Ultrasound-Particle Manipulation for in-line Characterization of Cells with Raman and ATR-FTIR Spectroscopy in a Bioreactor
Focus area / active in:
- New tools/instruments for the bio-based industry
- Raman spectroscopy
- in-line sensors
- ultrasound particle manipulation
- ultrasonic trap, cyanobacteria
- process control
The exact characterization of the physiological state of cells (particles) during a fermentation (or similar processes) enables a highly accurate process control. For this purpose, it requires selective and non-destructive analytical methods that can be used in-line and provide the necessary depth of information, such as Raman and infrared spectroscopy. However, these techniques do not offer the possibility to differentiate in-line between the medium and particulate parts, such as cells, or often do not have sufficient sensitivity. This can be changed by using an ultrasonic trap. Ultrasonic fields can exert forces on particles so that they can be trapped at a certain location and then be moved by a specific arrangement of the field. This allows the construction of U.S. process fittings that allow spectroscopic in-line sensors to bring particles (cells) to their sensitive point. This way they can be measured sensitively. Conversely, the measuring volume can also be kept particle-free, which enables interference-free measurement of the medium. The advantages are shown here with two examples: the in-line characterization of yeast cells and the storage of PHB and glycogen in cyanobacteria during fermentation. A typical application of an ultrasonic process fitting (2) in a bioreactor (1). The probe (3) forms an ultrasonic trap (7) with the sound generator (4), with the help of which particles, such as cells, can be brought into the focus point (6) of the probe or kept away. This enables a sensitive and selective measurement of medium and suspended particles directly in the process.
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