title: Comparison of two methods for designing calorimeters using stirred tank reactors.
abstract: Calorimetry is a robust method for online monitoring and controlling bioprocesses in stirred tank reactors. Up to now, reactor calorimeters have not been optimally constructed for pilot scale applications. Thus, the objective of this paper is to compare two different ways for designing reactor calorimeters and validate them. The "heat capacity" method based on the mass flow of the cooling liquid in the jacket was compared with the "heat transfer" method based on the heat transfer coefficient continuously measured in the cultivation of Escherichia coli VH33 in a 50 L stirred tank reactor. It was found that the values of the "heat transfer" method agreed very well with the calculated values from the oxygen consumption. By contrast, the curve of the "heat capacity" method deviated from that of the oxygen consumption calculated with the oxycaloric equivalent. In conclusion, the "heat transfer" method has been proven to have a higher degree of validity than the "heat capacity" method. Thus, it is a better and more robust means to measure heat generation of fermentations in stirred tank bioreactors on a pilot scale.
authors: RWTH Aachen, AVT-Biochemical Engineering, Worringer Weg 1, 52056 Aachen, Germany.
authors: Lars
authors: L
authors: Regestein
authors: Heiner
authors: H
authors: Giese
authors: Michael
authors: M
authors: Zavrel
authors: Jochen
authors: J
authors: Büchs
mesh_terms: D061249:Batch Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods*; D019149:Bioreactors; D001709:Biotechnology / Q000295:instrumentation*; D002138:Calibration; D002151:Calorimetry / Q000295:instrumentation*; D004867:Equipment Design; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D005285:Fermentation; D015203:Reproducibility of Results; D013696:Temperature; D019415:Torque