Resumen
Aqueous two-phase system (ATPS) is an efficient, cost effective, fast, simple and ecofriendly method for the recovery of biomolecules. In the present study, an ATPS composed of polyethylene glycol and ammonium sulphate (NH4)2SO4 was used for the partial purification of proteases from microbial source. The effects of different parameters such as molecular weight of PEG (4000, 6000 and 10000), concentration of PEG (15, 17.5 and 20 %) and concentration of (NH4)2SO4 (7.5, 8.3, 9.1 and 9.9 %) on the partitioning behavior of proteases at room temperature were investigated. Generally, increasing the concentration of PEG and (NH4)2SO4 moved the protease to the top i.e., polymer-rich phase. Increasing the molecular weight of PEG from 4000 to 10000 the partition coefficient decreased subsequently. The highest partition coefficient i.e., 3.32 and maximum activity i.e., 16.06 soxhlet unit was found in an optimum system composed of 20 % PEG 4000 and 9.9 % (NH4)2SO4.