Foaming in submerged citric acid fermentation on beet molasses

Summary Foam control is an important part of every fermentation technology. Chemical anti-foam agents (AFA) are surface active substances, which decrease the surface elasticity of liquids and prevent metastable foam formation. Most AFA must be mixed or dissolved in a suitable carrier substance if their antifoaming properties are to be fully utilized. The carrier seems to act as a reservoir from which the AFA is liberated.The toxicity of different AFA upon Aspergillus niger was tested in Petri dishes. Their effect on the decrease of the respiration ability of the test organism A. niger was tested in a Warburg apparatus. Various AFA were tested as pure substances, as emulsions in seed oil and as mixtures of different AFA in cylindrical vessels with sinter glass discs under similar conditions as in the fermentor. Using mentioned methods the most suitable AFA were tested in citric acid fermentation on beet molasses.Partly presented at the poster session of the meeting: Fungal Biotechnology, Glasgow, September 1978