Liquid Fluidized Bed Adsorption of Protein in the Presence of Cells

The adsorption, in a liquid fluidized bed, of Bovine Serum Albumin (BSA), onto an ion-exchange absorbent, Q-Sepharose Fast Flow, in the presence of Alcaligenes eutrophus cells, has been studied. The expansion of the fluidized bed is greater in the presence than in the absence of cells and obeys the laws of Richardson and Zaki. The effect of cell concentration on the equilibrium adsorption characteristics of the adsorbent has been assessed. The rate of adsorption of BSA onto the adsorbent has been studied in a batch stirred tank, and a fluidized bed system both in the presence and absence of cells. Comparisons have been made with the adsorption of human immunoglobulin G (human IgG), onto an affinity adsorbent, Protein A Sepharose CL-4B. The data from the fluidized bed breakthrough tests have been used to assess the validity of a theoretical model adapted from one that predicts the performance of the adsorption phase in the absence of cells in fixed bed systems. Tests have been done on the washing phase in the fluidized bed adsorption system to establish the most efficient method of washing cells and unadsorbed protein out of the bed.