Lipozyme TL 100L的固定化及其催化合成蔗糖-6-乙酯

采用树脂吸附法固定脂肪酶Lipozyme TL 100 L，并用于催化合成蔗糖-6-乙酯（S-6-a）。比较7种树脂对Lipozyme TL 100 L的吸附与固定化酶合成S-6-a能力，选择非极性大孔树脂HZ-802为固定化载体。固定化酶在吸附温度30 ℃，蛋白吸附量50.47～58.1 mg/g树脂，相对水含量小于5%时，S-6-a产率达80%以上。用异丙醇以体积比0.5∶1处理Lipozyme TL 100 L，固定化酶的S-6-a产率可达95.4%。固定化酶反复使用8次，S-6-a产率仍有34.2%。与商品固定化酶Lipozyme TLIM相比，HZ-802吸附法制备的固定化酶催化转酯反应的活化能降低了6.47 kJ/mol。

Immobilization of Lipozyme TL 100 L and catalytic synthesis of sucrose-6-acetate

Immobilization of Lipozyme TL 100 L on resin was realized by adsorption，and its application in sucrose-6-acetate（S-6-a）synthesis was then investigated. The results showed that nonpolar macroporous resin of HZ-802 was the best carrier among 7 kinds of resins by comparing both protein adsorptivity and transesterification capacity. The S-6-a yield was attained more than 80% in the condition of immobilization temperature 30 ℃，adsorption capacity between 50.47～58.1 mg/g resin，and immobilized enzyme relative water content under 5%. Disposing Lipozyme TL 100 L with 2-propanol at the volume ratio of 0.5∶1，the S-6-a yield of the immobilized enzyme reached 95.4%. And the yield still remained 34.2% when the immobilized enzyme was repeated 8 times. The transesterification followed Ping-Pong Bi Bi mechanism by the studies of apparent michaelis constant K_m′ at different substrate concentrations. Activation energy of the immobilized enzyme by adsorption on HZ-802 was reduced 6.47 kJ/mol compared with the commercial Lipozyme TLIM.