Department of Engineering, University of Aarhus, Aarhus C DK-8000, Denmark.
Department of Engineering, University of Aarhus, Aarhus C DK-8000, Denmark; Department of Food Science, Institute of Ocean Research, Ocean College, Zhejiang University of Technology, Chaowang Rd 18, Hangzhou 310014, China.
Food Chem. 2020 Apr 25;310:125858. doi: 10.1016/j.foodchem.2019.125858. Epub 2019 Nov 9.
This work established a binary ionic liquid-solvent system for effective enzymatic esterification of naturally occurring phenolic glycosides (flavonoids); which could result in a dramatic enhancement of Novozym 435-catalyzed esterification of esculin, demonstrating a great synergetic effect. In essence, [OMIM][BF]-toluene and [TOMA][TfN]-hexane binary systems both served >90 mol% of conversions of esculin after 96 h of reaction at 60 °C. Typically, binary [TOMA][TfN]-hexane system enabled Novozym 435 with extremely high catalytic efficiency (k/K = 17.57 × 10 (Ms)), which was 55-fold higher than that Novozym 435 exhibited in t-butanol solvent (one of the best solvent systems for esterification reactions). It was also found that the superiormatching in property and structure between IL and solvent was the decisive factor for the outperformance of [TOMA][TfN]-hexane binary system, in which [TOMA] and hexane facilitate the solubilization of esculin and fatty acids and [TfN] anions and hexane offer protective effects for lipase at elevated temperatures.
本工作建立了一种用于有效酶酯化天然存在的酚糖苷（类黄酮）的双离子液体-溶剂体系；这可能导致 Novozym 435 催化芦丁酯化反应的显著增强，表现出很大的协同效应。本质上，[OMIM][BF]-甲苯和[TOMA][TfN]-己烷二元体系在 60°C 反应 96 小时后，均可实现芦丁>90mol%的转化。通常，双[TOMA][TfN]-己烷体系使 Novozym 435 具有极高的催化效率（k/K=17.57×10（Ms）），比 Novozym 435 在叔丁醇溶剂（酯化反应的最佳溶剂体系之一）中表现出的效率高 55 倍。还发现，离子液体和溶剂在性质和结构上的超级匹配是[TOMA][TfN]-己烷二元体系表现优异的决定性因素，其中[TOMA]和己烷有助于芦丁和脂肪酸的溶解，[TfN]阴离子和己烷在高温下为脂肪酶提供保护作用。
