.)
| | - Attila Teleki
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany; (S.M.); (M.A.); (C.S.S.H.); (A.T.); (T.Z.)
| | - Tobias Zerrer
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany; (S.M.); (M.A.); (C.S.S.H.); (A.T.); (T.Z.)
| | - Frank Delvigne
- Microbial Processes and Interactions (MiPI), TERRA Research and Teaching Centre, Gembloux Agro Bio Tech, University of Liege, 5030 Gembloux, Belgium;
| | - Walter van Gulik
- Department of Biotechnology, Delft University of Technology, van der Maasweg 6, 2629 HZ Delft, The Netherlands;
| | - Amit Deshmukh
- Royal DSM, 2613 AX Delft, The Netherlands; (A.D.); (H.N.)
| | - Henk Noorman
- Royal DSM, 2613 AX Delft, The Netherlands; (A.D.); (H.N.)
- Department of Biotechnology, Delft University of Technology, 2628 CD Delft, The Netherlands
| | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, 70569 Stuttgart, Germany; (S.M.); (M.A.); (C.S.S.H.); (A.T.); (T.Z.)
- Correspondence:
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25
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Heins A, Hoang MD, Weuster‐Botz D. Advances in automated real-time flow cytometry for monitoring of bioreactor processes. Eng Life Sci 2022; 22:260-278. [PMID: 35382548 PMCID: PMC8961054 DOI: 10.1002/elsc.202100082] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/22/2021] [Accepted: 10/27/2021] [Indexed: 12/18/2022] Open
Abstract
Flow cytometry and its technological possibilities have greatly advanced in the past decade as analysis tool for single cell properties and population distributions of different cell types in bioreactors. Along the way, some solutions for automated real-time flow cytometry (ART-FCM) were developed for monitoring of bioreactor processes without operator interference over extended periods with variable sampling frequency. However, there is still great potential for ART-FCM to evolve and possibly become a standard application in bioprocess monitoring and process control. This review first addresses different components of an ART-FCM, including the sampling device, the sample-processing unit, the unit for sample delivery to the flow cytometer and the settings for measurement of pre-processed samples. Also, available algorithms are presented for automated data analysis of multi-parameter fluorescence datasets derived from ART-FCM experiments. Furthermore, challenges are discussed for integration of fluorescence-activated cell sorting into an ART-FCM setup for isolation and separation of interesting subpopulations that can be further characterized by for instance omics-methods. As the application of ART-FCM is especially of interest for bioreactor process monitoring, including investigation of population heterogeneity and automated process control, a summary of already existing setups for these purposes is given. Additionally, the general future potential of ART-FCM is addressed.
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Affiliation(s)
- Anna‐Lena Heins
- Institute of Biochemical EngineeringTechnical University of MunichGarchingGermany
| | - Manh Dat Hoang
- Institute of Biochemical EngineeringTechnical University of MunichGarchingGermany
| | - Dirk Weuster‐Botz
- Institute of Biochemical EngineeringTechnical University of MunichGarchingGermany
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26
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Robustness: linking strain design to viable bioprocesses. Trends Biotechnol 2022; 40:918-931. [PMID: 35120750 DOI: 10.1016/j.tibtech.2022.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 12/18/2022]
Abstract
Microbial cell factories are becoming increasingly popular for the sustainable production of various chemicals. Metabolic engineering has led to the design of advanced cell factories; however, their long-term yield, titer, and productivity falter when scaled up and subjected to industrial conditions. This limitation arises from a lack of robustness - the ability to maintain a constant phenotype despite the perturbations of such processes. This review describes predictable and stochastic industrial perturbations as well as state-of-the-art technologies to counter process variability. Moreover, we distinguish robustness from tolerance and discuss the potential of single-cell studies for improving system robustness. Finally, we highlight ways of achieving consistent and comparable quantification of robustness that can guide the selection of strains for industrial bioprocesses.
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Torello Pianale L, Rugbjerg P, Olsson L. Real-Time Monitoring of the Yeast Intracellular State During Bioprocesses With a Toolbox of Biosensors. Front Microbiol 2022; 12:802169. [PMID: 35069506 PMCID: PMC8776715 DOI: 10.3389/fmicb.2021.802169] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/16/2021] [Indexed: 12/19/2022] Open
Abstract
Industrial fermentation processes strive for high robustness to ensure optimal and consistent performance. Medium components, fermentation products, and physical perturbations may cause stress and lower performance. Cellular stress elicits a range of responses, whose extracellular manifestations have been extensively studied; whereas intracellular aspects remain poorly known due to lack of tools for real-time monitoring. Genetically encoded biosensors have emerged as promising tools and have been used to improve microbial productivity and tolerance toward industrially relevant stresses. Here, fluorescent biosensors able to sense the yeast intracellular environment (pH, ATP levels, oxidative stress, glycolytic flux, and ribosome production) were implemented into a versatile and easy-to-use toolbox. Marker-free and efficient genome integration at a conserved site on chromosome X of Saccharomyces cerevisiae strains and a commercial Saccharomyces boulardii strain was developed. Moreover, multiple biosensors were used to simultaneously monitor different intracellular parameters in a single cell. Even when combined together, the biosensors did not significantly affect key physiological parameters, such as specific growth rate and product yields. Activation and response of each biosensor and their interconnection were assessed using an advanced micro-cultivation system. Finally, the toolbox was used to screen cell behavior in a synthetic lignocellulosic hydrolysate that mimicked harsh industrial substrates, revealing differences in the oxidative stress response between laboratory (CEN.PK113-7D) and industrial (Ethanol Red) S. cerevisiae strains. In summary, the toolbox will allow both the exploration of yeast diversity and physiological responses in natural and complex industrial conditions, as well as the possibility to monitor production processes.
