γ-Fe_2O_3-凹土超顺磁性纳米复合材料固载猪胰脂肪酶

Immobilization of porcine pancreatic lipase on superparamagnetic γ-Fe_2O_3-attapulgite nanocomposites

以凹凸棒石黏土为原料,制备γ-Fe2O3-凹土超顺磁性纳米复合材料(γ-Fe2O3-ATP)作为猪胰脂肪酶(PPL)固定化的载体,利用透射电子显微镜(TEM)、N2吸附脱附等温图(BET)、振动试样磁强计(VSM)等对材料进行表征,同时对固定化条件和固定化酶的相关性质进行了研究。结果表明:制备的γ-Fe2O3-ATP是介孔材料,比表面积为102.63 m2/g,平均孔径为10.862 nm,饱和磁化强度为8.915 emu/g,其作为载体能实现固定化酶与反应介质简单、快速分离回收和重复利用。在固定化时间为4 h及pH 6.0时制备的固定化酶效果最佳;经过6 h高温保存后固定化酶可保留初始酶活的52%,而游离酶仅保留初始酶活的19%,同时固定化酶在重复使用5次后酶活仍保留初始酶活的60%。

The porcine pancreatic lipase（ PPL） was immobilized on superparamagnetic γ-Fe2O3-attapulgite nanocomposites （ γ-Fe2 O3-ATP ） . The γ-Fe2 O3-ATP was characterized with transmission election microscopy （ TEM ） , BET and VSM. The immobilization conditions and enzymatic properties of immobilized PPL were investigated. The results showed that the γ-Fe2 O3-ATP was mesoporous material,specific surface area was 102.63 m2/g,average pore diameter was 10.862 nm, and saturation magnetization was 8.915 emu/g. The optimal immobilization conditions were determined to be pH 6.0 and immobilization time was 4 h. The thermal stability of the immobilized enzyme was enhanced compared with the free enzyme. The residual activity was kept at 52% for 6 h, while that of the free enzyme was just 19%. The catalytic activity of immobilized enzyme was kept at 60% after 5 batch reactions. Enzymes supported on superparamagnetic γ-Fe2O3-ATP could be easily separated and reused.