乳糖酶交联酶聚体的制备及性能

Preparation and properties of cross-linked enzyme aggregates(CLEAs) of β-galactosidase

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(20 h)后活力可保留52%。

Two kinds of cross-linked enzyme aggregates （CLEAs） of fl-galactosidase from Kluyveromyces lactis and Aspergillus oryzae were prepared by using dialdehyde 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 fl-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 ℃.