Use of Fluorometry for On-Line Monitoring and Control of Bioreactors — Microbial Cell Concentration and Activity, Plant Cell Metabolism, Mixing Time, and Gas Hold-up

On-line monitoring and control of bioprocesses is one of the most challenging research areas in biochemical engineering. Sterilizable dissolved oxygen (DO) and pH probes have been available since the 1960s. No other biosensors developed since then have proved to be as good as the DO and pH probes. Dissolved oxygen, pH and temperature along with off-gas analysis are the only parameters which are monitored on-line in industrial fermentations. None of the present on-line measurement techniques involves intracellular parameters. This limitation has hampered the development of bioprocess control since our ability to control and perform on-line optimization of fermentation processes is limited by our ability to monitor what is happening in the fermentation.