Physiological Effects of Fermentation Defoamer on Cells
Defoamer has an important effect on the physiology of cells. The amount of defoamer should be reduced as much as possible. Before the antifoam should be used, a comparative experiment should be carried out to find out the microbial physiological characteristics of the silicone antifoams in the known medium. The conditions with the least impact and the maximum defoaming efficiency should consider the cost of the anti-foaming agent and the effect on the final product.
Defoamers has an effect on the yield, the general principle of fermentation is a small number of times!
During the fermentation process, due to the large amount of foam formation, the bacteria and foam form a stable emulsion, which affects the transmission of oxygen.
This is to add an appropriate amount of antifoam to eliminate the foam is beneficial to dissolved oxygen. However, the defoaming agent is added too much at one time, and the defoaming agent will accumulate on the surface of the microbial cells and the foam liquid film, increasing the mass transfer resistance and greatly reducing the oxygen transfer rate.
A small number of times is an important principle of AF flow, which cannot be added because it will affect production.
The reason is 1: too much antifoams will increase the resistance of the liquid film to affect the dissolution of oxygen and other substances that affect the transfer; 2: Some defoamers are toxic.
First of all, the relationship between foam and dissolved oxygen (DO), how the oxygen is transferred in the fermentation, is based on foams, therefore, the foam is more sure that the dissolved oxygen is high. Of course, the foam is high and there are other problems. In addition, the defoaming agent is added, because the foam is broken, the dissolved oxygen transmission is affected, and the DO will of course fall immediately. This is common sense, and it is actually the same.
The growth and decline of foam is regular, easy to produce, always occurs at a certain time, and in most cases, it is eliminated by adding antifoaming agent. In other cases, in the middle and late stages, the increase in foam is caused by the self-fusion of the cells. At this time, the single defoamers does not help. The reasonable method is to supplement the nutrients and make the cells. The growth of the growth is maintained, while the oxygen consumption is increased, and the growth of the foam is also controlled to some extent.