An airlift draft-tube fluidized bioreactor has been designed and tested for applications in protein bioseparation. Operating
parameters and geometrical dimensions of the bioreactor were optimized to ensure fluid circulation in a defined cyclic pattern
between the riser and the downcomer. The overall directionality of liquid flow generates homogeneous field of low shear and
achieves good mixing efficiency. Bioseparation of proteins was achieved from solutions containing both BSA and BHb at different
initial concentrations and at pH 7. Similar adsorption capacities of both proteins were observed in single protein adsorption
experiments at pH 7. Compressibility of BHb allowed for high adsorption capacity, in addition to the hydrophobic interaction
forces. Apparently the homogeneous and lower shear generated by the airlift bioreactor reduces the compressibility of adsorbed
BHb. This allowed for higher BSA adsorption from solutions containing BSA and BHb mixtures. Conventional batch adsorption
experiments showed more adsorption of BHb, which reduces bioseparation efficiency.
Keywords Airlift bioreactors - Protein adsorption - Bioseparation - Gas hold-up - Bioprocess design