Immobilization of lipase on macroporous resin by adsorption-crosslinking method

Objective  To provide a basis for immobilization of industrial enzymes such as lipase using macroporous resin for adsorption and epoxy crosslinker for crosslinking.

Method  The immobilization of lipase was performed through adsorption using macroporous resin as the carrier and epoxy crosslinker as the crosslinking agent. We investigated the effects of different factors on adsorption-crosslinking immobilization, and used response surface design to optimize the immobilization conditions. The immobilized enzyme was prepared and its stability was investigated.

Result  Macroporous resin HPD750 was selected as the carrier, and poly (ethylene glycol) diglycidyl ether was selected as the crosslinker. The optimal conditions of lipase immobilization were as follows: Adsorption temperature 45 ℃, enzyme addition amount 60 mg·g^–1, crosslinking temperature 30 ℃, crosslinking time 12.5 h, pH6.36, and comcentration of crosslinking agent 0.7%. Under these optimized conditions, the immobilized lipase activity was 565.31 U·g^–1 and the recycled rate of lipase activity was 32.16%. Compared with free lipase, the immobilized lipase exhibited obviously better thermal stability and pH stability. The immobilized lipase was of good operation stability and remained 34.86% of the original activity after repeated usage for 10 times. The immobilized lipase also exhibited good storage stability and remained 64.81% of the original activity after storage at 4 ℃ for 30 days.

Conclusion  Using macroporous resin HPD750 as the carrier and poly (ethylene glycol) diglycidyl ether as the crosslinker, the immobilized enzyme has significantly improved thermal stability and pH stability, and it also exhibits good operation stability and storage stability.