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Titolo:
Role of electrophoretic mobility of protein on its retention by an ultrafiltration membrane - Comparison to chromatography mechanisms
Autore:
Chaufer, B; Rabiller-Baudry, M;
Indirizzi:
Univ Rennes 1, INRA, Lab Proc Separat, UC 991, F-35042 Rennes, France UnivRennes 1 Rennes France F-35042 arat, UC 991, F-35042 Rennes, France
Titolo Testata:
JOURNAL OF CHROMATOGRAPHY B
fascicolo: 1, volume: 753, anno: 2001,
pagine: 3 - 16
SICI:
1387-2273(20010325)753:1<3:ROEMOP>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
SIZE-EXCLUSION CHROMATOGRAPHY; IONIC-STRENGTH; PHYSICOCHEMICAL ENVIRONMENT; NANOFILTRATION MEMBRANES; EXCHANGE CHROMATOGRAPHY; MODEL; SEPARATION; FILTRATION; POLYMERS; LYSOZYME;
Keywords:
electrophoretic mobility; ultrafiltration membrane; proteins;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Chaufer, B Univ Rennes 1, INRA, Lab Proc Separat, UC 991, Campus Beaulieu Bat 10 A,263 Ave Gen Leclerc, F-35042 Rennes, France Univ Rennes 1 Campus Beaulieu Bat 10 A,263 Ave Gen Leclerc Rennes France F-35042
Citazione:
B. Chaufer e M. Rabiller-Baudry, "Role of electrophoretic mobility of protein on its retention by an ultrafiltration membrane - Comparison to chromatography mechanisms", J CHROMAT B, 753(1), 2001, pp. 3-16

Abstract

Lysozyme and lactoferrin, two globular proteins, were first studied separately in order to elaborate a strategy for the improvement of their separation by ultrafiltration (UF) with zirconia-based membranes of different charge sign and pore radius. The electrophoretic mobility (mu) at fixed pH and variable ionic strength was used for the characterisation of both proteins and zirconia particles, similar to the active layer of the membrane during the UF run. Specific adsorption of phosphate ions was shown for both proteins resulting in new isoelectric points. The occurrence of electrostatic exclusion mechanism in addition to the molecular sieving in UF of charged solutes was shown for:Low molecular weight solute: multivalent citrate at pH 6 was specifically adsorbed on zirconia and its transmission through the membrane (defined as the ratio of the concentration in the permeate to that of the feed solution) was reduced in the range 0.001-0.01 mol l(-1) of citrate concentrationProteins: their transmissions increase when the ionic strength increases (ion-exchange is not the relevant mechanism because transmission is irrespective of the initial charge of the membrane compared with the protein charge). A model based on convection, diffusion and electrophoretic migration mechanisms (CDE model) was proposed to take into account this behaviour. The CDEmodel predicts the possible existence of a depleted sub-layer of the charged protein in the concentration polarisation layer, located in the close vicinity of the membrane surface. A strategy for the separation of two proteins in mixed solution was proposed by varying both the physico-chemical environment in the feed solution (pH, ionic strength, chemical nature of the electrolyte) and the membrane pore radius. Maximum selectivity was obtained when the target protein (to be transmitted in the permeate side) is close tobeing uncharged due to specific adsorption of electrolyte ions. Ultrafiltration selectivity is enhanced with membrane of large pore radius, which provides high transmission of the target protein and efficient electrostatic exclusion of the solute to be retained in the retentate side. This UF approach corresponds roughly to the separation of one uncharged and one charged protein from a mixed solution by size exclusion chromatography of the uncharged protein combined with electrostatic exclusion of the charged protein due to packing of similar charge. (C) 2001 Elsevier Science BN. All rights reserved.

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Documento generato il 23/01/21 alle ore 03:06:01