大孔树脂修饰固定化脂肪酶催化合成L-薄荷醇酯

L-menthol oleate is usually synthesized with menthol and fatty acid, and it is an efficient mint with fresh odor, which has important applications in cosmetics, medicine and food industry. Enzymatic methods are usually the optimal synthetic method. The esterification of L-menthol oleate was studied in solvent-free system using lipase immobilized on macroporous resin as the catalyst, and the optimal reaction conditions for enzymatic synthesis of L-menthol oleate were studied. The best esterification rates were 91% (NKA) and 89.8% (HA) under conditions of 1 mol∙L ^-1 L-menthol, molar ratio of acid to alcohol = 1, enzyme activity = 1 U, temperature = 50℃ and water = 4 μL with reaction time = 24 h. The immobilized lipase with resins modified with dopamine or benzoquinone show esterification rates of 94.6% and 95.8%, respectively. Covalent immobilization is beneficial for lipase stability and esterification, and the esterification rates of the covalent immobilized lipase are over 70% after ten batches, which is 1.75 times higher than that of the adsorbed immobilized lipase. These results show that the modification of resins with dopamine and polyethylene glycol can improve the catalytic performance of immobilized lipase.