Chemically modified magnetic immobilized phospholipase A1 and its application for soybean oil degumming

In this paper, the free Phospholipase A(1) (PLA(1)) was immobilized on a magnetic carrier. The average particle diameter of the magnetic carrier was 97 +/- 1.3 nm, and the average particle diameter of the magnetically immobilized PLA(1) was 105 nm +/- 1.3 nm. The enzyme activity was 1940.5 U/g. The magnetic enzyme was chemically modified with formaldehyde, dextran-aldehyde, and dextran-aldehyde-glycine. The proportions of primary amino groups in the modified magnetic immobilized enzyme PLA(1) were 0, 53.5% and 47.3%, respectively. The optimum pH of the enzyme after chemical modification was 6.5. When the system temperature was 60 degrees C, the magnetically immobilized PLA(1) modified with dextran-aldehyde-glycine had the optimal activity and stability. This chemically modified magnetic immobilized PLA(1) was applied to soybean oil degumming at 60 degrees C, 6.5 h (reaction time), and 0.10 mg/kg (enzyme dosage). The phosphorus content in the degummed oil was 9.2 mg/kg. The relative enzyme activity was 77.6% after 7 reuses which would be potentially advantageous for industrial applications.