Department of Biotechnology Engineering, Kolhapur Institute of Technology's College of Engineering, Kolhapur 416 234, India.
Bioresour Technol. 2012 Nov;123:542-7. doi: 10.1016/j.biortech.2012.07.044. Epub 2012 Jul 22.
Novel magnetic cross-linked enzyme aggregates of alpha amylase were prepared by chemical cross-linking of enzyme aggregates with amino functionalized magnetite nanoparticles which can be separated from reaction mixture using magnetic field. Of the initially applied alpha amylase activity 100% was recovered in magnetic CLEAs, whereas only 45% was recovered in CLEAs due to the low content of Lys residues in alpha amylase. Scanning electron microscopy analysis showed that CLEAs and magnetic CLEAs were spherical structures. The CLEAs and magnetic CLEAs displayed a shift in optimal pH towards the acidic side, whereas optimal temperature of magnetic CLEAs was improved compared to free enzyme and CLEAs. Although V(max) of enzyme in CLEAs and magnetic CLEAs did not change, substrate affinity of the enzyme increased. The magnetic CLEAs also enhanced the thermal stability and storage stability. Moreover, the magnetic CLEAs retained 100% initial activity even after 6 cycles of reuse.
新型磁性交联酶聚集体通过用氨基功能化的磁铁矿纳米粒子对酶聚集体进行化学交联制备，这些纳米粒子可以用磁场从反应混合物中分离出来。在最初应用的α-淀粉酶活性中，100%在磁性 CLEAs 中得到回收，而在 CLEAs 中仅回收了 45%，这是由于α-淀粉酶中赖氨酸残基的含量低。扫描电子显微镜分析表明，CLEAs 和磁性 CLEAs 均为球形结构。与游离酶和 CLEAs 相比，CLEAs 和磁性 CLEAs 的最适 pH 值向酸性方向偏移，而磁性 CLEAs 的最适温度得到了提高。尽管 CLEAs 和磁性 CLEAs 中的酶 Vmax 没有改变，但酶的底物亲和力增加了。磁性 CLEAs 还增强了热稳定性和储存稳定性。此外，磁性 CLEAs 在经过 6 次重复使用后仍保留 100%的初始活性。
