Partitioning and extraction protease from Aspergillus tamarii URM4634 using PEG-citrate aqueous two-phase systems

PEG-citrate Aqueous Two-Phase Systems (ATPS) were used to recover and partially purify protease from Aspergillus tamarii URM4634 produced by Solid State Fermentation. Experiments were performed according to a 24-full factorial design using PEG molar mass (MPEG), PEG concentration (CPEG), citrate concentration (CCIT) and pH as independent variables; and purification factor (PF), partition coefficient (K) and activity yield (Y) as responses. Protease showed high activity in the PEG-rich phase, also MPEG and CCIT were shown to exert positive effects on all responses. The highest purification factor (3.95) was obtained using MPEG=8000 g/mol, 24% (w/w) CPEG, 20% (w/w) CCIT at pH 8.0. Consequently, the selected ATPS proved to be efficient and can be used as a first step for pre-purification of protease from solid state fermented of A. tamarii URM4634.