乳糖酶交联酶聚体的制备及性能

摘要

Two kinds of cross-linked enzyme aggregates (CLEAs) of /?-galactosidase from Kluyveromyces lactis and Aspergillus oryzae were prepared by using di aldehyde starch (DAS) as cross-linker. Adding bovine serum albumin ( BSA) as protective agent was helpful to raise the activity of CLEAs. In the condition of DAS mass fraction 10% , oxidation degree 80% and mass ratio of enzyme to BSA 1 : 8, the obtained activity residues of K. Lactis and A. Oryzae β-galactosidase CLEAs were 53. 84% and 55. 25% respectively. The optimum pH values of the two CLEAs were both decreased. A. Oryzae β-galactosidase CLEAs presented a high thermal stability at 60℃ ,with its activity retained about 52% after repeated using for 5 cycles (20 h) at 37 ℃.%以双醛淀粉(DAS)为交联剂,分别制备了乳酸克鲁维酵母和米曲霉来源的乳糖酶交联酶聚体(CLEAs),同时添加牛血清白蛋白(BSA)作为保护剂以提高 CLEAs 活性.当 DAS 质量分数为10％、氧化度为80％、BSA 与酶蛋白质量比为1:8时得到的酵母和曲霉乳糖酶 CLEAs 的活力保留分别为53.84％和55.25％.CLEAs 的最适pH值较游离酶有所降低.曲霉乳糖酶CLEAs在60℃下具有较好的热稳定性,并且在37℃下重复使用5次(20h)后活力可保留52％.