P32: Initial Characterization of a Novel Luminescent Oxygen Probe and its Use in Bioreactor Applications

A novel optical oxygen sensing film has been developed by Michigan State University that has distinct performance advantages over current commercial luminescent sensing technologies.  These include the lack of photobleaching, which enables unlimited sampling over prolonged periods of time, chemical stability in various aqueous solutions and rapid response.  A probe suitable for fermentation applications was tested in a continuous Saccharomyces cerevisiae culture.  The output of the optical sensor was compared with the standard polarographic probe in the bioreactor.  We report on two different experiments.  For the first experiment, the DO concentration was measured every 12 sec for a four day period.  The feed/flow conditions in the bioreactor were randomly varied to test the optical sensor response over the entire DO range from 0 to 100% saturation.  In the second experiment sustained 10 min oscillations between periods of high respiration (low DO₂ content) and low respiration (high DO₂ content) were established in the aerobic S. cerevisiae culture.  The optical probe faithfully tracked the oscillations for three days, at the data rate of 1 data point every 5 sec. The data was analyzed by Fast Fourier transform (FFT) to determine periodicity.  The poster will demonstrate the use of the novel optical dissolved oxygen sensor in lab scale bioreactors along with a preliminary evaluation of the capabilities of the sensor in comparison to the typically employed electrochemical DO₂ probe.