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Affiliation(s)
- Luca Torello Pianale
- Industrial Biotechnology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Peter Rugbjerg
- Industrial Biotechnology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Enduro Genetics ApS, Copenhagen, Denmark
| | - Lisbeth Olsson
- Industrial Biotechnology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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Boy C, Lesage J, Alfenore S, Guillouet SE, Gorret N. Study of plasmid-based expression level heterogeneity under plasmid-curing like conditions in Cupriavidus necator. J Biotechnol 2022; 345:17-29. [PMID: 34995560 DOI: 10.1016/j.jbiotec.2021.12.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 12/24/2021] [Accepted: 12/30/2021] [Indexed: 01/18/2023]
Abstract
Plasmid expression level heterogeneity in Cupriavidus necator was studied in response to stringent culture conditions, supposed to enhance plasmid instability, through plasmid curing strategies. Two plasmid curing strategies were compared based on their efficiency at generating heterogeneity in batch: rifampicin addition and temperature increase. A temperature increase from 30° to 37 °C was the most efficient plasmid curing strategy. To generate a heterogeneous population in terms of plasmid expression levels, successive batches at supra-optimal culture temperature (i.e. 37 °C) were initially conducted. Three distinct fluorescent subpopulations P0 (not fluorescent), P1 (low fluorescence intensity, median = 1 103) and P2 (high fluorescence intensity, median = 6 103) were obtained. From there, the chemostat culture was implemented to study the long-term stress response under well-controlled environment at defined dilution rates. For dilution rates comprised between 0.05 and 0.10 h-1, the subpopulation P2 (62% vs 90%) was favored compared to P1 cells (54% vs 1%), especially when growth rate increased. Our biosensor was efficient at discriminating subpopulation presenting different expression levels under stringent culture conditions. Plus, we showed that controlling growth kinetics had a stabilizing impact on plasmid expression levels, even under heterogeneous expression conditions.
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Affiliation(s)
- Catherine Boy
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Julie Lesage
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | | | | | - Nathalie Gorret
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France.
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Teworte S, Malcı K, Walls LE, Halim M, Rios-Solis L. Recent advances in fed-batch microscale bioreactor design. Biotechnol Adv 2021; 55:107888. [PMID: 34923075 DOI: 10.1016/j.biotechadv.2021.107888] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/25/2021] [Accepted: 12/11/2021] [Indexed: 12/17/2022]
Abstract
Advanced fed-batch microbioreactors mitigate scale up risks and more closely mimic industrial cultivation practices. Recently, high throughput microscale feeding strategies have been developed which improve the accessibility of microscale fed-batch cultivation irrespective of experimental budget. This review explores such technologies and their role in accelerating bioprocess development. Diffusion- and enzyme-controlled feeding achieve a continuous supply of substrate while being simple and affordable. More complex feed profiles and greater process control require additional hardware. Automated liquid handling robots may be programmed to predefined feed profiles and have the sensitivity to respond to deviations in process parameters. Microfluidic technologies have been shown to facilitate both continuous and precise feeding. Holistic approaches, which integrate automated high-throughput fed-batch cultivation with strategic design of experiments and model-based optimisation, dramatically enhance process understanding whilst minimising experimental burden. The incorporation of real-time data for online optimisation of feed conditions can further refine screening. Although the technologies discussed in this review hold promise for efficient, low-risk bioprocess development, the expense and complexity of automated cultivation platforms limit their widespread application. Future attention should be directed towards the development of open-source software and reducing the exclusivity of hardware.
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Affiliation(s)
- Sarah Teworte
- Institute for Bioengineering, School of Engineering, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom
| | - Koray Malcı
- Institute for Bioengineering, School of Engineering, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom; Centre for Synthetic and Systems Biology, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom
| | - Laura E Walls
- Institute for Bioengineering, School of Engineering, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom; Centre for Synthetic and Systems Biology, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom
| | - Murni Halim
- Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Leonardo Rios-Solis
- Institute for Bioengineering, School of Engineering, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom; Centre for Synthetic and Systems Biology, University of Edinburgh, The King's Buildings, Edinburgh EH9 3DW, Scotland, United Kingdom.
