毕赤酵母表面展示脂肪酶催化合成肉豆蔻酸糖酯

Synthesis of myristic acid sugar ester catalyzed by Candida antarctica lipase B displaying Pichia pastoris

研究了毕赤酵母表面展示脂肪酶（CALB）全细胞催化剂的较佳活性条件，结果显示，适宜的反应温度为50-60℃。以CALB为催化剂，比较了不同底物对糖酯合成的影响。以1，2-O-异亚丙基-D-呋喃葡萄糖（IpGlc）为酰基受体，肉豆蔻酸为酰基供体，考察了有机溶剂种类、CALB的添加量、底物摩尔比、分子筛的添加量、初始水活度对合成6-O-肉豆蔻基-1，2-O-异亚丙基-α—D一呋喃型葡萄糖酯（IpGlc—C14）的影响，得到较佳的合成条件为：丙酮5mL、CALB（干粉）0．3g,n（IpGlc）：n（肉豆蔻酸）=1：3（其中IpGlc0．5mm01）、4A分子筛0g、初始水活度aw=0．11、反应温度50℃、200r／min反应72h。在此条件下，IpGlc—C14的收率为91．25％。比较了CALB和固定化脂肪酶Novozym435对IpGlc—C14合成的反应进程的影响，结果显示使用Novozym435的反应速率快，而CALB的最终收率较高。

The enzyme activity of Candida antarctica lipase B （CALB） displaying Pichia pastoris was investigated. Results showed that the enzyme displays the highest activity at 50 - 60 %. Effect of separate substrates catalyzing by CALB was compared. In a case using 1,2 - O - isopropylidene - α - D - glucofuranose （IpGlc） as the acyl receptor and myristic acid as the acyl donor, the effect of the polarity of organic solvent, the dosage of catalyst, the molar ratio of the substrates, the dosage of 4A molecular sieve, and initial water activity was studied. The suitable reaction conditions are as follows：acetone,5 mL;CALB （dry powder） ,0. 3 g; n（IpGlc） ： n（ myristic acid） = 1 ： 3 （ with IpGlc 0. 5 mmol） ; no 4A molecular sieve to be used ; water activity, aw = 0. 11 ; reaction temperature, 50 ℃; agitator speed, 200 r/min for 72 h. The final yield achieves 91.25 %. IpGlc - C14 reaction results of using CALB and Novozym 435 were compared and showed that Novozym 435 displays higher reaction rate, and CALB displays higher final yield.