Selection criteria for defoamers used in fermentation

As a commonly used additive, defoamers come in a wide variety of types. However, how should we choose defoamers for fermentation when using them? Below, the editor of Jianyi Chemical will introduce several selection criteria for everyone!

1. Insoluble or insoluble in foaming solution

In order to break the foam, the defoamer should be concentrated on the foam film. For defoamers, they should be concentrated and concentrated in an instant, and for foam suppressants, they should be kept in this state regularly. So defoamers are in a supersaturated state in foaming liquids, and only insoluble or poorly soluble ones are prone to reaching supersaturation. Insoluble or difficult to dissolve, it is easy to aggregate at the gas-liquid interface, easy to concentrate on the bubble membrane, and can function at lower concentrations. The defoamer used in water systems, the active ingredient molecules, must be strongly hydrophobic and weakly hydrophilic, with an HLB value in the range of 1.53 for the best effect. Such as silicone defoamers or polyether defoamers.

2. Surface tension lower than foaming liquid

Only when the intermolecular forces of defoamers are small and the surface tension is lower than that of foaming liquids, can defoamer particles penetrate and expand on the foam film. It is worth noting that the surface tension of the foaming solution is not the surface tension of the solution, but the surface tension of the foaming solution.

3. Has a certain degree of affinity with foaming liquid

Since the defoaming process is actually a competition between the foam collapse speed and the foam generation speed, the defoamer must be able to disperse rapidly in the foaming liquid so that it can quickly play a role in a wider range of foaming liquid. To make the defoamer diffuse quickly, the active ingredient of the defoamer must have a certain degree of affinity with the foaming solution. The active ingredients of defoamers are too close to foaming liquids and will dissolve; Too sparse and difficult to disperse. Only when the closeness is appropriate can the effectiveness be good.

4. No chemical reaction occurs with foaming liquid

Defoamers react with foaming liquids, causing them to lose their effectiveness and potentially produce harmful substances that can affect microbial growth.

5. Low volatility and long duration of action