Pretreatment of immobilized Candida antarctica lipase for biodiesel production from waste oil

The transesterification of waste oil to biodiesel catalyzed by pretreated immobilized Ca-ndida antarctica lipase was investigated.Transesterification progressed much faster when the enzyme was pre-incubated in tert-butanol for 3 h and subsequently in waste oil for 4 h.The inhibition of superfluous methanol still existed after the pretreatment of immobilized Candida antarctica lipase.The methyl ester content reached 97.86% within 4 h by stepwise addition of equivalent methanol at 0.5 h intervals from 0 to 2.5 h with the molar ratio of total methanol to oil 3:1.The efficiency of transesterification was 6 times faster than that of unpretreated immobilized lipase.The enzyme sho-wed no appreciable loss after being continuously operated.