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Biodegradation of waste cooking oil and simultaneous production of rhamnolipid biosurfactant by Pseudomonas aeruginosa P7815 in batch and fed-batch bioreactor. Bioprocess Biosyst Eng 2021; 45:309-319. [PMID: 34767073 DOI: 10.1007/s00449-021-02661-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/23/2021] [Indexed: 10/19/2022]
Abstract
Biosurfactants are non-toxic, surface-active biomolecules capable of reducing surface tension (ST) and emulsifying interface at a comparably lower concentration than commercial surfactants. Yet, poor yield, costlier substrates, and complex cultivation processes limit their commercial applications. This study focuses on producing biosurfactants by Pseudomonas aeruginosa P7815 in batch and fed-batch bioreactor systems using waste cooking oil (WCO) as the sole carbon source. The batch study showed a 92% of WCO biodegradation ability of P. aeruginosa producing 11 g L-1 of biosurfactant. To enhance this biosurfactant production, a fed-batch oil feeding strategy was opted to extend the stationary phase of the bacterium and minimize the effects of substrate deprivation. An enhanced biosurfactant production of 16 g L-1 (i.e. 1.5 times of batch study) was achieved at a feed rate of 5.7 g L-1d-1 with almost 94% of WCO biodegradation activity. The biosurfactant was characterized as rhamnolipid using Fourier transform infrared spectroscopy (FTIR), and its interfacial characterization showed ST reduction to 29 ± 1 mN m-1 and effective emulsification stability at pH value of 4, temperature up to 40 °C and salinity up to 40 g L-1. The biosurfactant exhibited antibacterial activity with minimum inhibitory concentration (MIC) values of 100 µg mL-1 and 150 µg mL-1 for pathogenic E. hirae and E. coli, respectively. These findings suggest that biodegradation of WCO by P. aeruginosa in a fed-batch cultivation strategy is a potential alternative for the economical production of biosurfactants, which can be further explored for biomedical, cosmetics, and oil washing/recovery applications.
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Ji X, Lee YJ, Eyster T, Parrillo A, Galosy S, Ao Z, Patel P, Zhu Y. Characterization of cell cycle and apoptosis in Chinese hamster ovary cell culture using flow cytometry for bioprocess monitoring. Biotechnol Prog 2021; 38:e3211. [PMID: 34549552 DOI: 10.1002/btpr.3211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 09/02/2021] [Accepted: 09/12/2021] [Indexed: 11/09/2022]
Abstract
Chinese hamster ovary (CHO) cells are by far the most important mammalian cell lines used for producing antibodies and other therapeutic proteins. It is critical to fully understand their physiological conditions during a bioprocess in order to achieve the highest productivity and the desired product quality. Flow cytometry technology possesses unique advantages for measuring multiple cellular attributes for a given cell and examining changes in cell culture heterogeneity over time that can be used as metrics for enhanced process understanding and control strategy. Flow cytometry-based assays were utilized to examine the progression of cell cycle and apoptosis in three case studies using different antibody-producing CHO cell lines in both fed-batch and perfusion bioprocesses. In our case studies, we found that G0/G1 phase distribution and early apoptosis accumulation responded to subtle changes in culture conditions, such as pH shifting or momentary glucose depletion. In a perfusion process, flow cytometry provided an insightful understanding of the cell physiological status under a hypothermic condition. More importantly, these changes in cell cycle and apoptosis were not detected by a routine trypan blue exclusion-based cell counting and viability measurement. In summary, integration of flow cytometry into bioprocesses as a process analytical technology tool can be beneficial for establishing optimum process conditions and process control.
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Affiliation(s)
- Xiaodan Ji
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Young Je Lee
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Tom Eyster
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Alexis Parrillo
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Sybille Galosy
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Zhaohui Ao
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Pramthesh Patel
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
| | - Yuan Zhu
- Biopharm Process Development, GlaxoSmithKline, Philadelphia, Pennsylvania, USA
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Chen S, Gong P, Zhang J, Shan Y, Han X, Zhang L. Use of qPCR for the analysis of population heterogeneity and dynamics during Lactobacillus delbrueckii spp. bulgaricus batch fculture. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2021; 49:1-10. [PMID: 33356615 DOI: 10.1080/21691401.2020.1860074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Direct molecular methods such as real-time polymerase chain reaction (qPCR) and propidium monoazide (PMA)-qPCR have been successfully used for quantifying viable microorganisms in the food industry. This study attempted to use qPCR and PMA-qPCR for quantifying Lactobacillus delbrueckii spp. bulgaricus sp1.1 physiological states. The qPCR standards of the 16S rRNA gene were employed to calibrate the qPCR assay, which contributed to an amplification efficiency of 98.42%. The number of copies of the 16S rRNA gene was linearly related to cell density, and this linear relationship was used to construct a quantitative curve (R2 =0.9981) with a detection limit of 15.1 colony-forming units mL-1·reaction-1. qPCR in combination with an optimal PMA concentration (60 μM) helped in discriminating and quantifying the viable cells, without any interference by heat-killed cells. Compared with the conventional methods, the population heterogeneity of viable, culturable, dormant-like and membrane-permeabilized cells were well identified and quantified using qPCR during L. delbrueckii spp. bulgaricus sp1.1 batch culture. Despite the restriction in the enumeration of lysed cells, qPCR-based methods facilitated reliable identification and quantification of bacterial physiological states and provided additional knowledge on the dynamics of L. delbrueckii spp. bulgaricus sp1.1 physiological states.
