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Vorträge und Posterpräsentationen (mit Tagungsband-Eintrag):

C. Koch, C. Herwig, B. Lendl:
"In-line monitoring of trehalose in yeast using an ultrasound enhanced mid-IR fiber optic sensor";
Hauptvortrag: 27th Yeast Conference, Istanbul; 14.04.2014 - 15.04.2014; in: "Proceedings of the 27th Yeast Conference", Editor Versuchsanstalt der hefeindustrie e.V., (2014), S. 177 - 188.



Kurzfassung englisch:
This paper reports on the development and application of an ultrasound enhanced mid-IR fiber optic sensor for in-line bioprocess monitoring. Mid-IR spectra contain direct, molecular specific information which can be used for qualitative and quantitative analysis. The developed sensor improves the current state-of-the-art in mid-IR based in-line process monitoring as it is capable of recording and distinguishing between mid-IR spectra from solutes (e.g. nutrients or products) and microorganism (e.g. yeast). This is made possible by using a sensor which employs a planar attenuated total reflection (ATR) element and by combining it with ultrasound technology in the MHz frequency range. Using the ATR technique only the sample in close vicinity (1-3 µm) of the ATR surface does contribute to the recorded spectra. The MHz ultrasound is generated by a piezo-ceramic element which is placed at a distance of a few millimetres away from the ATR surface. When the sound is turned on a standing MHz sound wave is generated between the ATR surface and the sound source. In such a standing MHz wave pressure nodal planes are formed which represent minima of potential energy. Thus when the sensor is placed in a bio-suspension and the sound is turned on, microorganisms will be captured in the nodal planes. By changing the sound frequency the positions of the nodal planes shift thus enabling manipulation of the microorganism trapped therein. In this way they can be either kept away from the ATR sensor surface allowing only the measurement of solutes, or alternatively microorganism can be pressed against the ATR surface so that their mid-IR spectra can be recorded.
We have applied this sensor technology for in-line monitoring of yeast fermentations where changes in the chemical composition of the yeast could be detected. In particular the sensor provided real-time insight in changes of the carbohydrate content of yeast as based on the recorded mid-IR spectra trehalose, glycogen and mannose can be discriminated. Off-line analysis of yeast for their carbohydrate concentration by standard methods confirmed the results provided by mid-IR spectroscopy.

Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.