| Abstract: | The gas–liquid oxygen transfer rate is a key step in the production of antibiotics in submerged fermentation. If the gas–liquid oxygen mass transfer rate is not equal to the required liquid–solid oxygen mass transfer rate at a particular cell concentration, then productivity of the particular fermentation operation will not be the maximum possible value. One way to increase the productivity of a given fermentation tank installation is to increase the cell concentration and to increase the oxygen transfer by changing the mixer and air supply to match the new requirements. In order to evaluate the cost of making this change to the larger mixing equipment, a typical cost example is given which can easily be modified for other combinations of production cost and mixer cost. As an example, it is seen that a considerable savings can result from a given installation by primarily changing the oxygen transfer ability of the equipment to utilize a given fermentor more efficiently. Production cost savings of 8 to 25% are shown in the example cited. |
