Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
Department of Biotechnology Engineering, Braude College of Engineering, Karmiel 2161002, Israel.
Int J Mol Sci. 2022 Oct 12;23(20):12122. doi: 10.3390/ijms232012122.
Lipase-catalyzed transesterification is prevalent in industrial production and is an effective alternative to chemical catalysis. However, due to lipases' unique structure, the reaction requires a biphasic system, which suffers from a low reaction efficiency caused by a limited interfacial area. The use of emulsion particles was found to be an effective way to increase the surface area and activity. This research focuses on cellulose as a natural surfactant for oil-in-water emulsions and evaluates the ability of lipase, introduced into the emulsion's aqueous phase, to integrate with the emulsion microparticles and catalyze the transesterification reaction of high molecular weight esters dissolved in the particles' cores. Cellulose-coated emulsion particles' morphology was investigated by light, fluorescence and cryogenic scanning electron microscopy, which reveal the complex emulsion structure. Lipase activity was evaluated by measuring the hydrolysis of emulsified -nitrophenyl dodecanoate and by the transesterification of emulsified methyl laurate and oleyl alcohol dissolved in decane. Both experiments demonstrated that lipase introduced in the aqueous medium can penetrate the emulsion particles, localize at the inner oil core interface and perform effective catalysis. Furthermore, in this system, lipase successfully catalyzed a transesterification reaction rather than hydrolysis, despite the dominant presence of water.
脂肪酶催化的酯交换反应在工业生产中普遍存在，是化学催化的有效替代方法。然而，由于脂肪酶独特的结构，反应需要双相体系，由于界面面积有限，反应效率较低。研究发现，使用乳液颗粒是增加表面积和活性的有效方法。本研究以纤维素作为油包水乳状液的天然表面活性剂，评估了引入乳液水相的脂肪酶与乳液微颗粒结合并催化溶解在颗粒核心中的高分子量酯的转酯化反应的能力。通过光、荧光和低温扫描电子显微镜研究了纤维素包覆乳液颗粒的形态，揭示了复杂的乳液结构。通过测量乳化的对硝基苯十二酸酯的水解和乳化的溶解在正十二烷中的月桂酸甲酯和油醇的转酯化来评估脂肪酶的活性。这两个实验都表明，引入水相中的脂肪酶可以穿透乳液颗粒，定位于内部油核界面，并进行有效的催化。此外，在该体系中，尽管水的存在占主导地位，但脂肪酶仍成功地催化了转酯化反应，而不是水解反应。