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Affiliation(s)
- Shiwei Chen
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China
| | - Pimin Gong
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China
| | - Jianming Zhang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China
| | - Yujuan Shan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China
| | - Xue Han
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China
| | - Lanwei Zhang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China.,College of Food Science and Engineering, Ocean University of China, Qingdao, China
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Zoz F, Guyot S, Grandvalet C, Ragon M, Lesniewska E, Dupont S, Firmesse O, Carpentier B, Beney L. Management of Listeria monocytogenes on Surfaces via Relative Air Humidity: Key Role of Cell Envelope. Foods 2021; 10:foods10092002. [PMID: 34574112 PMCID: PMC8468791 DOI: 10.3390/foods10092002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 12/25/2022] Open
Abstract
Although relative air humidity (RH) strongly influences microbial survival, its use for fighting surface pathogens in the food industry has been inadequately considered. We asked whether RH control could destroy Listeria monocytogenes EGDe by envelope damage. The impact of dehydration in phosphate-buffered saline (PBS) at 75%, 68%, 43% and 11% RH on the bacterial envelope was investigated using flow cytometry and atomic force microscopy. Changes after rehydration in the protein secondary structure and peptidoglycan were investigated by infrared spectroscopy. Complementary cultivability measurements were performed by running dehydration–rehydration with combinations of NaCl (3–0.01%), distilled water, city water and PBS. The main results show that cell membrane permeability and cell envelope were greatly altered during dehydration in PBS at 68% RH followed by rapid rehydration. This damage led cells to recover only 67% of their initial volume after rehydration. Moreover, the most efficient way to destroy cells was dehydration and rehydration in city water. Our study indicates that rehydration of dried, sullied foods on surfaces may improve current cleaning procedures in the food industry.
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Affiliation(s)
- Fiona Zoz
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
- Mérieux NutriSciences–70 Mail Marcel Cachin, F-38600 Fontaine, France
| | - Stéphane Guyot
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
- Correspondence: ; Tel.: +33-3-8077-2387
| | - Cosette Grandvalet
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
| | - Mélanie Ragon
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
| | - Eric Lesniewska
- ICB UMR CNRS 6303, Université de Bourgogne Franche-Comté, F-21078 Dijon, France;
| | - Sébastien Dupont
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
| | - Olivier Firmesse
- Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Université Paris-Est, F-94700 Maisons-Alfort, France; (O.F.); (B.C.)
| | - Brigitte Carpentier
- Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Université Paris-Est, F-94700 Maisons-Alfort, France; (O.F.); (B.C.)
| | - Laurent Beney
- Univ. Bourgogne Franche-Comté, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France; (F.Z.); (C.G.); (M.R.); (S.D.); (L.B.)
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Conacher CG, Luyt NA, Naidoo-Blassoples RK, Rossouw D, Setati ME, Bauer FF. The ecology of wine fermentation: a model for the study of complex microbial ecosystems. Appl Microbiol Biotechnol 2021; 105:3027-3043. [PMID: 33834254 DOI: 10.1007/s00253-021-11270-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/30/2021] [Accepted: 04/04/2021] [Indexed: 12/11/2022]
Abstract
The general interest in microbial ecology has skyrocketed over the past decade, driven by technical advances and by the rapidly increasing appreciation of the fundamental services that these ecosystems provide. In biotechnology, ecosystems have many more functionalities than single species, and, if properly understood and harnessed, will be able to deliver better outcomes for almost all imaginable applications. However, the complexity of microbial ecosystems and of the interactions between species has limited their applicability. In research, next generation sequencing allows accurate mapping of the microbiomes that characterise ecosystems of biotechnological and/or medical relevance. But the gap between mapping and understanding, to be filled by "functional microbiomics", requires the collection and integration of many different layers of complex data sets, from molecular multi-omics to spatial imaging technologies to online ecosystem monitoring tools. Holistically, studying the complexity of most microbial ecosystems, consisting of hundreds of species in specific spatial arrangements, is beyond our current technical capabilities, and simpler model systems with fewer species and reduced spatial complexity are required to establish the fundamental rules of ecosystem functioning. One such ecosystem, the ecosystem responsible for natural alcoholic fermentation, can provide an excellent tool to study evolutionarily relevant interactions between multiple species within a relatively easily controlled environment. This review will critically evaluate the approaches that are currently implemented to dissect the cellular and molecular networks that govern this ecosystem. KEY POINTS: • Evolutionarily isolated fermentation ecosystem can be used as an ecological model. • Experimental toolbox is gearing towards mechanistic understanding of this ecosystem. • Integration of multidisciplinary datasets is key to predictive understanding.
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Affiliation(s)
- C G Conacher
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, 7600, South Africa
| | - N A Luyt
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, 7600, South Africa
| | - R K Naidoo-Blassoples
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, 7600, South Africa
| | - D Rossouw
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, 7600, South Africa
| | - M E Setati
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, 7600, South Africa
| | - F F Bauer
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, 7600, South Africa.
