We evaluated the feasibility of using immobilized metal-ion affinity chromatography (IMAC) with nickel ion complexed with Tris(2-aminoethyl)amine (TREN) immobilized on agarose gel for purification of human Fab fragments by negative chromatography. Efficient purification of Fab fragments from digested human IgG (immunoglobulin G) (106.4% purity) was accomplished in Tris-HCI buffer at pH 7.5 without NaCI (based on total protein concentration and radial immunodiffusion of human Fab). A teChnological application of Ni(II)-TREN-agarose using non transgenic soybean protein extract spiked with human Fab fragments as feedstream was also studied. Experiments using Tris-HCI at pH 7.0 as loading buffer allowed the adsorption of almost all of the soybean proteins. Sixty-six percent of the loaded human Fab fragments were recovered in the flowthrough and washing fractions with about 90% purity. These results demonstrate that Ni(II)-TREN-agarose is a potential adsorbent for recombinant Fab fragment purification. (C) 2014 Published by Elsevier Ltd.