Marco Scheidle, Johannes Klinger, Jochen Büchs:
Combination of on-line pH and oxygen transfer measurement in shake flasks by Fiber Optical Technique and Respiration Activity Monitoring System (RAMOS)
Sensors, 2007, 7(1), 3472-3480
Abstract: Shake flasks are commonly used for process development in biotechnology industry. For this purpose a lot of information is required from the growth conditions during the fermentation experiments. Therefore, Anderlei et al. developed the RAMOS technology [1, 2], which proviedes on-line oxygen and carbondioxide transfer rates in shake flasks. Besides oxygen consumption, the pH in the medium also plays an important role for the successful cultivation of micro-organisms and for process development. For online pH measurement fiber optical methods based on fluorophores are available. Here a combination of the on-line Oxygen Transfer Rate (OTR) measurements in the RAMOS device with an on-line, fiber optical pH measurement is presented. To demonstrate the application of the combined measurement techniques, Escherichia coli cultivations were performed and online pH measurements were compared with off-line samples. The combination of on-line OTR and pH measurements gives a lot of information about the cultivation and, therefore, it is a powerful technique for monitoring shake flask experiments as well as for process development.
fiber optical pH measurement, shaking flask, oxygen transfer rate, RAMOS, E. coli, process development