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Understanding gradients in industrial bioreactors. Biotechnol Adv 2020; 46:107660. [PMID: 33221379 DOI: 10.1016/j.biotechadv.2020.107660] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/22/2020] [Accepted: 11/14/2020] [Indexed: 01/07/2023]
Abstract
Gradients in industrial bioreactors have attracted substantial research attention since exposure to fluctuating environmental conditions has been shown to lead to changes in the metabolome, transcriptome as well as population heterogeneity in industrially relevant microorganisms. Such changes have also been found to impact key process parameters like the yield on substrate and the productivity. Hence, understanding gradients is important from both the academic and industrial perspectives. In this review the causes of gradients are outlined, along with their impact on microbial physiology. Quantifying the impact of gradients requires a detailed understanding of both fluid flow inside industrial equipment and microbial physiology. This review critically examines approaches used to investigate gradients including large-scale experimental work, computational methods and scale-down approaches. Avenues for future work have been highlighted, particularly the need for further coordinated development of both in silico and experimental tools which can be used to further the current understanding of gradients in industrial equipment.
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Wang G, Haringa C, Noorman H, Chu J, Zhuang Y. Developing a Computational Framework To Advance Bioprocess Scale-Up. Trends Biotechnol 2020; 38:846-856. [DOI: 10.1016/j.tibtech.2020.01.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 01/10/2023]
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Wright NR, Wulff T, Palmqvist EA, Jørgensen TR, Workman CT, Sonnenschein N, Rønnest NP, Herrgård MJ. Fluctuations in glucose availability prevent global proteome changes and physiological transition during prolonged chemostat cultivations of
Saccharomyces cerevisiae. Biotechnol Bioeng 2020; 117:2074-2088. [DOI: 10.1002/bit.27353] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/09/2020] [Indexed: 11/06/2022]
Affiliation(s)
- Naia R. Wright
- Novo Nordisk A/S Bagsværd Denmark
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark Lyngby Denmark
- Department of Biotechnology and BiomedicineTechnical University of Denmark Lyngby Denmark
| | - Tune Wulff
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark Lyngby Denmark
| | | | - Thomas R. Jørgensen
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark Lyngby Denmark
| | - Christopher T. Workman
- Department of Biotechnology and BiomedicineTechnical University of Denmark Lyngby Denmark
| | - Nikolaus Sonnenschein
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark Lyngby Denmark
- Department of Biotechnology and BiomedicineTechnical University of Denmark Lyngby Denmark
| | | | - Markus J. Herrgård
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark Lyngby Denmark
- BioInnovation Institute København N Denmark
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38
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Environmental drivers of metabolic heterogeneity in clonal microbial populations. Curr Opin Biotechnol 2020; 62:202-211. [DOI: 10.1016/j.copbio.2019.11.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/15/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023]
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Wang B, Wang Z, Chen T, Zhao X. Development of Novel Bioreactor Control Systems Based on Smart Sensors and Actuators. Front Bioeng Biotechnol 2020; 8:7. [PMID: 32117906 PMCID: PMC7011095 DOI: 10.3389/fbioe.2020.00007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 01/07/2020] [Indexed: 01/15/2023] Open
Abstract
Bioreactors of various forms have been widely used in environmental protection, healthcare, industrial biotechnology, and space exploration. Robust demand in the field stimulated the development of novel designs of bioreactor geometries and process control strategies and the evolution of the physical structure of the control system. After the introduction of digital computers to bioreactor process control, a hierarchical structure control system (HSCS) for bioreactors has become the dominant physical structure, having high efficiency and robustness. However, inherent drawbacks of the HSCS for bioreactors have produced a need for a more consolidated solution of the control system. With the fast progress in sensors, machinery, and information technology, the development of a flat organizational control system (FOCS) for bioreactors based on parallel distributed smart sensors and actuators may provide a more concise solution for process control in bioreactors. Here, we review the evolution of the physical structure of bioreactor control systems and discuss the properties of the novel FOCS for bioreactors and related smart sensors and actuators and their application circumstances, with the hope of further improving the efficiency, robustness, and economics of bioprocess control.
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Affiliation(s)
- Baowei Wang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Zhiwen Wang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Tao Chen
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Xueming Zhao
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
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Heins AL, Reyelt J, Schmidt M, Kranz H, Weuster-Botz D. Development and characterization of Escherichia coli triple reporter strains for investigation of population heterogeneity in bioprocesses. Microb Cell Fact 2020; 19:14. [PMID: 31992282 PMCID: PMC6988206 DOI: 10.1186/s12934-020-1283-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 01/12/2020] [Indexed: 12/17/2022] Open
Abstract
Background Today there is an increasing demand for high yielding robust and cost efficient biotechnological production processes. Although cells in these processes originate from isogenic cultures, heterogeneity induced by intrinsic and extrinsic influences is omnipresent. To increase understanding of this mechanistically poorly understood phenomenon, advanced tools that provide insights into single cell physiology are needed. Results Two Escherichia coli triple reporter strains have been designed based on the industrially relevant production host E. coli BL21(DE3) and a modified version thereof, E. coli T7E2. The strains carry three different fluorescence proteins chromosomally integrated. Single cell growth is followed with EmeraldGFP (EmGFP)-expression together with the ribosomal promoter rrnB. General stress response of single cells is monitored by expression of sigma factor rpoS with mStrawberry, whereas expression of the nar-operon together with TagRFP657 gives information about oxygen limitation of single cells. First, the strains were characterized in batch operated stirred-tank bioreactors in comparison to wildtype E. coli BL21(DE3). Afterwards, applicability of the triple reporter strains for investigation of population heterogeneity in bioprocesses was demonstrated in continuous processes in stirred-tank bioreactors at different growth rates and in response to glucose and oxygen perturbation simulating gradients on industrial scale. Population and single cell level physiology was monitored evaluating general physiology and flow cytometry analysis of fluorescence distributions of the triple reporter strains. Although both triple reporter strains reflected physiological changes that were expected based on the expression characteristics of the marker proteins, the triple reporter strain based on E. coli T7E2 showed higher sensitivity in response to environmental changes. For both strains, noise in gene expression was observed during transition from phases of non-growth to growth. Apparently, under some process conditions, e.g. the stationary phase in batch cultures, the fluorescence response of EmGFP and mStrawberry is preserved, whereas TagRFP657 showed a distinct response. Conclusions Single cell growth, general stress response and oxygen limitation of single cells could be followed using the two triple reporter strains developed in this study. They represent valuable tools to study population heterogeneity in bioprocesses significantly increasing the level of information compared to the use of single reporter strains.
