Partition and recovery of phytase from Absidia blakesleeana URM5604 using PEG–citrate aqueous two-phase systems

The partition and recovery behavior of phytase, produced by solid-state cultivation utilizing citrus pulp as substrate, was determined in an aqueous two-phase system (ATPS), composed by polyethylene glycol (PEG–citrate). The 24 factorial design was conducted to evaluate the effect of the following independent variables: PEG molar mass, PEG and citrate concentrations and pH, while partition coefficient, recovery and purification factor were selected as the variables responses. The best recovery in phytase activity (115.24%) condition was obtained with 26% (w/w) PEG 8000 (g/mol), 12% (w/w) sodium citrate at pH 8.0, showing a purification factor of 1.35. However, the highest partition coefficient (14.42) was observed within a 26% (w/w) PEG 400 (g/mol) and a 20% (w/w) sodium citrate at pH 6.0. The independent variables which more influenced on the partition coefficient and recovery were citrate concentration and PEG mass molar, respectively. The results suggest that PEG–citrate ATPS is an interesting and efficient alternative to partition and recovery of phytase from fermentation broth produced by Absidia blakesleeana URM5604.