摘要
对粘质沙雷氏菌脂肪酶进行了固定化研究,确定硅藻土和环氧树脂EupergitC是较好的固定化载体.固定化后酶的热稳定性、pH稳定性及储存稳定性均明显提高.以EupergitC共价固定的脂肪酶,其操作稳定性比硅藻土吸附酶好,重复使用10批次后,剩余酶活力还有50%左右,戊二醛交联对EupergitC固定化酶稳定性的提高没有明显效果,而硅藻土吸附酶经戊二醛交联后稳定性有所提高,经5批次反应后剩余酶活力还有50%.使用交联后的硅藻土固定化酶(1g,200U),在两相搅拌反应器(工作体积200ml,甲苯∶水体积比=1)中对地尔硫卓手性前体(±)-反式3-(4’-甲氧苯基)缩水甘油酸甲酯((±)-MPGM)(有机相浓度为0.5mol/L)进行了催化拆分,经5批次反应后,共得纯(2R,3S)-(-)-MPGM18.6g,产品光学纯度(对映体过量)>99%,总收率为37.2%.
Seven carriers were investigated for immobilization of the lipase from Serratia marcescens ECU1010, and diatomite and Eupergit C were found to be ideal supports. The thermal and storage stability of the lipase was significantly improved after being immobilized onto these two supports. After heating at 50 ℃ for 6 h, only a small decrease in the activity was observed for the diatomite-adsorbed lipase. About 50 % of the initial activity was retained when the two immobilized enzyme samples were storaged at 4 ℃ for 180 days. Operational stability tests indicated that the half-life of the lipase immobilized on Eupergit C was about 2-fold longer than that of the diatomite-immobilized lipase. The crosslinking with glutaraldehyde had no significant effect on the activity of the Eupergit C-immobilized lipase, whereas the reusability of the crosslinked diatomite-immobilized enzyme was slightly improved. Using the crosslinked diatomite-immobilized lipase, an up-scaled bioresolution of （ ± ）-3-（4＇ methoxyphenyl）glycidic acid methyl ester （（ ± ）-MPGM） was performed in a 500-ml emulsion reactor with 200 ml biphasic solution （toluene：water = 1：1） at 30 ℃ and 0.5 mol/L of （ ± ）-MPGM in toluene. After 5 batches of reaction, crystalline （2R, 3S）-（-）-MPGM with a chemical purity of 100 % and optical purity of 〉 99% enantiomeric excess was obtained in a yield of 37.2 %.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第2期175-179,共5页
基金
国家自然科学基金(20506037
203900506)
上海市重大科技攻关项目(05DZ19350).