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Affiliation(s)
- Anna-Lena Heins
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany.
| | - Jan Reyelt
- Gene Bridges GmbH, Im Neuenheimer Feld 584, 69120, Heidelberg, Germany
| | - Marlen Schmidt
- Gene Bridges GmbH, Im Neuenheimer Feld 584, 69120, Heidelberg, Germany
| | - Harald Kranz
- Gene Bridges GmbH, Im Neuenheimer Feld 584, 69120, Heidelberg, Germany
| | - Dirk Weuster-Botz
- Technical University of Munich, Institute of Biochemical Engineering, Boltzmannstr. 15, 85748, Garching, Germany
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Wang G, Haringa C, Tang W, Noorman H, Chu J, Zhuang Y, Zhang S. Coupled metabolic-hydrodynamic modeling enabling rational scale-up of industrial bioprocesses. Biotechnol Bioeng 2019; 117:844-867. [PMID: 31814101 DOI: 10.1002/bit.27243] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/28/2019] [Accepted: 11/30/2019] [Indexed: 12/13/2022]
Abstract
Metabolomics aims to address what and how regulatory mechanisms are coordinated to achieve flux optimality, different metabolic objectives as well as appropriate adaptations to dynamic nutrient availability. Recent decades have witnessed that the integration of metabolomics and fluxomics within the goal of synthetic biology has arrived at generating the desired bioproducts with improved bioconversion efficiency. Absolute metabolite quantification by isotope dilution mass spectrometry represents a functional readout of cellular biochemistry and contributes to the establishment of metabolic (structured) models required in systems metabolic engineering. In industrial practices, population heterogeneity arising from fluctuating nutrient availability frequently leads to performance losses, that is reduced commercial metrics (titer, rate, and yield). Hence, the development of more stable producers and more predictable bioprocesses can benefit from a quantitative understanding of spatial and temporal cell-to-cell heterogeneity within industrial bioprocesses. Quantitative metabolomics analysis and metabolic modeling applied in computational fluid dynamics (CFD)-assisted scale-down simulators that mimic industrial heterogeneity such as fluctuations in nutrients, dissolved gases, and other stresses can procure informative clues for coping with issues during bioprocessing scale-up. In previous studies, only limited insights into the hydrodynamic conditions inside the industrial-scale bioreactor have been obtained, which makes case-by-case scale-up far from straightforward. Tracking the flow paths of cells circulating in large-scale bioreactors is a highly valuable tool for evaluating cellular performance in production tanks. The "lifelines" or "trajectories" of cells in industrial-scale bioreactors can be captured using Euler-Lagrange CFD simulation. This novel methodology can be further coupled with metabolic (structured) models to provide not only a statistical analysis of cell lifelines triggered by the environmental fluctuations but also a global assessment of the metabolic response to heterogeneity inside an industrial bioreactor. For the future, the industrial design should be dependent on the computational framework, and this integration work will allow bioprocess scale-up to the industrial scale with an end in mind.
