On the nature of ionic liquids and their effects on lipases that catalyze ester synthesis

High transesterification activities of immobilized proteases in new ether-functionalized ionic liquids

“…The proteases in more water-rich ILs (2-4) are expected to be in more flexible and active forms, which lead to high enzyme activity and selectivity. De Diego et al (2009) reported a similar finding: a low water activity (a w ) was found in [CPMA][MeSO 4 ] at a high water content (for example, a w \ 0.5 at 8% (v/v) water content), where the IL acted as a water activity depressing agent because of the strong interaction between water and the IL molecules. Therefore, the high water content does not necessarily lead to product hydrolysis because of the lack of 'free' water molecules, but shifts the reaction to synthetic pathway.…”

“…The Xu group (Guo et al 2006) judiciously selected a group of commercial tetraammoniumbased ILs (Ammoeng series) as reaction media for the enzymatic glycerolysis; these ether-functionalized ILs are ionic mixtures containing multiple alkoxy groups, which have both hydrophilic and hydrophobic properties like polyethylene glycol (PEG). De Diego et al (2009) also reported the high synthetic activity of free Candida antarctica lipase B (CALB) in ether-functionalized Ammoeng 100 (also known as [CPMA][MeSO 4 ]). Dreyer and Kragl (2008) observed the ether-functionalized Ammoeng 110 was effective in forming aqueous two-phase system for the purification of two alcohol dehydrogenases, and this IL was capable of stabilizing enzymes and enhancing the solubility of hydrophobic substrates.…”

Cloning of Synthetic Lipase Gene from Rhizomucor miehei with Original Signal Peptide in Pichia pastoris

“…Lipases has been successfully applied in various applications, such as in the food industry, organic synthesis, pharmaceutical (Houde et al 2004;Diego et al 2009) and in the field of biodiesel (Huang et al 2012;Huang et al 2014). The success is challenging us to keep looking for a better lipase expression with the aid of genetic engineering.…”

Progress of Lipase-Catalyzed Ester Synthesis in Ionic Liquid

“…在一定的范围 内, 离子液体的疏水性越大, 水分子与酶的相互作用力 越强, 酶的空间结构越稳定 [40] ; 但当离子液体的疏水性 超过界限值后, 酶活性随着离子液体疏水性增大而降 低, 原因在于离子液体的疏水性过高会抑制底物与酶分 子的相互接触, 降低底物在离子液体中的溶解度, 阻碍 底物与酶分子的相互作用 [41] . 而"在亲水性离子液体-酶"组成的微环境中(图 1b), 离子液体由于本身具有更 高的介电常数, 从而取代结合在酶表面的水分子, 引起 脂肪酶的肽链解折叠, 最终表现为酶的活性降低甚至失 活 [3] . 图 1 疏水性和亲水性离子液体对酶表面微环境的影响 Figure 1 Hydrophobic and hydrophilic ILs' effects on microenvironment on the surface of lipase Rubio 等 [42] 在离子液体中以向日葵和废弃食用油为 原料进行酯交换反应, 结果表明 CaLB 在亲水性较强的 [5] .…”