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Alternative TitleStudies on epoxidation reaction of oleic acid catalyzed by lipase immobilized by different methods
Thesis Advisor张松平
Degree Grantor中国科学院研究生院
Degree Discipline生物工程
Keyword脂肪酶   微球   纳米纤维   同轴共纺   环氧化
Abstract在H2O2存在的条件下,脂肪酶可以有效催化不饱和脂肪酸上双键的环氧化反应,制备具有广泛用途的环氧植物油和环氧脂肪酸,但反应体系中的H2O2和反应生成的过氧酸导致酶活性损失较大,需通过固定化提高酶的稳定性。本文采用微球和纳米纤维两类载体固定化脂肪酶,以油酸环氧化为模型反应分别构建非水相反应体系和油水两相反应体系,考察固定化脂肪酶催化油酸环氧化反应的活性和重复使用稳定性,并与葡萄糖氧化酶偶联,考察偶联反应体系的活性和操作稳定性,具体如下: (1)考察不同类型游离脂肪酶催化油酸环氧化反应的活力,以南极假丝酵母脂肪酶B(Candida Antarctica Lipase B,CALB)的活力最高,因此选用CALB催化油酸环氧化反应。 (2)分别用8种具有不同孔径、亲疏水性和功能基团的微球吸附或偶联脂肪酶。CALB在介孔聚苯乙烯微球PST30上负载量最高为100.7 mg/g,超大孔聚苯乙烯微球PST固定化CALB的比活力最高,在非水相和油水两相体系中的比活力分别是Novozym 435的1.8倍和7.3倍,且重复使用性能与Novozym 435相当。 (3)在聚氨酯纳米纤维表面固定化CALB,又利用中空聚氨酯纳米纤维包埋CALB,中空纳米纤维包埋酶的比活力更高,在非水相体系和油水两相体系中的比活力分别是游离酶的38.1倍和25.2倍,是Novozym 435比活力的50.3倍和110.8倍。 (4)微球和纳米纤维固定化脂肪酶CALB分别与游离葡萄糖氧化酶偶联催化油酸的环氧化反应,以中空纳米纤维固定化CALB催化偶联反应的活力最高,且具有良好的重复使用稳定性,重复使用40次以后活力收率仍可达到60%。
Other AbstractThe epoxidation reaction of double bond in unsaturated fatty acids could be effectively catalyzed by lipase in the existence of H2O2, thus producing epoxy vegetable oil and epoxy fatty acids with extensive application prospects. Unfortunately, the enzyme was seriously inactivated by contact with H2O2 and in situ generated peroxyacid. Immobilization was therefore necessary to improve the enzyme stability. In this study, lipase was immobilized with different microparticles and nanofibers, and subsequently catalyzed epoxidation reaction of oleic acid in nonaqueous system and biphasic system, respectively. The reaction activity and reusability of immobilized lipase were studied. Furthermore, immobilized lipase was also coupled with free glucose oxidase (GOD). The results were as follows: (1) The epoxidation of oleic acid was catalyzed by different lipases. Candida Antarctica Lipase B (CALB) exhibited the highest specific activity, and was therefore selected to catalyze the epoxidation reaction in the following studies. (2) CALB was absorbed or covalent binded on 8 kinds of microspheres. The highest loading amount of 100.7mg/g was obtained when CALB was absorbed on hydrophobic mesoporous PST30 microspheres, while the highest activity and stability were obtained by CALB loading on hydrophobic gigaporous PST microspheres. The activity of CALB-loaded PST microspheres was 1.8 and 7.3 times higher than that of Novozym 435 when catalyzed in nonaqueous and biphasic system separately. In addition, the reusability of CALB-loaded PST microspheres was comparable to that of Novozym 435. (3) CALB was immobilized on polyurethane (PU) nanofibers and PU hollow nanofibers. CALB entrapped in hollow nanofibers exhibited the highest activity and stability, which were separately 50.3 and 110.8 times higher than that of Novozym 435 when catalyzed in nonaqueous system and biphasic system. (4) The epoxidation reaction could be catalyzed by immobilized CALB coupled with free GOD. CALB entrapped in hollow nanofibers showed the highest activity and reusability when coupled with GOD. After 40 cycles, CALB entrapped in hollow nanofibers still retained 60% of its activity.
Document Type学位论文
Recommended Citation
GB/T 7714
樊亚超. 固定化脂肪酶催化油酸环氧化的研究[D]. 中国科学院研究生院,2013.
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