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Affiliation(s)
- Guan Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Cees Haringa
- Transport Phenomena, Chemical Engineering Department, Delft University of Technology, Delft, The Netherlands.,DSM Biotechnology Center, Delft, The Netherlands
| | - Wenjun Tang
- DSM Biotechnology Center, Delft, The Netherlands
| | - Henk Noorman
- DSM Biotechnology Center, Delft, The Netherlands.,Bioprocess Engineering, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Ju Chu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Siliang Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
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42
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Lara AR, Jaén KE, Folarin O, Keshavarz-Moore E, Büchs J. Effect of the oxygen transfer rate on oxygen-limited production of plasmid DNA by Escherichia coli. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.107303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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43
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Heins AL, Johanson T, Han S, Lundin L, Carlquist M, Gernaey KV, Sørensen SJ, Eliasson Lantz A. Quantitative Flow Cytometry to Understand Population Heterogeneity in Response to Changes in Substrate Availability in Escherichia coli and Saccharomyces cerevisiae Chemostats. Front Bioeng Biotechnol 2019; 7:187. [PMID: 31448270 PMCID: PMC6691397 DOI: 10.3389/fbioe.2019.00187] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/18/2019] [Indexed: 12/20/2022] Open
Abstract
Microbial cells in bioprocesses are usually described with averaged parameters. But in fact, single cells within populations vary greatly in characteristics such as stress resistance, especially in response to carbon source gradients. Our aim was to introduce tools to quantify population heterogeneity in bioprocesses using a combination of reporter strains, flow cytometry, and easily comprehensible parameters. We calculated mean, mode, peak width, and coefficient of variance to describe distribution characteristics and temporal shifts in fluorescence intensity. The skewness and the slope of cumulative distribution function plots illustrated differences in distribution shape. These parameters are person-independent and precise. We demonstrated this by quantifying growth-related population heterogeneity of Saccharomyces cerevisiae and Escherichia coli reporter strains in steady-state of aerobic glucose-limited chemostat cultures at different dilution rates and in response to glucose pulses. Generally, slow-growing cells showed stronger responses to glucose excess than fast-growing cells. Cell robustness, measured as membrane integrity after exposure to freeze-thaw treatment, of fast-growing cells was strongly affected in subpopulations of low membrane robustness. Glucose pulses protected subpopulations of fast-growing but not slower-growing yeast cells against membrane damage. Our parameters could successfully describe population heterogeneity, thereby revealing physiological characteristics that might have been overlooked during traditional averaged analysis.
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Affiliation(s)
- Anna-Lena Heins
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark
| | | | - Shanshan Han
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Luisa Lundin
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Magnus Carlquist
- Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Krist V Gernaey
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Søren J Sørensen
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Anna Eliasson Lantz
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark
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Jaén KE, Velázquez D, Sigala JC, Lara AR. Design of a microaerobically inducible replicon for high-yield plasmid DNA production. Biotechnol Bioeng 2019; 116:2514-2525. [PMID: 31232477 DOI: 10.1002/bit.27091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 01/11/2023]
Abstract
A pUC-derived replicon inducible by oxygen limitation was designed and tested in fed-batch cultures of Escherichia coli. It included the addition of a second inducible copy of rnaII, the positive replication control element. The rnaII gene was expressed from Ptrc and cloned into pUC18 to test the hypothesis that the ratio of the positive control molecule RNAII to the negative control element, RNAI, was the determinant of plasmid copy number per chromosome (PCN). The construct was evaluated in several E. coli strains. Evaluations of the RNAII/RNAI ratio, PCN and plasmid yield normalized to biomass (YpDNA/X ) were performed and the initial hypothesis was probed. Furthermore, in high cell-density cultures in shake flasks, an outstanding amount of 126 mg/L of plasmid was produced. The microaerobically inducible plasmid was obtained by cloning the rnaII gene under the control of the oxygen-responsive Vitreoscilla stercoraria hemoglobin promoter. For this plasmid, but not for pUC18, the RNAII/RNAI ratio, PCN and YpDNA/X efficiently increased after the shift to the microaerobic regime in fed-batch cultures in a 1 L bioreactor. The YpDNA/X of the inducible plasmid reached 12 mg/g at the end of the fed-batch but the original pUC18 only reached ca. 6 mg/g. The proposed plasmid is a valuable alternative for the operation and scale-up of plasmid DNA production processes in which mass transfer limitations will not represent an issue.
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Affiliation(s)
- Karim E Jaén
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Mexico City, Mexico
| | - Daniela Velázquez
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Mexico City, Mexico
| | - Juan-Carlos Sigala
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Mexico City, Mexico
| | - Alvaro R Lara
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Mexico City, Mexico
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45
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Jaén KE, Velazquez D, Delvigne F, Sigala JC, Lara AR. Engineering E. coli for improved microaerobic pDNA production. Bioprocess Biosyst Eng 2019; 42:1457-1466. [PMID: 31079222 DOI: 10.1007/s00449-019-02142-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 03/20/2019] [Accepted: 05/02/2019] [Indexed: 02/08/2023]
Abstract
Escherichia coli strains W3110 and BL21 were engineered for the production of plasmid DNA (pDNA) under aerobic and transitions to microaerobic conditions. The gene coding for recombinase A (recA) was deleted in both strains. In addition, the Vitreoscilla hemoglobin (VHb) gene (vgb) was chromosomally inserted and constitutively expressed in each E. coli recA mutant and wild type. The recA inactivation increased the supercoiled pDNA fraction (SCF) in both strains, while VHb expression improved the pDNA production in W3110, but not in BL21. Therefore, a codon-optimized version of vgb was inserted in strain BL21recA-, which, together with W3110recA-vgb+, was tested in cultures with shifts from aerobic to oxygen-limited regimes. VHb expression lowered the accumulation of fermentative by-products in both strains. VHb-expressing cells displayed higher oxidative activity as indicated by the Redox Sensor Green fluorescence, which was more intense in BL21 than in W3110. Furthermore, VHb expression did not change pDNA production in W3110, but decreased it in BL21. These results are useful for understanding the physiological effects of VHb expression in two industrially relevant E. coli strains, and for the selection of a host for pDNA production.
