In recent years there has been a considerable interest in developing membrane chromatography systems that function as a short, wide chromatographic column in which the adsorptive packing consists of one or more microporous membranes. This study reports the use of new adsorber membranes prepared by the incorporation of various types of ion exchange resins into an EVAL porous membrane for protein recovery. The obtained heterogeneous matrixes composed of solid particles surrounded by the polymeric film possess a good accessibility for the protein to the adsorptive sites. Furthermore, small particles can be embedded into porous polymeric structures without the disadvantages of classical chromatographic columns (high pressure drop, fouling and plugging sensitivity, low flow rate), but with the advantages of membrane technology (easy scale-up, low-pressure drop, high flow rate). The adsorptive membranes feature high static as well as dynamic protein adsorption capacities for operating flow rates ranging from 200 to 400 L h bar per m(2) and ionic strength of 20 - 200 mM. In a sequential desorption step by changing the pH and/or the ionic strength of the eluent, up to 90% protein recovery was obtained. Next to the separation, the mixed matrix adsorber membrane functions as a concentration medium since the protein can be concentrated up to 20-fold in the eluent. The adsorber membranes can be reused in multiple adsorption/desorption cycles with good adsorption performances. (C) 2003 Wiley Periodicals, Inc.