Thermal and ultrasound foam control in biotechnology: a mini-review

Abstract

Gas, which is trapped in either solid or liquid pockets, results in foam formation. Foam formation is common in many industries, i.e., in detergents, food and beverage, cosmetics, and fire-fighting. Foam formation in excess causes biotechnology fermentation instabilities, including material loss and the danger of contaminating the fermentation and the environment. Many foam-controlling measures have been reported, including thermal, enzymatic, mechanical, ultrasound pretreatments, steam explosion, reducing digester mixing, and surface sludge spray. Using antifoaming agents for foam control in fermentation is the most common method, sometimes supported by mechanical foam breakers. However, antifoam can be costly and can complicate product purification. Indeed, effective foam control can significantly impact the economics of the whole process. This mini-review summarizes some unconventional foam destruction techniques, including their various challenges.