The immobilization of proteins is an essential step in constructing affinity purification or enzyme reactor systems. For these biotechnological processes, immobilized proteins can be used in either batchwise or column operations. Commonly utilized insoluble supports for protein immobilization are beads of crosslinked gels of agarose, dextran, or synthetic polymers. When used in a batchwise mode, the beads are not easy to handle (harvesting, and so on). When used in a packed column, loosely crosslinked gels may exhibit structural instability under high pressure conditions (1 ), thus failing to produce high flow rates desired by biotechnological processes. Highly crosslinked gels, although structurally more stable, may exhibit lower degrees of protein immobilization within the interior of the beads, thereby reducing the reactor surface area. As an immobilization support, cellulose fibers are much less expensive than crosslinked gels and they possess a large surface area allowing for high protein loading. The fibers, however, are compressible and do not yield high flow rates when compressed into random configurations.
