title: One-step separation of β-galactosidase from β-lactoglobulin using water-in-oil microemulsions.
abstract: Solubilisation of β-galactosidase from Kluyveromyces lactis in Aerosol-OT water-in-isooctane microemulsions was measured as a function of buffer type and concentration, pH, and protein concentration. For buffer concentrations above ∼40mM, the enzyme was largely excluded from the droplets. Based on these results, a one-step separation was developed. A protein-containing aqueous feed was injected into an AOT/isooctane solution, with the feed volume slightly in excess of the predicted water solubility. Impurity proteins were entrapped inside the microemulsion droplets that then formed in the organic phase, while the high MW target protein was excluded and entered a newly formed, excess aqueous phase. The separation of β-galactosidase from the test protein β-lactoglobulin was most complete at 100mM KCl salt concentration, where the droplets were large enough to carry β-lactoglobulin but too small for β-galactosidase. At 100mM [KCl], 92% of the total enzyme activity was recovered in a concentrated and virtually pure form.
authors.affiliation: Department of Food Science and Technology, University of California, Davis, CA 95616, United States; Department of Food Engineering, Middle East Technical University, Ankara 06531, Turkey; Department of Food Engineering, Süleyman Demirel University, Isparta 32260, Turkey.
authors.forename: Bekir G
authors.initials: BG
authors.lastname: Mazı
authors.affiliation: Department of Food Engineering, Middle East Technical University, Ankara 06531, Turkey.
authors.forename: Haluk
authors.initials: H
authors.lastname: Hamamcı
authors.affiliation: Department of Food Science and Technology, University of California, Davis, CA 95616, United States; Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, United States. Electronic address: srdungan@ucdavis.edu.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Dungan
mesh_terms: D043322:Lactase; D007782:Lactoglobulins / Q000737:chemistry*; D008823:Micelles; D014867:Water; D001616:beta-Galactosidase / Q000737:chemistry*
chemical_list: D007782:Lactoglobulins; D008823:Micelles; D014867:Water; D043322:Lactase; D001616:beta-Galactosidase
keywords: Bioseparations; Enzymes; Extraction; Lactase; Reversed micelles