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Neuss A, von Vegesack N, Liepelt R, Büchs J, Barsett Magnus J. Online monitoring of the respiration activity in 96-deep-well microtiter plate Chinese hamster ovary cultures streamlines kill curve experiments. Biotechnol Prog 2024:e3468. [PMID: 38602130 DOI: 10.1002/btpr.3468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/25/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024]
Abstract
Cell line generation of mammalian cells is a time-consuming and labor-intensive process, especially because of challenges in clone selection after transfection. Antibiotics are common selection agents for mammalian cells due to their simplicity of use. However, the optimal antibiotic concentration must be determined with a kill curve experiment before clone selection starts. The traditional kill curve experiments are resource-intensive and time-consuming due to necessary sampling and offline analysis effort. This study, thus, explores the potential of online monitoring the oxygen transfer rate (OTR), as a non-invasive and efficient alternative for kill curve experiments. The OTR is monitored using the Transfer-rate Online Measurement (TOM) system and the micro(μ)-scale Transfer-rate Online Measurement (μTOM) device, which was used for mammalian cells first. It could be shown that the OTR curves for both devices align perfectly, affirming consistent cultivation conditions. The μTOM device proves effective in performing kill curve experiments in 96-deep-well plates without the need for sampling and offline analysis. The streamlined approach reduces medium consumption by 95%, offering a cost-effective and time-efficient solution for kill curve experiments. The study validates the generalizability of the method by applying it to two different CHO cell lines (CHO-K1 and sciCHO) with two antibiotics (puromycin and hygromycin B) each. In conclusion, the broad application of OTR online monitoring for CHO cell cultures in 96-deep-well plates is highlighted. The μTOM device proves as a valuable tool for high-throughput experiments, paving the way for diverse applications, such as media and clone screening, cytotoxicity tests, and scale-up experiments.
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Affiliation(s)
- Anne Neuss
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Nele von Vegesack
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Raoul Liepelt
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Jochen Büchs
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
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Ihling N, Berg C, Paul R, Munkler LP, Mäkinen MEL, Chotteau V, Büchs J. Scale-down of CHO cell cultivation from shake flasks based on oxygen mass transfer allows application of parallelized, non-invasive, and time-resolved monitoring of the oxygen transfer rate in 48-well microtiter plates. Biotechnol J 2023; 18:e2300053. [PMID: 37424196 DOI: 10.1002/biot.202300053] [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: 02/02/2023] [Revised: 06/23/2023] [Accepted: 07/06/2023] [Indexed: 07/11/2023]
Abstract
Cultivating Chinese hamster ovary (CHO) cells in microtiter plates (MTPs) with time-resolved monitoring of the oxygen transfer rate (OTR) is highly desirable to provide process insights at increased throughput. However, monitoring of the OTR in MTPs has not been demonstrated for CHO cells, yet. Hence, a CHO cultivation process was transferred from shake flasks to MTPs to enable monitoring of the OTR in each individual well of a 48-well MTP. For this, the cultivation of an industrially relevant, antibody-producing cell line was transferred from shake flask to MTP based on the volumetric oxygen mass transfer coefficient (kL a). Culture behavior was well comparable (deviation of the final IgG titer less than 10%). Monitoring of the OTR in 48-well MTPs was then used to derive the cytotoxicity of dimethyl sulfoxide (DMSO) based on a dose-response curve in a single experiment using a second CHO cell line. Logistic fitting of the dose-response curve determined after 100 h was used to determine the DMSO concentration that resulted in a cytotoxicity of 50% (IC50). A DMSO concentration of 2.70% ± 0.25% was determined, which agrees with the IC50 previously determined in shake flasks (2.39% ± 0.1%). Non-invasive, parallelized, and time-resolved monitoring of the OTR of CHO cells in MTPs was demonstrated and offers excellent potential to speed up process development and assess cytotoxicity.
