Production, extraction, and thermodynamics protease partitioning from Aspergillus tamarii Kita UCP1279 using PEG/sodium citrate aqueous two-phase systems.

The protease from Aspergillus tamarii Kita UCP1279 extraction by aqueous two-phase PEG-Citrate (ATPS) systems, using a factorial design 24, was investigated. Then, the variables studied were polyethylene glycol (PEG) molar mass (MPEG), concentrations of PEG (CPEG) and citrate (CCIT), and pH. The responses analyzed were the partition coefficient (K), activity yield (Y) and purification factor (PF). The thermodynamic parameters of the ATPS partition were estimated as a function of temperature. ATPS was able to pre-purify the protease (PF = 1.6) and obtained 84% activity yield. The thermodynamic parameters ΔG°m (-10.89 kJ mol-1), ΔHm (-5.0 kJ mol-1) and partition ΔSm (19.74 J mol-1 K-1) showed that the preferential migration of almost all protein contaminants of the crude extract to the salt-rich phase, while the preferred protease was the PEG rich phase. The extracted enzyme presents optimum temperature and pH at range of 40-50 °C and 9.0-11.0, respectively. Moreover, the enzyme was identified as serine protease based on inhibition profile. ATPS showed the satisfactory performance as the first step for Aspergillus tamarii Kita UCP1279 protease pre-purification.