FED BATCH CULTURE OF SACCHAROMYCES-CEREVISIAE - PERSPECTIVE OF COMPUTER CONTROL TO ENHANCE PRODUCTIVITY IN BAKERS-YEAST CULTIVATION

A means to avoid the glucose effect in the production of baker''s yeast from glucose and/or molasses in a fed batch culture by controlling the feed rate of fresh medium with an ad hoc measurement of RQ is presented. The feed rate is changed stepwise such that the value of RQ ranges from 1.0-1.2 throughout the cultivation. Thus far, the specific growth rate based on the total cell mass and the growth yield obtained throughout are 0.24 h-1 and 0.55 g cell/g glucose. Prior to the experimental run, equations to predetermine the feed rate and concentration of glucose in the feed are derived from the mass balance of limiting substrates (glucose). Since values of RQ or IO2 (total O2 consumption rate) are measured quite easily and reliably, computer control of the fermentation is discussed.