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Immobilization of Phospholipase A1 and its Application in Soybean Oil Degumming

Yu, Dianyu, Jiang, Lianzhou, Li, Zhenlan, Shi, John, Xue, Jun, Kakuda, Yukio
journal of the American Oil Chemists' Society 2012 v.89 no.4 pp. 649-656
calcium, calcium alginate, crosslinking, degumming, glutaraldehyde, hydrolysis, immobilized enzymes, pH, phospholipase A1, phospholipids, phosphorus, soybean oil, temperature, thermal stability, vegetable oil
Phospholipase A1 (PLA1), or Lecitase® Ultra, was immobilized on three different supports, calcium alginate (CA), calcium alginate-chitosan (CAC), and calcium alginate-gelatin (CAG), and crosslinked with glutaraldehyde. The results indicated that PLA1–CA retained 56.2% of the enzyme’s initial activity, whereas PLA1–CAC and PLA1–CAG retained 65.5 and 60.2%, respectively. Compared with free PLA1, the optimal pH of immobilized PLA1 shifted to the basic side by 0.5–1.0 pH units and the pH/activity profile range was considerably broadened. Similarly, the temperature-optima of PLA1–CAC and PLA1–CAG increased from 50 to 60 °C, and their thermal stability increased with relative activities of more than 90% that covered a wider temperature range spanning 50–65 °C. In a batch oil degumming process, the final residual phosphorus content was reduced to less than 10 mg/kg with free PLA1, PLA1–CAC and PLA1–CA in less than 5, 6 and 8 h respectively while PLA1–CAG was only able to reduce it to 15 mg/kg in 10 h. When the PLA1–CAC was applied in a plant degumming trial, the final residual phosphorus content was reduced to 9.7 mg/kg with 99.1% recovery of soybean oil. The recoveries of immobilized PLA1–CAC and activity of PLA1 were 80.2 and 78.2% respectively. Therefore, it was concluded that PLA1–CAC was the best immobilized enzyme complex for the continuous hydrolysis of phospholipids in crude vegetable oils.