RHEOLOGICAL AND MORPHOLOGICAL PROPERTIES OF SUBMERGED CITRIC-ACID FERMENTATION BROTH IN STIRRED-TANK AND BUBBLE-COLUMN REACTORS

Rheological data for beet molasses broth with Aspergillus niger in pellet form are reported for the biomass developed in a large number of experiments in a 50 1 bubble column reactor and a 5 1 stirred-tank reactor. The results are summarized in two typical time courses for batch fermentation. Morphological differences caused by the different shear fields in the two reactors are reflected in the rheological differences. The non-Newtonian properties of the whole fermentation broth depend entirely on the concentration and morphology of the biomass since the liquid phase is a low viscosity Newtonian fluid.