Foaming during a fermentation may result in the loss of broth, cells and product via the air outlet as well ■ nutting the fermentation at risk from contamination (see Chapter 9). Thus, foaming is normally controlled hv cither chemical or mechanical means (see Chapters 4 and 7), hut this task may be made easier if a non-foaming strain of the commercial organism can be developed. Foaming which occurs early in the fermentation is usually due to a component in the medium whereas foaming late in the fermentation is normally a property of the growing organism and, therefore, it is only this latter type of foam which may be controlled by strain selection. Both mutant screening and recombination may be used to develop non-foaming types but, obviously, the organisms must be tested for productivity as well. Recombination appears to be a particularly attractive proposition especially if non-foaming mutants have been isolated which are poor producers or good producers which foam. Ancestral crosses using protoplast fusion techniques may then render a strain combining the desirable features of both strains.
Was this article helpful?
Discover How To Become Your Own Brew Master, With Brew Your Own Beer. It takes more than a recipe to make a great beer. Just using the right ingredients doesn't mean your beer will taste like it was meant to. Most of the time it’s the way a beer is made and served that makes it either an exceptional beer or one that gets dumped into the nearest flower pot.