Aqueous two-phase poly (ethylene glycol)-sodium polyacrylate system for amyloglucosidase purification: equilibrium diagrams and partitioning studies

Abstract

Extraction and purification of amyloglucosidase (AMG) using aqueous two phase systems (ATPSs) composed by polyethylene glycol (PEG, average molar mass of 4000 g/mol) and sodium polyacrylate (NaPA, average molar mass of 15,000 g/mol) has been studied. Phase equilibrium diagrams were obtained at pH 6.0 and 9.0, which were used for partitioning studies. The selectivity (S) and partition coefficient (Ke) of AMG were evaluated as a function of pH, temperature and concentration of PEG and NaPA, and it was found that these parameters were affected by pH and NaPA concentrations. A face-centered design with the response surface methodology was applied for selectivity optimization. The highest value found for S was 1.6 at pH of 6.5, temperature of 25 °C, PEG concentration of 12.5% (w/w) and NaPA concentration of 11.4% (w/w). The corresponding Ke was 2.0. The purification factor (PF) and the recovery yield (Y) were determined as 1.9% and 86%, respectively.