Application of Aqueous Two-phase Systems in the Extraction of Bovine Serum Albumin

Protein partitioning in an aqueous two-phase system (ATPS) has been found to be a powerful method for extracting and separating mixtures of biomolecules. In ATPS, many factors influence the partition coefficient K (which is the ratio of protein concentration in the top phase to that in the bottom phase) and the recovery percent (Rec%). Two systems of ATPS were used: first, polyethylene glycol (PEG4000)/sodium phosphate, and second, PEG4000/dextran. The behavior of Rec% and K of pure bovine serum albumin in ATPS has been investigated throughout the study of the effects of five parameters: temperature T), the concentration of polyethylene glycol (PEG4000), the concentration of sodium phosphate or dextran, pH, and the addition of sodium chloride as a supporting agent. In both systems, pH was the more significant parameter affecting Rec% and partition coefficient K. In the first system, the maximum Rec% and K were 98.08% and 50.99, respectively, at a temperature of 31 degrees C, the concentration of PEG4000 of 1.5 g/10 mL, the concentration of sodium phosphate at 2.4 g/10 mL, pH 10, and the concentration of NaCl at 0.5 M. While in the second system, the parameter that has a more significant effect on Rec% and K was the temperature. The maximum Rec% and K were 97.54% and 39.7, respectively, at a temperature of 31 degrees C, with a concentration of PEG4000 1.5 g/10 mL, the concentration of dextran 2.4 g/10 mL, pH 5, and concentration of NaCl at 0.1 M.