Macroporous copolymer matrix IV. Expanded bed adsorption application

Macroporous crosslinked hydroxyethyl methacrylate-ethylene dimethacrylate c opolymeric beads (HEG beads) were synthesized by suspension polymerization in the presence of a pore generating agent. These beads were coupled to a-c yclodextrin through a urethane spacer. These modified copolymer beads (affi nity-HEG beads) so prepared were evaluated for their suitability in expande d bed chromatography. The optimum thickness of the distributor plate for st able expanded bed for use in expanded bed adsorption (EBA) was established. The affinity-MEG beads are comparable in density to Streamline diethyl ami no ethane (DEAE) and exhibit better mechanical stability at higher superfic ial velocity under fluidization. The affinity-MEG beads were used as affini ty chromatography matrices for the purification of cyclodextrin glycosyltra nsferase. Feeding of 5-fold diluted fermented broth to the column containin g affinity-MEG beads of settled bed height 7.5 cm (I.D. 26 mm and length 42 cm) at double bed expansion resulted in a sharp breakthrough curve of alph a -cyclodextrin glycosyltransferase (CGTase). The adsorbed enzyme was elute d from the bed in 50 mM Tris-HCl buffer containing 10 mM CaCl2 at 25 degree sC in packed bed configuration. (C) 2001 Elsevier Science BN. All rights re served.