earticle

영어

Since methanol is a typical acyl acceptor for the transesterification reaction of biodiesel production, it was applied to the enzymatic conversion process using lipase. However, its inhibition on the lipase activity was reported, leading to extended reaction time and higher enzyme cost. To overcome such difficulties, stepwise addition of methanol during alcoholysis reaction using lipase was proposed. In this work, the lipase catalyzed conversion of soybean oil into biodiesel using 4% of the immobilized lipase based on the weight of oil was carried out by stepwise addition of methanol to reduce methanol inhibition on lipase. In comparison with our previous result, 90% conversion yield at 15 hours by using a two-steps addition of methanol every four hours, the reaction time to obtain 90% conversion yield was shortened to 11 hours by adjusting the two-steps feeding time of methanol into 2 and 4 hours and increasing the reaction temperature. In order to observe the effects of methanol concentration on lipase activity, the methanol concentration and the residual lipase activity after 24 hours were measured. Because of lower methanol concentration in the stepwise reaction, the residual lipase activity exploiting two-steps feeding strategy was about 9 times higher than the batch reaction.