Extraction of soybean lipoxygenase by PEG / (NH4) 2SO4 aqueous Two- phase systems

Separation of lipoxygenase directly from nonfat soybean in aqueous two- phase systems ( ATPS) of polyethylene glycol / ammonium sulfate was studied. The effects of polyethylene glycol 2000 ( PEG2000) concentration, ( NH4) 2SO4concentration, Na Cl concentration, and p H value on the extraction of soybean lipoxygenase were investigated in terms of partition coefficients, phase volume of both enzyme activity and recovery.Orthogonal experiment was used to further analyze and optimize the separation of lipoxygenase. The results indicated that the optimum separation conditions of single factor conditions were PEG2000 13%, ( NH4) 2SO415%, Na Cl 1% and p H5.8. Maximum distribution coefficient and yield of lipoxygenase was 9.710 and87.6% under the optimum separation conditions of PEG2000 13%, ( NH4) 2SO417% and p H5.2 obtained by orthogonal experiment.