Partitioning of protease in PEG/sodium citrate and potassium citrate aqueous two-phase system

Purification of the desired protein from the fermentation broth containing a wide variety of biomolecules is one of the major challenges in the biotechnology industry. The aim of this work was partitioning of protease from the fermentation broth using aqueous two-phase systems (ATPS). ATPS has proved to be a valuable tool for separating and purifying mixtures of biomolecules. In this study, the various aqueous two-phase systems containing polyethylene glycol (PEG 2000 and 8000) at a concentration of 40, 50, and 60% (w/w) with salts sodium citrate, potassium citrate at a concentration of 40 and 50% (w/w) were investigated for extraction of protease from fermentation broth. The results showed that the polyethylene glycol 2000/ sodium citrate system was suitable for the extraction of protease from fermentation broth of Bacillus licheniformis and the best operating system was contained the 40% (w/w) polyethylene glycol 2000, 40%(w/w) sodium citrate resulted in enzyme activity recovery of 48.9% and purification factor of 12.7.