Department of Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong.
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, P. R. China.
Chem Asian J. 2018 Nov 16;13(22):3533-3539. doi: 10.1002/asia.201800853. Epub 2018 Aug 21.
Herein, we report the utilization of a submicron Pickering emulsion (SPE) for the encapsulation of enzymes (e.g., lipase from Candida sp.) in water droplets that were solely stabilized by hydrophobic solid or mesoporous silica nanoparticles in toluene for use in biphasic reactions. The catalytic performance of encapsulated lipase was evaluated in the esterification of 1-hexanol and hexanoic acid under stirring-free conditions, which was favorable for maintaining enzymatic activity. Remarkably, the SPE significantly increased the specific activity of encapsulated lipase, owing to the exceptionally high water/oil interfacial area and short diffusion distance of the reagents in the SPE. With mesoporous silica nanoparticles, the activity of lipase was approximately 25.5- and 2.8-times higher than that of free lipase and encapsulated lipase in the micron Pickering emulsion, respectively. The higher water/toluene interfacial area was attributed to the smaller submicron-scale water droplets and the increase in the mass transfer of enzymes or substrates was further improved by using mesoporous Pickering stabilizers. In addition, the encapsulated lipase in SPE also demonstrated excellent stability and could be recycled up to 15 times without significant loss of activity.
本文利用亚微米级 Pickering 乳液（SPE）将酶（如 Candida sp. 脂肪酶）包封在甲苯中的疏水固体或介孔硅纳米粒子稳定的水相中，用于两相反应。在无搅拌条件下，评估了包封脂肪酶在 1-己醇和己酸酯化反应中的催化性能，这有利于保持酶的活性。值得注意的是，SPE 显著提高了包封脂肪酶的比活性，这是由于 SPE 中试剂具有极高的水/油界面面积和较短的扩散距离。使用介孔硅纳米粒子时，脂肪酶的活性分别比游离脂肪酶和微米级 Pickering 乳液中包封的脂肪酶高约 25.5 倍和 2.8 倍。更高的水/甲苯界面面积归因于更小的亚微米级水相，并且通过使用介孔 Pickering 稳定剂进一步提高了酶或底物的传质。此外，SPE 中的包封脂肪酶也表现出优异的稳定性，可回收使用 15 次以上而活性无明显损失。
