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高温热解制备磁性Fe_3O_4纳米粒并修饰羧基后作为载体,以EDCl作为游离羧基活化剂、NHS为活性羧基稳定剂,对脂肪酶进行共价固定化和稳定性研究。结果表明:制备的磁性纳米粒直径约21 nm,羧基修饰量为0.90×10~(-4) mmol/mg。优化的固定化条件为:对1 m L含铁5 mg/m L的羧基化Fe_3O_4纳米粒溶液,EDCl和NHS用量均为5.8×10~(-4) mmol,脂肪酶添加量为7 mg,反应时间1 h,得到的固定化酶冻干粉表观比酶活为1.03 U/mg。与游离脂肪酶相比,该固定化酶具有很好的存储、p H和热稳定性,循环水解橄榄油6次后,酶活回收率仍可保持65%。
High temperature pyrolysis preparation of magnetic Fe_3O_4 nanoparticles and carboxyl modified as a carrier, with EDCl as a free carboxyl activator, NHS as an active carboxyl stabilizer, lipase covalent immobilization and stability studies. The results showed that the diameter of magnetic nanoparticles was about 21 nm and the amount of carboxyl groups was 0.90 × 10 -4 mmol / mg. The optimum immobilization conditions were: the amount of EDCl and NHS was 5.8 × 10 ~ (-4) mmol, the amount of lipase added was 7 mg for 1 m L iron-containing 5 mg / m L carboxylated Fe 3 O 4 nanoparticles solution, The reaction time was 1 h, and the apparent specific activity of immobilized enzyme freeze-dried powder was 1.03 U / mg. Compared with the free lipase, the immobilized enzyme has good storage, pH and thermal stability. After 6 cycles of hydrolyzed olive oil, the enzyme activity recovery can still be maintained at 65%.