The development of a process intensified primary capture step for the direct selective recovery of intracellular proteins from very dense particulate-containing yeast extract has been explored. The purification of glyceraldchyde 3-phosphate dehydrogenase from bakers' yeast was chosen as a potential demonstration of this approach. A high throughput (50% w/v, yeast extracts at a superficial linear velocity of 450 cm h(-1)) was achieved by adoption of a high-density adsorbent (UpFront steel agarose: rho = 2.65 g ml(-1)) derivatized with selective ligand chemistries (Cibacron Blue 3GA). This should ultimately minimize adsorption time and maximize process efficiency of fluidized bed adsorption. (c) 2005 Elsevier Inc. All rights reserved.