摘要 |
The bubbling of poorly soluble gases into fermentation liquids either for the replenishment of dissolved oxygen or for removal of excess super-saturated CO2 can lead to severe foaming problems, particularly in deep fermentation vessels. The present invention overcomes this problem by dissolving the gas in an aqueous medium, usually water, under superatmospheric conditions and injecting the gas solution into the fermentation liquid in controlled quantities under conditions such that the gas is either retained in solution in the fermentation liquid or, at most, the gas is released from solution in the form of microbubbles of much smaller size than can be obtained by passing gas through a porous diffuser. Microbubbles may be released from the gas solution by injecting the pressurized gas solution into the fermentation liquid under conditions of high shear rate.
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