Institut für Funktionelle Grenzflächen (IFG)

Protein separation with magnetic adsorbents in micellar aqueous two-phase systems

  • Autor:

    Becker, J. / Thomas, O. / Franzreb, M. (2009)

  • Quelle:

    Separation and Purification Technology, 65 (2009), 1, 46–53

  • Datum: 2009
  • Becker, J. / Thomas, O. / Franzreb, M. (2009):  „Protein separation with magnetic adsorbents in micellar aqueous two-phase systems“. In:  Separation and Purification Technology, 65 (2009), 1, 46–53

Abstract

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We introduce a new concept for the purification and concentration of macromolecules such as proteins based on the use of magnetic adsorbents in concert with micellar aqueous two-phase systems. Aqueous solutions of certain nonionic surfactants can, depending on the prevailing temperature, separate into two co-existing phases, one enriched, the other depleted in surfactant. These are known as micellar aqueous two-phase systems.

Hydrophilic proteins are normally excluded from the ‘surfactant-rich’ phase of micellar aqueous two-phase systems. We show here that by introducing magnetic microadsorbents into micellar aqueous two-phases the phase selectivity of a hydrophilic protein can be effectively inverted. The magnetic adsorbents adsorb the target protein and pull it out of the ‘surfactant-depleted’ phase into the ‘surfactant-rich’ phase fromwhich it is normally excluded.

Starting froma model solution containing a 1:1 ratio of the hen egg white proteins lysozyme and ovalbumin, the application of magnetic cation exchange micro-adsorbents combined with the nonionic surfactant Triton X-114 resulted in a target lysozyme yield of 74% and purity of >80%. The combination of selective magnetic adsorbents with micellar aqueous twophase systems yields a highly tunable extraction system. Potentially, these so-called ‘Magnetic Extraction Phases’ provide the basis for flexible and easily scaled fractionation processes for hydrophilic proteins.