Porous nanomaterials are of great significance in enzyme immobilization by addressing the intrinsic issues of the native form of enzymes, such as low enzymatic activity and reusability. In this work, we report the successful fabrication of benzene-bridged dendritic mesoporous organosilica nanoparticles (BDMONs) with highly enriched benzene groups in the pore channel wall by a delayed addition method. The developed BDMONs were explored as nano-carriers for lipase immobilization. This platform exhibited a specific activity 6.5 times higher than that of the free enzyme with an excellent reusability, and enhanced thermal and pH stability. It is demonstrated that both the hydrophobic benzene groups and dendritic large-pores are responsible for the superior performance of the immobilized lipase in comparison with dendritic mesoporous silica nanoparticles, ethane-bridged dendritic mesoporous organosilica nanoparticles, and benzene-bridged MONs without large-pores. In particular, the designed nanobiocatalyst functions better than the free enzyme in the transesterification of corn oil to produce biodiesel, showing 93% conversion in the first cycle while retaining 94% of the initial catalytic activity after 5 cycles.

中文翻译：

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设计合成用于酶促生物柴油生产的有机二氧化硅纳米颗粒

多孔纳米材料通过解决酶天然形式的内在问题，例如低酶活性和可重复使用性，在酶固定中具有重要意义。在这项工作中，我们报告了通过延迟添加方法成功制备了在孔道壁中具有高度富集的苯基的苯桥的树枝状介孔有机二氧化硅纳米粒子（BDMONs）。已开发的BDMONs被研究为用于脂肪酶固定化的纳米载体。该平台具有比游离酶高6.5倍的比活性，具有出色的可重复使用性，并具有增强的热稳定性和pH稳定性。结果表明，与树枝状介孔二氧化硅纳米粒子，乙烷桥接的树枝状介孔有机二氧化硅纳米粒子和无大孔的苯桥接的MONs相比，疏水性苯基和树枝状大孔都对固定化脂肪酶的优异性能负责。特别地，设计的纳米生物催化剂在玉米油的酯交换反应生产生物柴油中的功能优于游离酶，在第一个循环中显示93％的转化率，而在5个循环后保留94％的初始催化活性。