Immobilized Lipase Candida Sp.99-125 And Its Application In Biodiesel

Biodiesel is a kind of renewable and environmentally friendly biofuels. It is fatty acid ester which synthetics by plant or animal fats (mainly composed of triglycerides) and alcohol. With the intensification of the energy crisis, biodiesel has been taken more and more attention. Enzyme catalyst biodiesel reaction has been widely researched, it exhibit a number of advantage, mild condition, easy operation and no pollution. However, there exist several problems restrict the practical use such as, high cost, instability and recovery. This study aims to improve the application of lipase, the immobilized method combined adsorption and crosslink was used to immobilize lipase Candida sp. 99-125, and used it in synthesis of biodiesel.The factors in the adsorption process has been optimized and the best conditions of immobilized has been obtained. The optimal conditions in adsorption process is:5 mL 50 mM pH 8.0 phosphate buffer solution containing 0.25 g lipase was mixed with 0.25 g D311 resin, immobilized at 35 ? for 4 h. Crosslinking process is followed the adsorption. After adsorption, the same volume solution which dissolved crosslinking agent glutaraldehyde and Genipin was added. Cross-linking conditions were optimized. The optimal conditions are:the optimal concentration of glutaraldehyde and Genipin are 0.1% (w/v) and 0.25% (w/v), crosslinking time for 2 h and 4 h, crosslinking temperature is 20 ? and 30 ?.The enzymology performance of the immobilized enzyme has been investigated. The thermal stability is obviously improved and it shows good storage stability. In order to evaluate the stability of immobilized lipase in repeated use, batch esterification of lauric acid and 1-octanol was conducted by the addition of immobilized lipase. It remained stable after continuous reaction of 40 batches.The characterization of resins and enzymes was investigated by several methods. The resin is nearly circle and the developed hole was separated in the cross section. The diameter of the hole is larger than 100 nm, which allow the substrate through. The resin surface and the cross section are rich in amino. In addition, it can be confirmed that the lipase is successfully immobilized on the resin and the distributes in the resin surface and internal channel were uniformed.The synthesis process of biodiesel was optimized. The immobilized lipase was used to produce biodiesel with the transesterification of waste oil. The highest biodiesel conversion rate was obtained above 93%, the enzyme activity was maintained over 70% after consecutive 13 batch reaction.