title: Interfacial partitioning behaviour of bovine serum albumin in polymer-salt aqueous two-phase system.
abstract: A relationship is proposed for the interfacial partitioning of protein in poly(ethylene glycol) (PEG)-phosphate aqueous two-phase system (ATPS). The relationship relates the natural logarithm of interfacial partition coefficient, ln G to the PEG concentration difference between the top and bottom phases, Δ[PEG], with the equation ln G=AΔ[PEG]+B. Results showed that this relationship provides good fits to the partition of bovine serum albumin (BSA) in ATPS which is comprised of phosphate and PEG of four different molecular weight 1450g/mol, 2000g/mol, 3350g/mol and 4000g/mol, with the tie-line length (TLL) in the range of 44-60% (w/w) at pH 7.0. The decrease of A values with the increase of PEG molecular weight indicates that the correlation between ln G and Δ[PEG] decreases with the increase in PEG molecular weight and the presence of protein-polymer hydrophobic interaction. When temperature was increased, a non-linear relationship of ln G inversely proportional to temperature was observed. The amount of proteins adsorbed at the interface increased proportionally with the amount of BSA loaded whereas the partition coefficient, K remained relatively constant. The relationship proposed could be applied to elucidate interfacial partitioning behaviour of other biomolecules in polymer-salt ATPS.
authors.affiliation: Department of Process and Food Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Yin Hui
authors.initials: YH
authors.lastname: Chow
authors.forename: Yee Jiun
authors.initials: YJ
authors.lastname: Yap
authors.forename: Mohd Shamsul
authors.initials: MS
authors.lastname: Anuar
authors.forename: Bimo Ario
authors.initials: BA
authors.lastname: Tejo
authors.forename: Arbakariya
authors.initials: A
authors.lastname: Ariff
authors.forename: Pau Loke
authors.initials: PL
authors.lastname: Show
authors.forename: Eng-Poh
authors.initials: EP
authors.lastname: Ng
authors.forename: Tau Chuan
authors.initials: TC
authors.lastname: Ling
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008962:Models, Theoretical; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012492:Salts; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000295:instrumentation*; D013696:Temperature
chemical_list: D011108:Polymers; D012492:Salts; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols
keywords: Aqueous two-phase system; Bioseparation; Interfacial partition; Protein recovery; Purification; Statistical mechanics