Lipase-Catalyzed Synthesis Of Sucrose Esters In Organic Solvent/Water Two-Phase System

In this thesis,lipase-catalyzed synthesis of sucrose esters in the organic solvent/water two-phase system was studied in order to find a new synthesis of sucrose esterase system,reveal the basic characteristics and rules of the new reaction in the new system and accumulate data for the further study.Comparing different acyl donor and different types of enzymes in the buffer single-phase system with thin-layer chromatography analysis by the amount of sucrose monoesters obtained,vinyl acetate and microbial alkaline lipase catalytic was the best respectively.In the two-phase system,different organic solvent phase was comparing as above,and tert-amyl alcohol was best.The home-made standard samples were used to determine the conditions of the evaporative light HPLC analysis.Mobile phase:95% water and 5%methanol,flow rate:0.5ml/min,column temperature:40℃, injection volume:10ul,temperature of ELSD drift tube:60℃,with a flow rate of nitrogen:2L/min.Using the HPLC to study the different volume ratio of the two phase (the volume ratio of water phase in two-phase system) on the conversion rate of sucrose.A rule was found out that while the volume ratio of water phase from 0 up to 20%,the sucrose ester begin its formation which following a direct ratio and while it rise up to 90%,the conversion rate of sucrose reached maximum.However,when the reaction system is completely water,the sucrose conversion rate was only 2.1%.Then,the effects of different reaction time,temperature,pH of buffer,amount of enzyme,sugar and the ratio of acy1 donor on the conversion rate of sucrose was studied.It conclued that when the buffer was pH 8.0, temperature was 45℃,enzyme capacity of 0.3g(100U/mmol sugar), and the ratio of sucrose and vinyl acetate was 3mmol:12mmol,response for 24h,sucrose conversion rate was 19.8%.