Lecture
Inline Bioprocess Monitoring by Photon Density Wave Spectroscopy
- at -
- ICM Saal 3
- Type: Lecture
Lecture description
Dr. Roland Hass
Photon Density Wave (PDW) spectroscopy [1] is a calibration-free approach for the simultaneous, absolute, and independent quantification of the optical absorption coefficient and the reduced scattering coefficient of highly light scattering liquids as they are often found in biotechnical processes. The virtues of PDW spectroscopy for inline process monitoring are found in its applicability to concentrated systems, systems under stirring or under flow and/or higher viscosity, time resolution in the subminute regime, limited issues with so-called process probe fouling, and a background entirely based on theoretical descriptions.
The development of Photon Density Wave (PDW) spectroscopy over the last 20 years is discussed – from electro-optic individual components to an integrated fiber-optical, probe-based process analytical technology. Furthermore, biotechnical application examples are reviewed, covering the high cell density cultivation of Scenedesmus rubescens, Escherichia coli, and Ralstonia eutropha as well as enzymatic milk and beer mash conversations.
Literature:
[1] Schiewe, T., Koenig, A.J., Weiske, B. et al. Photon density wave spectroscopy as process analytical technology: a review of recent advances in technology and application. Anal. Bioanal. Chem. 418, 35–54 (2026). https://doi.org/10.1007/s00216-025-06200-8.
Photon Density Wave (PDW) spectroscopy [1] is a calibration-free approach for the simultaneous, absolute, and independent quantification of the optical absorption coefficient and the reduced scattering coefficient of highly light scattering liquids as they are often found in biotechnical processes. The virtues of PDW spectroscopy for inline process monitoring are found in its applicability to concentrated systems, systems under stirring or under flow and/or higher viscosity, time resolution in the subminute regime, limited issues with so-called process probe fouling, and a background entirely based on theoretical descriptions.
The development of Photon Density Wave (PDW) spectroscopy over the last 20 years is discussed – from electro-optic individual components to an integrated fiber-optical, probe-based process analytical technology. Furthermore, biotechnical application examples are reviewed, covering the high cell density cultivation of Scenedesmus rubescens, Escherichia coli, and Ralstonia eutropha as well as enzymatic milk and beer mash conversations.
Literature:
[1] Schiewe, T., Koenig, A.J., Weiske, B. et al. Photon density wave spectroscopy as process analytical technology: a review of recent advances in technology and application. Anal. Bioanal. Chem. 418, 35–54 (2026). https://doi.org/10.1007/s00216-025-06200-8.
