Studies on the Immobilization of Lipase with Embedding and Crosslinking Methods

Purpose Lipase can prepare biodiesel through catalyzing the transesterificationreactions of vegetable oils. The technology of lipase immobilization can greatly improve the efficiency of the use of lipase and reduce the cost of production.Method Using sodium alginate as the carrier, lipase was immobilized by the embedding-crosslinking method, and the immobilization conditions were optimized by orthogonal experiments on the base of single factor experiments.Result The best immobilization conditions were as follows:sodium alginate 2.5%, enzyme addition 400 U/mL, CaCl₂ 5%, and immobilization time 20 min, ethylene glycol diglycidyl ether 0.35%, crosslinking temperature 25 ℃and crosslinking time 1 h. Under above optimized conditions, the activity of immobilized lipase was about 84.90 U/g.Conclusion The optimal pH of immobilized lipase was 8.5, increased 0.5 U than the free enzyme, and the optimal temperature was 40 ℃, was the same with the free lipase. The thermal stability and operating stability of immobilized lipase were significantly enhanced.