Biodiesel productionbyenzymatictransesterification ofwastecookingoil(WCO)topartiallysubstitute petroleum dieselisconsideredasoneofthemeasuresforsolvingthetwinproblemsofenvironment pollution andenergydemand.Highcostoflipasesisconsideredasamainbarriertocommercializethe enzymatic transesterification. Inthepresentwork,superparamagneticironoxidenanoparticles(SPION) havebeensynthesized,coveredbySilicaandthengraftedbyaldehydegroupsinordertoimmobilize B. cepacia lipase, asapromisingmethodenhancingtheeconomicviabilityofenzymatictransesterification. The resultsdemonstratedthattheaveragesizeofSPIONshasbeendeterminedtobearound20nm.The nanoparticles linkedtothelipaseshavedisplayednearlysuperparamagneticproperty.Effectivevariables on theenzymatictransesterification havebeenevaluatedandtheconversionofWCOtobiodiesel reached 91%inmethanol:oilmolarratioof6:1,immobilizedlipaseconcentrationof25wt%, n-hexane content of10wt%,watercontentof10wt%,reactiontemperatureof35 °C, andreactiontimeof35h. Immobilized lipasecouldberecoveredeasily,usedrepeatedly,andthedecreaseinitsactivitywasnot largelyobserved.
