Scale-up of citric acid fermentation by redox potential control

To obtain high citric acid productivity in Aspergillus niger fermentation on beet molasses substrate, a certain redox potential profile with two maxima (260 and 280 mV) and two minima (180 and 80 mV) must be maintained. The most effective regulation of redox potential is by regulation of aeration and agitation. It has been shown that control of redox potential by aeration and agitation is a most successful method for scale-up from 10-L laboratory scale to the 100- and 1000-L pilot-plant scale, even in geometrically dissimilar stirred-tank reactors. Copyright 1999 John Wiley & Sons, Inc.