Controlled supply of trace amounts of oxygen in laboratory scale fermentations

A detailed study of anaerobic yeast fermentations requires controlled addition of minor amounts of oxygen to the fermentor. A method for supplying small‐scale fermentations with millimolar amounts of oxygen is described. The controlled addition is accomplished by diffusion of oxygen through silicone tubing carrying nitrogen to the fermentor. Sulfite values of the fermentation system are given for different gas velocities and lengths of silicone tubing. Two experiments are outlined in which this technique is applied and the possible energy yield from oxydative phosphorylation is discussed.