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Affiliation(s)
- Karim E Jaén
- Posgrado en Ciencias Naturales e Ingeniería, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico
| | - Daniela Velazquez
- Posgrado en Ciencias Naturales e Ingeniería, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico
| | - Frank Delvigne
- Gembloux Agro-Bio Tech, TERRA Research and Teaching Centre, Microbial Processes and Interactions (MiPI), University of Liege, Gembloux, Belgium
| | - Juan-Carlos Sigala
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico
| | - Alvaro R Lara
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Vasco de Quiroga 4871, Santa Fe, 05348, Mexico City, Mexico.
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46
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Heins AL, Lundin L, Nunes I, Gernaey KV, Sørensen SJ, Lantz AE. The effect of acetate on population heterogeneity in different cellular characteristics of Escherichia coli in aerobic batch cultures. Biotechnol Prog 2019; 35:e2796. [PMID: 30816011 DOI: 10.1002/btpr.2796] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/07/2019] [Accepted: 02/22/2019] [Indexed: 01/14/2023]
Abstract
Acetate as the major by-product in industrial-scale bioprocesses with Escherichia coli is found to decrease process efficiency as well as to be toxic to cells, which has several effects like a significant induction of cellular stress responses. However, the underlying phenomena are poorly explored. Therefore, we studied time-resolved population heterogeneity of the E. coli growth reporter strain MG1655/pGS20PrrnBGFPAAV expressing destabilized green fluorescent protein during batch growth on acetate and glucose as sole carbon sources. Additionally, we applied five fluorescent stains targeting different cellular properties (viability as well as metabolic and respiratory activity). Quantitative analysis of flow cytometry data verified that bacterial populations in the bioreactor are more heterogeneous in growth as well as stronger metabolically challenged during growth on acetate as sole carbon source, compared to growth on glucose or acetate after diauxic shift. Interestingly, with acetate as sole carbon source, significant subpopulations were found with some cells that seem to be more robust than the rest of the population. In conclusion, following batch cultures population heterogeneity was evident in all measured parameters. Our approach enabled a deeper study of heterogeneity during growth on the favored substrate glucose as well as on the toxic by-product acetate. Using a combination of activity fluorescent dyes proved to be an accurate and fast alternative as well as a supplement to the use of a reporter strain. However, the choice of combination of stains should be well considered depending on which population traits to aim for.
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Affiliation(s)
- Anna-Lena Heins
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.,Institute of Biochemical Engineering, Technical University of Munich, Garching, Germany
| | - Luisa Lundin
- Department of Biology, Section of Microbiology, University of Copenhagen, Copenhagen, Denmark.,Division of Scientific Support, Becton-Dickison biosciences, Erembodegem, Belgium
| | - Inês Nunes
- Department of Biology, Section of Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Krist V Gernaey
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Søren J Sørensen
- Department of Biology, Section of Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Anna Eliasson Lantz
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
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47
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Pousti M, Joly M, Roberge P, Amirdehi MA, Bégin-Drolet A, Greener J. Linear Scanning ATR-FTIR for Chemical Mapping and High-Throughput Studies of Pseudomonas sp. Biofilms in Microfluidic Channels. Anal Chem 2018; 90:14475-14483. [DOI: 10.1021/acs.analchem.8b04279] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Mohammad Pousti
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Maxime Joly
- Département de génie mécanique, Faculté des sciences et de génie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Patrice Roberge
- Département de génie mécanique, Faculté des sciences et de génie, Université Laval, Québec, QC G1V 0A6, Canada
| | | | - Andre Bégin-Drolet
- Département de génie mécanique, Faculté des sciences et de génie, Université Laval, Québec, QC G1V 0A6, Canada
| | - Jesse Greener
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec, QC G1V 0A6, Canada
- CHU de Quebec Research Centre, Laval University, 10 rue de l’Espinay, Québec, QC G1L 3L5, Canada
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48
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Wang T, Dunlop MJ. Controlling and exploiting cell-to-cell variation in metabolic engineering. Curr Opin Biotechnol 2018; 57:10-16. [PMID: 30261323 DOI: 10.1016/j.copbio.2018.08.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/16/2018] [Accepted: 08/29/2018] [Indexed: 12/30/2022]
Abstract
Individual cells within a population can display diverse phenotypes due to differences in their local environment, genetic variation, and stochastic expression of genes. Understanding this cell-to-cell variation is important for metabolic engineering applications because variability can impact production. For instance, recent studies have shown that production can be highly heterogeneous among engineered cells, and strategies that manage this diversity improve yields of biosynthetic products. These results suggest the potential of controlling variation as a novel approach towards improving performance of engineered cells. In this review, we focus on identifying the origins of cell-to-cell variation in metabolic engineering applications and discuss recent developments on strategies that can be employed to diminish, accept, or even exploit cell-to-cell variation.
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Affiliation(s)
- Tiebin Wang
- Molecular Biology, Cell Biology & Biochemistry Program, Boston University, Boston, MA, USA; Biological Design Center, Boston University, Boston, MA, USA
| | - Mary J Dunlop
- Department of Biomedical Engineering, Boston University, Boston, MA, USA; Biological Design Center, Boston University, Boston, MA, USA.
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