Enhanced performance of expanded bed chromatography on rigid superporous adsorbent matrix

Rigid spherical macroporous adsorbent beads with surface hydroxyl groups we re prepared by cross-linking of cellulose. These bends had diameter in the range 100-200 mu m and a mean pore size of about 3 mu m with about 60% pore volume. The matrix (bulk density similar to 1600 kg m(-3)) could be expand ed into a stable bed and used for protein chromatography. Chromatographic r uns were performed on a 10 mm diameter column under non-retaining and retai ning conditions on the prepared matrix (called Celbeads) and performance of the runs was measured in terms of the height equivalent to a theoretical p late (HETP). The HETP curves in both packed and expanded bed modes followed profiles typical of macroporous adsorbents, i.e. increasing and levelling with velocity. Unimpaired performance of the matrix at increasing flow-rate s permitted expanded bed elution of adsorbed solutes without loss of effici ency in terms of purification factor and product concentration. As a model system, Celbeads was used to purify lactate dehydrogenase from porcine musc le homogenate by dye-affinity chromatography. The prepared matrix provided about 100 theoretical plates per meter for the enzyme system at a linear fl ow velocity of 1.27 cm min(-1) in an expanded bed elution mode, and gave en zyme yields of 100% with a purification factor of 31 using an optimized pro cedure. The adsorbent could be cleaned in place with 5 M urea and used repe atedly without loss of performance. (C) 2000 Elsevier Science B.V. All righ ts reserved.