Yu Xinxin, Li Qian, Wang Miaomiao, Du Na, Huang Xirong
Key Laboratory of Colloid & Interface Chemistry of the Education Ministry of China, School of Chemistry and Chemical Engineering Shandong University, Jinan 250100, P. R. China.
Soft Matter. 2016 Feb 14;12(6):1713-20. doi: 10.1039/c5sm02704g. Epub 2015 Dec 21.
To formulate a compatible green medium for the conversion of a hydrophobic substrate by a hydrophilic enzyme, we investigated the phase behavior of pseudo ternary hydrophobic ionic liquid (HIL)/buffer/polyoxyethylene-type nonionic surfactant (CnEm)/n-alcohol system and the effects of the components on the formulation of the HIL-based bicontinuous microemulsion. It is found that small head group of the surfactant, high concentration of n-alcohol (medium/long alkyl chain) and low cohesive energy density of the HIL result in low phase transition temperature. In the CnEm stabilized compatible bicontinuous microemulsion, the kinetics of laccase catalyzed oxidation of 2,6-dimethoxyphenol were also investigated. It is found that in addition to temperature, n-alcohol is the key parameter affecting the catalytic performance of laccase, and the optimum n-alcohol depends on the type of HIL as an oil phase. All the kinetic parameters, such as Km, kcat, kcat/Km, and Ea (apparent activation energy), indicate that the bicontinuous microemulsion consisting of [Omim]NTf2/buffer/CnEm/n-hexanol is a suitable medium for the laccase-catalyzed reaction. To the best of our knowledge, this is the first report on the formulation of HIL-based bicontinuous microemulsion for enzyme catalysis.
为了配制一种适合亲水性酶转化疏水性底物的绿色介质，我们研究了伪三元疏水离子液体（HIL）/缓冲液/聚氧乙烯型非离子表面活性剂（CnEm）/正醇体系的相行为以及各组分对基于HIL的双连续微乳液形成的影响。研究发现，表面活性剂的小头基、高浓度的正醇（中/长烷基链）和HIL的低内聚能密度导致低相变温度。在CnEm稳定的相容性双连续微乳液中，还研究了漆酶催化氧化2,6-二甲氧基苯酚的动力学。研究发现，除了温度外，正醇是影响漆酶催化性能的关键参数，最佳正醇取决于作为油相的HIL的类型。所有动力学参数，如Km、kcat、kcat/Km和Ea（表观活化能），均表明由[Omim]NTf2/缓冲液/CnEm/正己醇组成的双连续微乳液是漆酶催化反应的合适介质。据我们所知，这是关于用于酶催化的基于HIL的双连续微乳液配方的首次报道。
