MEASUREMENT OF DISSOLVED CARBON-DIOXIDE

Several probes for measuring dissolved CO2 concentration were installed in a 68 l fermentor and their effectiveness compared. Submerged silastic rubber tubing gave reproducible results over a wide range of operating conditions and was generally superior to all other probes evaluated. The silastic rubber probe was used to compare the partial pressure of CO2 in viscous fermentation media with that in the fermentor exhaust gas. No significant difference was found. Determination of the CO2 partial pressure in the exhaust gas gives an excellent approximation of the partial pressure of dissolved CO2 in the liquid medium, eliminating the need for measurement of CO2 concentration in the broth. [Streptomyces fradiae fermentation of antibiotics was studied but the results are probably applicable to a wide range of industrial microbial fermentations.].