Non-Invasive Optical Dissolved Oxygen Quantification in Small-Scale Bioreactors

Konstantin Schneider

IPT Issue 39 December 2011

Non-invasive quantification of dissolved oxygen using fluorescence-based optical sensors can be implemented in a vast variety of small-scale bioreactors, offereing several advantages over conventional electro-chemical quantification methods. Small-scale bioreactors such as microtitre plates and shake flasks, or small-scale continuous cultivation systems, are extensively used in industry and academia for both microbial biotechnology and cell culture technology since they offer the advantage of easy and relatively inexpensive parallelisation. However, small-scale bioreactors often lack the possibility of dissolved oxygen (DO) quantification in the reaction mixture. No - or only very little - attention is paid to the oxygen supply of the growing culture when using these cultivation systems since classical electro-chemical methods are usually not applicable in such small devices. Hence, oxygen limitation is one of the major problems in small-scale aerobic cultivation and is often neglected or simply overlooked, which could cause severe drawbacks with regard to scale up or reproducibility. Therefore, a reliable method for the determination of DO concentration in small-scale cultivation systems is needed.