Biocatalytic synthesis represents a green alternative to metal-catalyzed reactions. However, enzymes typically display much lower catalytic activities in nonaqueous solvents than in aqueous media. To mimic the aqueous environment for enzyme activation, this study designed a series of sixteen dual-functionalized ionic liquids (ILs) that comprising both glycol ether (hydrogen-bond acceptor) and tert-alcohol (hydrogen-bond donor) groups. These “water-like” ILs enabled high transesterification activities for immobilized Candida antarctica lipase B (CALB) known as Novozym 435 and immobilized Bacillus licheniformis protease (known as subtilisin A) respectively. Several water-mimicking ILs containing 2–3 v% water significantly increased the CALB activity by 1.8-fold of that in tert-butanol, and 1.6-fold of that in diisopropyl ether (both organic solvents are highly enzyme-compatible). To a smaller degree, subtilisin was activated by these ionic solvents up to 1.2-fold (with 100% selectivity at 2 v% water) than by diisopropyl ether. Fluorescence emission spectra suggested that the characteristic emission maximum peaks were maintained in “water-like” ILs in most cases.

生物催化合成代表了金属催化反应的绿色替代品。然而，酶在非水溶剂中的催化活性通常比在水介质中低得多。为了模拟酶激活的水性环境，本研究设计了一系列 16 种双功能化离子液体 (IL)，其中包含乙二醇醚（氢键受体）和叔醇（氢键供体）基团。这些“水样”ILs 使固定化南极假丝酵母脂肪酶 B (CALB) 称为 Novozym 435 和固定化地衣芽孢杆菌具有高酯交换活性蛋白酶（称为枯草杆菌蛋白酶 A）。几种含有 2-3 v% 水的仿水 IL 使 CALB 活性显着提高了叔丁醇中的 1.8 倍，以及二异丙醚中的 1.6 倍（两种有机溶剂都具有高度的酶相容性）。在较小程度上，这些离子溶剂对枯草杆菌蛋白酶的活化是二异丙醚的 1.2 倍（在 2 v% 的水中具有 100% 的选择性）。荧光发射光谱表明，在大多数情况下，特征发射最大峰保持在“类水”离子液体中。