Novel enzyme materials-utilizing in organic media

在过去的十年里，由于与在水中相比，在有机介质中具有一些显着的新奇性质，酶在有机介质中的应用引起了人们的极大兴趣。生物催化剂工程已成功地应用于有机介质中的生物催化，获得稳定的生物催化剂是生物技术的主要目标。在非水溶剂中，酶可以催化酯化、类固醇转化和多肽形成等疏水化合物的合成反应。与传统的化学合成方法相比，酶转化具有极高的底物专一性和反应活性。然而，为了充分利用有机介质中的生物催化作用，从减少底物的扩散限制和提高反应速度的角度出发，有必要将酶修饰成可溶于有机溶剂的酶。Al…此外，虽然在悬浮状态下使用粉末酶很简单，但由于不均匀，反应速度通常很低，需要几天时间才能获得高反应产率。本研究开发了一种利用油包水乳状液制备表面活性剂-酶复合体的新方法。研究了获得合适的表面活性剂-脂肪酶复合体的制备条件。利用表面活性剂-脂肪酶络合物，在有机溶剂中对苯甲醇和月桂酸进行了酯化反应。将脂肪酶包埋在表面活性剂基质中，可显著提高脂肪酶在疏水有机溶剂中的酶活。在有机介质中，表面活性剂-脂肪酶复合体能很好地催化酯化反应。表面活性剂-脂肪酶复合体的酯化速率远高于粉末状脂肪酶。脂肪酶复合体的活性强烈地依赖于包埋的表面活性剂和制剂中的水溶液pH。与天然脂肪酶相比，表面活性剂-脂肪酶复合体在高温下具有较好的热稳定性。此外，该脂肪酶复合体具有较高的储存稳定性。这种修饰方法将使我们能够利用许多在有机介质中没有表现出酶活性的酶作为新的生物催化剂。较少

The utility of enxymes in organic media has attracted much interest during the last ten years due to some remarkable novel properties compared to those in water. Biocatalyst engineering has been used successfully to improve biocatalysis in organic media and obtaining stable biocatalysts is a main target of biotechnology. Enzymes in nonaqueous solvents can catalyze a synthesis reaction of hydrophobic compounds such as esterification, steroid conversions and peptide formation. The substrate specificity and reactivity in an enzyme conversion are extremely high compared with those of conventional chemical synthesis. Thus an application of enzymatic reaction has been expected to produce optically active materials with an industrial scale.However, in order to take full advantage of the biocatalysis in organic media, it is necessary to modify the enzyme to be soluble in an organic solvent from the viewpoint of reduced diffusional limitations of substrates and increase in the reaction rate. Al … More though using a powder enzyme in a suspension state is simple, the reaction rate is usually very low due to the heterogeneity and several days are required to attain a high reaction yield. In this study, a novel preparation method for surfactant-enzyme complexes has been developed utilizing water-in-oil emulsions. Preparation conditions to obtain a suitable surfactant-lipase complex were investigated. Using the surfactant-lipase complexes, the estarification of benzyl alcohol with lauric acid was conducted in organic solvents. The enzymatic activity of lipase in a hydrophobic organic solvent was significantly enhanced by entrapping in a surfactant matrix. The surfactant-lipase complex catalyzed the esterification effect ively in organic media. The esterification rate from the surfactant-lipase complex was much higher than that from the powder lipase. The activity of the lipase complex strongly depends on the entrapping surfactant and the aqueous pH in the preparation. The surfactant-lipase complexes were thermostable at high temperature compared to the native lipase. Furthermore, the lipase complex showed a high storage stability. This modification method will enable us to utilize a lot of enzymes as new biocatalysts which had not shown enzymatic activity in organic media. Less