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Öğe Affinity separation of plasma proteins using a newly synthesized methacrylamidoalanine incorporated porous pHEMA membranes(Marcel Dekker Inc, 2002) Yavuz, H.; Patir, S.; Say, R.; Arica, Y.; Denizli, A.In this study, we synthesized a novel adsorbent to obtain high protein-adsorption capacity utilizing 2-methacrylamidoalanine (MAAL) containing membrane. Amino acid-ligand MAAL was synthesized by using methacrylochloride and alanine. Then, poly(2-hydroxyethylmethacrylate-co-2-methacrylamidoalanine) [p(HEMA-co-MAAL)] membranes were prepared by UV-initiated photopolymerization of HEMA and MAAL in the presence of an initiator (azobisisobutyronitrile, AIBN). Synthesized MAAL was characterized by nuclear magnetic resonance spectroscopy. p(HEMA-co-MAAL) membranes were characterized by swelling studies, porosimeter, scanning electron microscopy, Fourier transform-infra red spectroscopy, and elemental analysis. These membranes have macropores in the size range 5-10 mum. Different metal ions including Zn(II), Ni(II), Co(II), and Cu(II) were chelated on these membranes. p(HEMA-co-MAAL) were used in the adsorption of human serum albumin (HSA) from aqueous media containing different amounts of albumin (0.1-5.0 mg L-1) and at different pH values (4.0-8.0). The maximum HSA adsorption was observed at pH 5.0. The nonspecific adsorption of HSA on the pHEMA membranes was negligible 0.9 mug cm(-2). MAAL incorporation significantly increased the HSA adsorption (1.76 mg cm(-2)). The HSA adsorption capacities of the metal-incorporated membranes were Greater than that of the p(HEMA-co-MAAL) membranes under the same conditions. Higher HSA adsorption capacity was observed from the human plasma (2.88 mg HSA cm(-2)).Öğe Biosorption of cadmium(II), lead(II) and copper(II) with the filamentous fungus Phanerochaete chrysosporium(Elsevier Sci Ltd, 2001) Say, R.; Denizli, A.; Arıca, M.Y.The biosorption from artificial wastewaters of heavy metals (Cd(II), Pb(II) and Cu(II)) onto the dry fungal biomass of Phanerochaete chryosporium was studied in the concentration range of 5-500 mg 1(-1). The maximum absorption of different heavy metal ions on the fungal biomass was obtained at pH 6.0 and the biosorption equilibrium was established after about 6 h. The experimental biosorption data for Cd(II), Pb(II) and Cu(II) ions were in good agreement with those calculated by the Langmuir model. (C) 2000 Elsevier Science Ltd. All rights reserved.Öğe Comparison of adsorption performances of metal-chelated polyamide hollow fibre membranes in lysozyme separation(Elsevier Science Bv, 2002) Şenel, S.; Kassab, A.; Arıca, Y.; Say, R.; Denizli, A.Commercially available microporous polyamide hollow fibres are modified by acid hydrolysis to activate the reactive groups and subsequently binding of the ligand, i.e. Cibacron Blue F3GA. Then the Cibacron Blue F3GA-derived hollow fibres were loaded with different metal ions (i.e. Zn(II), Cu(II), Ni(II)) to form the metal chelate. The internal polymer matrix was characterised by scanning electron microscopy. The effects of pH, initial concentration of lysozyme, metal type and temperature on the adsorption of lysozyme to the metal-chelated hollow fibres were examined in a batch reactor. The non-specific adsorption of lysozyme onto the polyamide hollow fibres was 1.8 mg/g. Cibacron Blue F3GA immobilisation increased the lysozyme adsorption up to 62.3 mg/g. Metal-chelated hollow fibres showed a significant increase of the adsorption efficiency. Lysozyme adsorption capacities of Zn(II), Cu(II) and Ni(Il)-chelated hollow fibres were different. The maximum capacities of Zn(II), Cu(II) or Ni(Il)-chelated hollow fibres were 144.2, 75.2 and 68.6 mg/g, respectively. Significant amount of the adsorbed lysozyme (up to 97%) was eluted in 1 h in the elution medium containing 1.0 M NaSCN at pH 8.0 and 25 mM EDTA at pH 4.9. Repeated adsorption-desorption process showed that this novel metal-chelated polyamide hollow fibres are suitable for lysozyme adsorption. (C) 2002 Published by Elsevier Science B.V.Öğe Heavy metal separation capacity of a porous methacrylamidophenylalanine containing membrane based on a polyhydroxyethyl methacrylate matrix(Marcel Dekker Inc, 2001) Denizli, A.; Say, R.; Patir, S.; Arica, Y.The abilities of various sorbent materials for heavy metal removal have been reported in the literature. We have developed a novel approach to obtain high metal-sorption capacity utilizing a membrane containing 2-methacrylamidophenylalanine. Metal-complexing ligand 2-methacrylamidophenylalanine (MAPA) was synthesized through the use methacrylo chloride and phenylalanine. Then, poly(2-hydroxyethyhmethacrylate-co-2-methacrylamidophenylalanine) (p(HEMA-co-MAPA)) membranes were prepared by UV-initiated photopolymerization of HEMA and MAPA in the presence of the initiator azobisisobutyronitrile. MAPA monomer was characterized by nuclear magnetic resonance spectroscopy. p(HEMA-co-MAPA) membranes were characterized by swelling studies, scanning electron microscopy, Fourier transform infrared spectroscopy, and