Out-of-phase operating conditions, a hitherto unknown phenomenon in shaking bioreactors
✍ Scribed by Jochen Büchs; Stefan Lotter; Claudia Milbradt
- Book ID
- 104419624
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 438 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1369-703X
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✦ Synopsis
One of the important parameters in characterising fermentations of aerobic microorganisms is the specific power consumption. A new method has been introduced which enables the accurate determination of the power consumption in shaking bioreactors. It is based on torque measurements in the drive and the appropriate compensation of the friction losses. Measurements of the power consumption revealed the phenomenon of the liquid being 'out-of-phase' for the first time for shaking bioreactors. This occurs at certain operating conditions and is characterised by an increasing amount of liquid not following the rotating movement of the shaker table, thus reducing the specific power consumption, mixing and the gas/liquid mass transfer. With respect to this, different hydrodynamic cases have to be distinguished. All these cases have in common, however, that the probability of 'out-of-phase' conditions increases with lower shaking diameters, lower filling volumes, larger number and sizes of baffles and higher viscosity. For unbaffled flasks with a nominal volume