Some Modifications to Dawson's Continuous Cyclone Column Culture Apparatus

Summary Alternatives to Dawson's pneumatic levelling device have been devised so that the machine can be operated without loss of volatile substances from substrate or end product. The cyclone column has been modified by adding a side arm on which is fixed a level sensing device. Two methods for sensing the liquid level are described. The first is a light‐beam/phototransistor system actuated by the rise and fall of a float; the second is a device capable of sensing a change in capacitance caused by movement of the liquid towards or away from a sensing probe. Either of these systems can be linked to a pump controlling the inflow of fresh medium. The manufacture of Fino sherry was chosen as an example of a process with a volatile substrate and end product because it involves the partial oxidation of ethanol to acetaldehyde by a Flor yeast.