Foam Control in Submerged Fermentation: State of the Art

Abstract

Foam, a dispersion of gas in liquid with bulk density approaching that of the gas, is an agglomeration of gas bubbles separated from each other by a thin liquid film. Foam formation is a common phenomenon in many industrial processes including chemical and fermentation processes. Its formation is a desirable property in some processes such as in the production of beer. However, foam in submerged fermentations poses a serious problem and results in the loss of material through the exhaust lines as well as the danger of contamination of the fermentation batch and the environment. The preferred method of foam control in fermentation is by the use of antifoam agents, although in a few instances, a mechanical foam breaker is used along with the chemical antifoam. In fermentations, the control of foam is a costly and nonproductive operation and therefore an effective foam control with reduced costs greatly influences the economics of the process.