Studies on protein production by yeasts. IV. Incremental feeding modulus

S. cerevisiae Gr. 104 which seemed to be the most efficient strain in protein production, was used for investigating its optimum incremental feeding modulus that gives the highest economical yield. Therefore, different hourly rates of incremental feeding, ranging from 1.14 to 1.22, were used and the yeast yield for each rate was determined. Experiments were carried out in a laboratory fermentor vessel of 5 liter capacity, using molasses, ammonium sulphate, and potassium dihydrogen phosphate as feeding substances with optimum pH, temperature, and effective aeration. The optimum incremental feeding for this strain (which is the rate of molasses feeding corresponding to the exponential growth rate) was found to be 1.18. At this rate the best economical use of the substrate was obtained with the production of yield, close to the theoretically calculated yield.