Study Of Novel Immobilized Lipase And ITS Catalysis In Preparing Biodiesel

Biodiesel is a fuel consisted of the fatty esters from vegetable oils or animal fats (mainly composed of triglycerides) transesterification with alcohols, which is a renewable and environment-friendly bio-energy. Production of biodiesel can be catalyzed by lipase obtained more widely attention compared with traditional chemical systhesis which is high energy consumption, contaminate the environment, high production costs. It has the advantage which is mild condition, non-pollution, product easy to separate. Lipase is a carboxyl ester hydrolase, its natural substrate is glycerides. It is an important industrial enzyme, used widely. However, free lipase exist many drawbacks, such as expensive, difficult to separate from the reaction and difficult to achieve industrialization continuous reaction. Therefore, the application of immobilization technology could reduce the produce of these drawbacks, the combined use of adsorption and embedding to immobilized laboratory-made Candida sp.99-125 lipase, and the immobilized lipase was used to catalyze synthesis of biodiesel.Diatomaceous earth as a carrier for the adsorption of lipase was studied, and the optimal conditions for preparation were received: phosphate buffer solution pH 7.5, the mass ratio of lipase and diatomite (adding additives:polyethylene glycol 6000, magnesium sulfate, Tween 80, coconut oil, lecithin) is 1:3, the adsorption temperature is 25℃, adsorption time is 3h, and embedding performed after the adsorption process.1.5% alginate solution 15ml and 1% gelatin solution 15ml was added mixing uniformity, with a syringe dropwise added to 0.4mol/L calcium chloride solution to form a gel-like pellets, drying preservation.The resulting immobilized lipase was used for catalyzing the esterification reaction of lauric acid and n-octanol. After immobilized lipase continuous utilized for 28 times, the activity was remained stability. The activity was reduced little when the immobilized lipase was storage at 4℃ for five months; immobilization improved the storage stability of lipase.By scanning electron microscopy analysis of the internal structure of immobilized enzyme. Immobilized enzyme inside aperture is multipurpose and uniform particle size, the network structure is developed. By energy spectrum analyzing the immobilized internal enzyme and diatomite exist as adsorption, and distributed.The immobilized lipase was used to catalyze transesterification reaciotn of waste oil to produce biodiesel, the highest conversion up to 92% in a single batch reaction, after being recycled 11 times the conversion maintained above 70%,。After immobilized,the activity and stability of the lipase enzyme are improved, and convenient for industrial production.