elemental analysis. These membranes have large pores; the micropore dimensions are approximately 5-10 mum. p(HEMA-co-MA-PA) affinity membranes with a swelling ratio of 133.2% and containing 18.9 mmol MAPA/m(2) were used in the removal of the heavy-metal ions of copper, nickel, and mercury from aqueous media containing different amounts of these ions (5-600 mg/L) and at different pH values (2.0-7.0). The maximum adsorption capacities of heavy metal ions onto the MAPA-containing membranes under noncompetitive conditions were 23.8 = mmol/m(2) for Cu(II), 29.1 mmol/m(2) for Ni(II), and 50.3 mmol/m(2) for Hg(II). The affinity order was Hg(II) > Ni(II) > Cu(II). The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at approximately pH 5.0. Adsorption of heavy metal ions from artificial wastewater was also studied. The adsorption capacities were 11.9 mmol/m(2) for Cu(II), 7.33 mmol/m(2) for Ni(II), and 9.79 mmol/m(2) for Hg(II). Desorption of heavy metal ions was performed using 0.1 M HNO3. The p(HEMA-co-MAPA) membranes are suitable for more than five cycles without noticeable loss of capacity.Öğe Poly(hydroxyethyl methacrylate-co-methacrylamidoalanine) membranes and their utilization as metal-chelate affinity adsorbents for lysozyme adsorption(Vsp Bv, 2002) Garipcan, B.; Say, R.; Patir, S.; Arica, Y.; Denizli, A.Different adsorbents have been reported in the literature for protein purification. The authors have developed a novel and new approach to obtain high protein adsorption capacity utilizing a 2-methacrylamidoalanine-containing membrane. Amino acid ligand 2-methacrylamidoalanine (MAAL) monomer was synthesized using methacryloyl chloride and alanine. Poly(2-hydroxyethylmethacrylate-co-2-methacrylamidoalanine) [p(HEMA-co-MAAL)] membranes were then prepared by UV-initiated photopolymerization of HEMA and MAAL in the presence of an initiator (azobisisobutyronitrile, AIBN). The synthesized MAAL monomer was characterized by NMR. p(HEMA-co-MAAL) membranes were characterized by swelling studies, porosimeter, SEM, FTIR, and elemental analysis. These membranes have macropores in the size range of 5-10 mum. Cu(II) ions (25.9 mmol/m(2)) were chelated on these membranes. p(HEMA-co-MAAL) membranes were used to study the adsorption of lysozyme from aqueous media containing different amounts of lysozyme (0.1-3.0 mg/l) and at different pH values (4.0-8.0). The non-specific adsorption of lysozyme on the pHEMA membranes was negligible (0.9 mug/cm(2)). Incorporation of MAAL increased the lysozyme adsorption significantly up to 2.96 mg/cm(2). The lysozyme adsorption capacity of the Cu(II) incorporated membranes (9.98 mg/cm(2)) was greater than that of the p(HEMA-co-MAAL) membranes. More than 90% of the adsorbed lysozyme was desorbed in I h in the desorption medium containing 1.0 M NaCl and 0.025 M EDTA. The metal-chelate affinity membranes are suitable for repeated use for more than ten cycles without a noticeable loss of capacity.Öğe Zinc ion-promoted adsorption of lysozyme to Cibacron Blue F3GA-attached microporous polyamide hollow-fiber membranes(Elsevier Science Bv, 2001) Şenel, S.; Say, R.; Arıca, Y.; Denizli, A.Dye-affinity and metal chelate affinity adsorption are increasingly used for protein separation. Synthetic hollow fiber membranes have advantages as support matrices in comparison to conventional bead supports because they are not compressible and they eliminate internal diffusion limitations. The goal of this study was to explore in detail the performance of hollow fibers composed of modified polyamide to which Cibacron Blue F3GA and Zn(II) were attached for adsorption of lysozyme. The polymer matrix was characterized by scanning electron microscopy. These dye-affinity and Zn(II) chelated hollow-fibers were used in the lysozyme adsorption-elution studies. The effects of initial concentration of lysozyme and medium pH on the adsorption efficiency of dye-attached and metal-chelated hollow-fibers were studied in a batch reactor. The effect of Zn(II) loading on lysozyme adsorption was also studied. The non-specific adsorption of lysozyme on the polyamide hollow-fibers was 1.8 mg g(-1). Cibacron Blue F3GA attachment significantly increased the lysozyme adsorption up to 63.2 mg g(-1). Lysozyme adsorption capacity of the Zn(II) chelated hollow-fibers (144.2 mg g(-1)) was greater than that of the Cibacron Blue F3GA-attached hollow-fibers. A significant amount of the adsorbed lysozyme (up to 97%) was eluted in 1 h in the elution medium containing 1.0 M NaSCN at pn 8.0 and 25 mM EDTA at pH 4.9. In order to examine the effects of separation conditions on possible conformational changes of lysozyme structure, fluorescence spectrophotometry was employed. We conclude that dye- and metal-chelate affinity chromatography with polyamide hollow-fibers can be applied for lysozyme adsorption without causing any significant conformational changes and denaturation. Repeated adsorption/elution processes showed that these novel dye-attached and Zn(II) chelated hollow-fibers are suitable for lysozyme adsorption. (C) 2001 Elsevier Science B.V. All rights reserved.