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Affiliation(s)
- Nina Ihling
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Christoph Berg
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Richard Paul
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | | | - Meeri E-L Mäkinen
- KTH Royal Institute of Technology, Department of Industrial Biotechnology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Stockholm, Sweden
| | - Veronique Chotteau
- KTH Royal Institute of Technology, Department of Industrial Biotechnology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Stockholm, Sweden
- AdBIOPRO, Competence Centre for Advanced BioProduction by Continuous Processing, KTH, Stockholm, Sweden
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
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Wahjudi SMW, Petrzik T, Oudenne F, Lera Calvo C, Büchs J. Unraveling the potential and constraints associated with corn steep liquor as a nutrient source for industrial fermentations. Biotechnol Prog 2023; 39:e3386. [PMID: 37634939 DOI: 10.1002/btpr.3386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/02/2023] [Accepted: 08/09/2023] [Indexed: 08/29/2023]
Abstract
Costly complex media components such as yeast extract and peptone are still widely used in industrial bioprocesses, despite their ill-defined composition. Side stream products such as corn steep liquor (CSL) present a compelling economical alternative that contains valuable nutrients required for microbial growth, that is, nitrogen and amino acids, but also vitamins, trace elements, and other minerals. However, as a side stream product, CSL may be subject to batch-to-batch variations and compositional heterogeneity. In this study, the Respiration Activity MOnitoring System designed for shake flasks (RAMOS) and 96-well microtiter plates (μTOM) were applied to investigate the potential and constraints of CSL utilization for two model microorganisms: E. coli and B. subtilis. Considering the dry substance content of complex nutrients involved, CSL-based media are more efficient in biomass production than the common lysogeny broth (LB) medium, containing 5 g/L yeast extract, 10 g/L peptone, and 5 g/L NaCl. At a glucose to CSL (glucose/CSL, g/g) ratio of 1/1 (g/g) and 2/1 (g/g), a secondary substrate limitation occurred in E. coli and B. subtilis cultivations, respectively. The study sheds light on differences in the metabolic activity of the two applied model organisms between varying CSL batches, which relate to CSL origin and production process, as well as the effect of targeted nutrient supplementation. Through a targeted nutrient supplementation, the most limiting component of the CSL-glucose medium used for these applied model microorganisms was identified to be ammonium nitrogen. This study proves the suitability of CSL as an alternative nutrient source for E. coli and B. subtilis. The RAMOS and μTOM technique detected differences between CSL batches, allowing easy and early identification of varying batches. A consistent performance of the CSL batches in E. coli and B. subtilis cultivations was demonstrated.
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Affiliation(s)
| | - Thomas Petrzik
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | | | | | - Jochen Büchs
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
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Steinhoff H, Finger M, Osthege M, Golze C, Schito S, Noack S, Büchs J, Grünberger A. Experimental k S estimation: A comparison of methods for Corynebacterium glutamicum from lab to microfluidic scale. Biotechnol Bioeng 2023; 120:1288-1302. [PMID: 36740737 DOI: 10.1002/bit.28345] [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: 08/25/2022] [Revised: 01/16/2023] [Accepted: 02/02/2023] [Indexed: 02/07/2023]
Abstract
Knowledge about the specific affinity of whole cells toward a substrate, commonly referred to as kS , is a crucial parameter for characterizing growth within bioreactors. State-of-the-art methodologies measure either uptake or consumption rates at different initial substrate concentrations. Alternatively, cell dry weight or respiratory data like online oxygen and carbon dioxide transfer rates can be used to estimate kS . In this work, a recently developed substrate-limited microfluidic single-cell cultivation (sl-MSCC) method is applied for the estimation of kS values under defined environmental conditions. This method is benchmarked with two alternative microtiter plate methods, namely high-frequency biomass measurement (HFB) and substrate-limited respiratory activity monitoring (sl-RA). As a model system, the substrate affinity kS of Corynebacterium glutamicum ATCC 13032 regarding glucose was investigated assuming a Monod-type growth response. A kS of <70.7 mg/L (with 95% probability) with HFB, 8.55 ± 1.38 mg/L with sl-RA, and 2.66 ± 0.99 mg/L with sl-MSCC was obtained. Whereas HFB and sl-RA are suitable for a fast initial kS estimation, sl-MSCC allows an affinity estimation by determining tD at concentrations less or equal to the kS value. Thus, sl-MSCC lays the foundation for strain-specific kS estimations under defined environmental conditions with additional insights into cell-to-cell heterogeneity.
