Solvent Engineering on Enzymatic Synthesis of Edible Surfactants

以食品中的亲水性和疏水性成分为原料，研究了酶法合成可食性表面活性剂的工艺。在本研究的第一阶段，进行了β-葡萄糖苷酶催化合成烷基葡萄糖苷，以了解在这种合成反应中发生的现象，虽然葡萄糖苷是不可食用的，但具有广泛的工业用途。在传统的水-有机两相体系中，底物之一乙醇本身为有机相，提出了预测目标产物和副产物产率的方程。结果表明，葡萄糖与乙醇缩合反应的平衡常数与醇的烷基链长无关。我们提出了一种新的反应体系，其中固体酶和葡萄糖被添加到用缓冲液饱和的乙醇中。烷基糖苷的平衡产率在该系统中是远远高于在传统的两相系统。酶在系统中的高稳定性允许其在随后的缩合中重复使用。在该体系中，仲醇的（R）-和（S）-异构体均能与葡萄糖发生缩合反应，并以较高的产率得到相应的糖苷。找到了一种高效液相色谱分离烷基糖苷和醇的填料。提出了一个模型来解释溶质的洗脱时间依赖于洗脱液的组成。本文提出了仅从溶质的脉冲响应曲线估算溶质在吸附剂上的吸附等温线的简单方法。研究了固定化脂肪酶对甜菜碱和抗坏血酸的酰化反应。酰化反应在水含量极低的乙腈中立体选择性地进行。产物通过NMR分析鉴定为所需产物。

Enzymatic synthesis of edible surfactants from hydrophilic and hydrophobic ingredients in food was invesigated. In the first stage of this investigation, b-glucosidase-catalyzed synthesis of alkyl glucosides was made to understand phenomena occuring in such synthetic reaction, although the glucosides are not edible but have a wide range of industrial use. We proposed the equations to predict the yields of desired product and by-products in a conventional aqueous-organic biphasic system, where one of substrates, alcohol, itself was an organic phase. It was found that the equilibrium constant for condensation of glucose and alcohol was independent of the alkyl chain length of alcohol. We proposed a novel reaction system where solid enzyme and glucose were added to alcohol saturated with a buffer. The equilibrium yield of alkyl glucoside in the proposed system was much higher than that in the conventional two-phase system. High stability of the enzyme in the system allowed its reuse in subsequent condensation. It was also found in the system that both of (R) -and (S) -isomers of secondary alcohol could be condensed with glucose by the enzyme to give corresponding glucosides in high yield. A packing material for effective liquid-chromatographic separation of alkyl glucoside and alcohol was found out. A model was proposed to explain the dependence of elution times of solutes on the composition of eluent. Simple methods were proposed for estimation of adsorption isotherm of a solute on an adesorbent from only a pulse response curve ofthe solute. Acylation of erythritol and ascorbic acid by immobilized lipase was also examined. The acylation proceeded stereoselectively in acetonitril with extremely low content of water. The products were identified to be desired products by NMR analysis.