Application of a statistical technique to the production of Saccharomyces cerevisiae (baker's yeast)

The identification of a static model for Saccharomyces cerevisiae (baker's yeast) production under aerobic conditions has been realized. Two-level factorial experimental design was used to identify a statistical model. In order to find the optimal operating conditions by using the statistical model, Box-Wilson's steepest-ascent method was used [Box and Wilson (1951) J. R. Stat. Soc. Ser. B 13, 1]. Four independent variables which have an effect on aerobic yeast production were selected. These were temperature, pH, air flow rate and agitation rate. Yeast productivity was selected as the dependent variable. A first-order statistical model was considered to illustrate the dependence of the yeast productivity on the operating parameters. Optimum pH, temperature, air flow rate and agitation rate were determined as 5, 32 degrees C, 1 vol./vol. per min and 600 rev./min respectively.