Broth rheology of Beta vulgaris cultures growing in an air lift bioreactor

Cell cultures of Beta vulgaris were developed in an air lift bioreactor of 10 dm3. Culture broth rheology exhibited non-Newtonian, shear thinning characteristics. The pseudoplasticity of the broth was governed by the presence of the cells as well as by the proteins secreted by the cells in the medium. The accumulation of extracellular proteins produced an increase in the viscosity and a change in the rheological properties of the cell-free medium. This phenomena may be a response of the cells to hydrodynamic stress. The accumulation of extracellular proteins and the change in the rheology of cell-free medium were discussed with respect to those data reported in literature obtained in shake flasks and stirred tank bioreactor.