The prior art method for lactoserum processing involves fermentation by two bacteria cultures, with one of them belonging to propionic bacteria, with subsequent extraction of protein. Under the new method, lactoserum is subsequently treated with lactobacillus casei and Propionibacterium freudenreichii cultures, and in this case the treatment by the second culture is performed with the lactoserum рн value reduction from the initial value at least by 0.8 units, at the moment of the second culture seed transfer the cultures proportion is maintained from 0.4 to 5.0 and total concentration of the cultures should be from 1 to 5 g/l of the medium.

Different versions of the new method are as follows:

2. Fermentation is carried out at 5-% saturation of the lactoserum with oxygen, minimum;
3. Nutrients are additionally added to the lactoserum;
4. While culturing, the lactoserum undergoes aeration;
5. Prior to fermentation the lactoserum is stripped to the 15 – 25-% content of dry agents.
6. The use is made of strain ГСБ-ТБ1Б;
7. The use is made of strain ВСБ-16;
8. The finished protein product is obtained in the form of concentrate or dry powder.