Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream

The accurate measurement of CO<sub>2</sub> concentration in fermentation off-gas is crucial for monitoring and optimizing bioprocesses, particularly in mammalian cell cultures. In this study, we successfully utilized Raman off-gas spectroscopy to achieve time-resolved prediction of CO<...

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Main Authors: Tobias Wallocha, Michaela Poth
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Fermentation
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Online Access:https://www.mdpi.com/2311-5637/11/6/317
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author Tobias Wallocha
Michaela Poth
author_facet Tobias Wallocha
Michaela Poth
author_sort Tobias Wallocha
collection DOAJ
description The accurate measurement of CO<sub>2</sub> concentration in fermentation off-gas is crucial for monitoring and optimizing bioprocesses, particularly in mammalian cell cultures. In this study, we successfully utilized Raman off-gas spectroscopy to achieve time-resolved prediction of CO<sub>2</sub> concentrations in the fermentation off-gas. Our experiments were conducted using two different media: a commercial medium (medium 1) and an in-house Roche medium (medium 2), each tested with two different lots. The results demonstrated that Raman spectroscopy provides precise and real-time CO<sub>2</sub> measurements, which are essential for effective process monitoring and control. Furthermore, we established that CO<sub>2</sub> off-gas analysis can be directly correlated with the pH value of the fermentation medium. This correlation allows for accurate pH prediction with comparable precision to traditional methods, where CO<sub>2</sub> levels are first determined via Raman spectroscopy or an off-gas analyzer and then used to infer pH through a correlation curve. In the final step of our study, we employed a Raman submers probe to predict CO<sub>2</sub> and pH directly within the fermentation medium. Compared to the model accuracy in the off-gas stream, the performance of the Raman submers probe in predicting CO<sub>2</sub> and pH within the medium was significantly worse, likely due to the absence of a pretrained model for CO<sub>2</sub>. Our findings highlight the potential of Raman off-gas spectroscopy as a powerful tool for real-time bioprocess monitoring and control, offering significant advantages in terms of accuracy and efficiency.
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spelling doaj-art-7cf281b3683f4795a66c6b0ccd3bb5362025-08-20T02:20:57ZengMDPI AGFermentation2311-56372025-06-0111631710.3390/fermentation11060317Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas StreamTobias Wallocha0Michaela Poth1Pharma Research and Early Development, Roche Diagnostics GmbH, 82377 Penzberg, GermanyPharma Research and Early Development, Roche Diagnostics GmbH, 82377 Penzberg, GermanyThe accurate measurement of CO<sub>2</sub> concentration in fermentation off-gas is crucial for monitoring and optimizing bioprocesses, particularly in mammalian cell cultures. In this study, we successfully utilized Raman off-gas spectroscopy to achieve time-resolved prediction of CO<sub>2</sub> concentrations in the fermentation off-gas. Our experiments were conducted using two different media: a commercial medium (medium 1) and an in-house Roche medium (medium 2), each tested with two different lots. The results demonstrated that Raman spectroscopy provides precise and real-time CO<sub>2</sub> measurements, which are essential for effective process monitoring and control. Furthermore, we established that CO<sub>2</sub> off-gas analysis can be directly correlated with the pH value of the fermentation medium. This correlation allows for accurate pH prediction with comparable precision to traditional methods, where CO<sub>2</sub> levels are first determined via Raman spectroscopy or an off-gas analyzer and then used to infer pH through a correlation curve. In the final step of our study, we employed a Raman submers probe to predict CO<sub>2</sub> and pH directly within the fermentation medium. Compared to the model accuracy in the off-gas stream, the performance of the Raman submers probe in predicting CO<sub>2</sub> and pH within the medium was significantly worse, likely due to the absence of a pretrained model for CO<sub>2</sub>. Our findings highlight the potential of Raman off-gas spectroscopy as a powerful tool for real-time bioprocess monitoring and control, offering significant advantages in terms of accuracy and efficiency.https://www.mdpi.com/2311-5637/11/6/317Raman spectroscopyRaman off-gas analysisoff-gas analyticCO<sub>2</sub> in bioprocessespHpH calculation via off-gas CO<sub>2</sub>
spellingShingle Tobias Wallocha
Michaela Poth
Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream
Fermentation
Raman spectroscopy
Raman off-gas analysis
off-gas analytic
CO<sub>2</sub> in bioprocesses
pH
pH calculation via off-gas CO<sub>2</sub>
title Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream
title_full Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream
title_fullStr Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream
title_full_unstemmed Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream
title_short Harnessing Raman Spectroscopy for Enhanced Bioprocess Monitoring: Predictive CO<sub>2</sub> Analysis and Robust pH Determination in Bioreactor Off-Gas Stream
title_sort harnessing raman spectroscopy for enhanced bioprocess monitoring predictive co sub 2 sub analysis and robust ph determination in bioreactor off gas stream
topic Raman spectroscopy
Raman off-gas analysis
off-gas analytic
CO<sub>2</sub> in bioprocesses
pH
pH calculation via off-gas CO<sub>2</sub>
url https://www.mdpi.com/2311-5637/11/6/317
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