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Affiliation(s)
- Heiko Steinhoff
- Multiscale Bioengineering, Bielefeld University, Bielefeld, Germany.,Center for Biotechnology (CeBiTec), Bielefeld, Germany
| | - Maurice Finger
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Michael Osthege
- Institute of Biotechnology, RWTH Aachen University, Aachen, Germany.,Institute of Bio- and Geoscience, IBG-1: Biotechnology, Jülich, Germany
| | - Corinna Golze
- Multiscale Bioengineering, Bielefeld University, Bielefeld, Germany
| | - Simone Schito
- Institute of Bio- and Geoscience, IBG-1: Biotechnology, Jülich, Germany
| | - Stephan Noack
- Institute of Bio- and Geoscience, IBG-1: Biotechnology, Jülich, Germany
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Alexander Grünberger
- Multiscale Bioengineering, Bielefeld University, Bielefeld, Germany.,Center for Biotechnology (CeBiTec), Bielefeld, Germany.,Microsystems in Bioprocess Engineering, Institute of Process Engineering in Life Sciences, Karlsruhe Institute of Technology, Karlsruhe, Germany
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Ihling N, Munkler LP, Paul R, Berg C, Reichenbächer B, Kadisch M, Lang D, Büchs J. Non-invasive and time-resolved measurement of the respiration activity of Chinese hamster ovary cells enables prediction of key culture parameters in shake flasks. Biotechnol J 2022; 17:e2100677. [PMID: 35377965 DOI: 10.1002/biot.202100677] [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: 12/16/2021] [Revised: 03/27/2022] [Accepted: 04/01/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Shake flasks are frequently used for mammalian cell suspension cultures. For process development and routine culture monitoring, information on culture behaviour is needed early on. MAIN METHODS AND MAJOR RESULTS Here, cell-specific oxygen uptake rates (qO2 ) of two CHO cell lines were determined from shake flask experiments by simultaneous measurement of oxygen transfer rates (OTR) and viable cell concentrations (VCC). For cell line one, qO2 decreased from 2.38∙10-10 mmol cell-1 h-1 to 1.02∙10-10 mmol cell-1 h-1 during batch growth. For cell line two, qO2 was constant (1.90∙10-10 mmol h-1 ). Determined qO2 values were used to calculate the VCC from OTR data. Cumulated oxygen consumption and glucose consumption were correlated for both cell lines and enabled calculation of glucose concentrations from OTR data. IgG producing cell line one had an oxygen demand of ∼15 mmoloxygen gglucose -1 , cell line two consumed ∼5 mmoloxygen gglucose -1 . The established correlations for determination of VCC and glucose were successfully transferred to subsequent cultivations for both cell lines. Combined measurement of the OTR and the carbon dioxide transfer rate enabled quantitative determination of the lactate concentration (production and consumption) without sampling. CONCLUSIONS AND IMPLICATIONS Taken together, non-invasive measurement of the respiration activity enabled time-resolved determination of key culture parameters for increased process understanding in shake flasks. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Nina Ihling
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen, D-52074, Germany
| | - Lara Pauline Munkler
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen, D-52074, Germany
| | - Richard Paul
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen, D-52074, Germany
| | - Christoph Berg
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen, D-52074, Germany
| | | | - Marvin Kadisch
- Rentschler Biopharma SE, Erwin-Rentschler-Str. 21, Laupheim, 88471, Germany
| | - Dietmar Lang
- Rentschler Biopharma SE, Erwin-Rentschler-Str. 21, Laupheim, 88471, Germany
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen, D-52074, Germany
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