Studies On Bacterium GX-0014 Immobilized Lipase And Synthesizing Sucrose Esteer

Sucrose esters are well known as biosurfactants, which are applied in food industry , pharmaceutics , chemical engineering widely. Their excellent biodegradability as well as the advantages of that they are nontoxic, odorness, not-irritating. At the present time, product of the sucrose ester on market remained mainly in the realms of chemical processing. Chemical methods are mainly performed at high pressure, rigoring of conditions, coloring of products, low selectivity and lots of by-products. However, the enzyme synthesize conquers these disadvantages, the reaction conditions are geniality, the production can be easily purified, the color is shallow, so it possesses important meaning of theory and the value of applications.The study aims to find out a practical enzymatic way to produce sucrose ester, A strain of microorganism screened and isolated from soil named Bacillus subtilis GX-0014, was found to be capable of producing enzyme which can convert sucrose and fatty acid into sucrose fatty acid ester. Further investigations indicated the enzyme produced by Bacillus subtilis GX-0014 was an tracellular enzyme.After centrifugating and condensing the fermentative solution of Bacillus subtilis GX-0014,the crude enzyme solution gained. The immobilized enzyme was prepared by deposition on celite after determining the activity of enzyme. In the reaction system, every 8 mmol lauric acid and 1 mmol sucrose adding 400 mg immobilized lipase(2000U), flask shaken at 30 C reacts 36h ,about 51% of sucrose was esterificated based on the triester of sucrose laurate. Determining thepurified sample by TLC, IR, it was proved that the product by enzyme synthesis was sucrose laurate. At the same time, the synthesis ability of the enzyme catalyzing sucrose and other fatty acid(for example: Stearic Acid , Oleic Acid) was studied.Study on the principium of catalysis characteristic of the immobilizated lipase showed: the optimum pH and temperature were 7.0 and 30 C respectively. After 36h,the reaction on reached equation on the whole.By using the enzyme, sucrose ester was readily formed from commercially available sucrose and fatty acid which showed a great potential in industrial application.