Study Of The Immobilized Lipase By Two Microspheres

Compared with non-biological catalysts, lipase is widely used in many aspects due totheir high efficiency, specificity and mild reaction conditions. However, the poor stability andreusability of free lipase limit its applications in industrial production. In order to overcomethese drawbacks, enzyme is often immobilized via adsorption, entrapment, or covalentbinding.This essay includes two aspects.First, by using styrene (St) and acrylic acid (AA) as monomers in the presence ofmagnetic nanoparticles, poly(St-AA) magnetic microspheres were prepared through emulsionpolymerization and used to immobilize Candida rugosa lipase via covalent binding. Toreduce the effect of steric hindrance on lipase activity, ethylenediamine and poly(ethyleneglycol)(PEG)400/800/4000were employed as spacer arm to modify the microspheres,respectively. The results showed that the steric hindrance could be prevented effectively byusing PEG800/4000as spacer arm. Furthermore, the influence of enzyme loading wasinvestigated and the results indicated that a high enzyme loading would exert an effect onlipase activity by steric hindrance. Moreover, PEG modification degree would also haveeffect on the immobilized lipase activity.Second, poly(VAC-AM) microspheres were synthesized via suspension polymerization.Candida rugosa lipase was covalently immobilized on poly(VAC-AM) microspheres, whichwere activated by using epichlorohydrin (ECH). Through optimizing the reaction conditionsof microspheres modified with epoxy group and immobilization lipase, the influences ofseveral parameters such as speed of agitation, the amount of ECH, immobilization time andthe amount of lipase were investigated. The results showed that the optimum reactionconditions were600r/min,3mL ECH,5mg lipases and the immobilization time was2h.The maximum activity recovery of immobilization lipase was48%.