The Study on Enzymic Synthesis of Sugar-Fatty Acid Ester

研究了假丝酵母脂肪酶催化糖与油酸的酯化反应，并考察了脂肪酶的酯化转化率。以山梨醇、赤藓糖醇、木糖醇、甘露醇和肌醇等糖醇的饱和水溶液为底物。该反应在具有受控的非常小的水含量的反应体系中进行。在木糖醇、山梨醇、赤藓糖醇和甘露糖醇的情况下获得高转化率，特别是在木糖醇和山梨醇中获得超过80%的转化率。DSC和紫外光谱分析表明，酯化反应发生在脂肪酸与糖溶液的界面上。当反应体系含水量降低时，界面糖浓度增加，反应速率加快，平衡向酯化方向移动，转化率提高。糖醇类产品 ...更多信息 转化率高于蔗糖，但环糖醇如肌醇转化率低。糖和糖醇的碳数越小，转化率越大。酯化所需的最低水含量估计为300 - 4000 ppm。在这些情况下，反应体系中的水与酶蛋白结合，并且需要该水来支持三维结构和酶活性。结果表明，脂肪酶的酯化转化率受糖醇在油酸-水界面上的吸附量的影响，其吸附量与糖醇的浓度和吸附平衡常数成正比，为了使脂肪酶在生物反应器中连续产酯，脂肪酶必须吸附在不溶性载体上。结果表明，脂肪酶能够包埋在由N-异丙基丙烯酰胺悬浮单体聚合而成的高分子凝胶中。通过这种固定化，酶对温度和pH的稳定性增加。然后研究了等离子体技术将脂肪酶固定化到引入氨基或甲基丙烯酸缩水甘油酯基团的硅胶微球和聚苯乙烯微球的可行性。这些方法可用于脂肪酶的固定化。少

The enzymic eaterification reaction between sugar and oleic acid was examined by using the lipase from Candida Cylindracea and the conversion to the ester was investigated. The saturated aqueous solution of sugar alcohols such as Sorbitol, Erithritol, Xylitol, Mannnitol and Inositol were used as substrates. The reaction was carried out in a reaction system with a controlled very small water content. High cinversion was obtained in the case of Xylitol, Sorbitol, Erithritol and Mannitol, especially over 80% of conversion was attained in Xylitol and Sorbitol. From the result of DSC and UV-spectrum analysis, it seemed that the esterification reaction occurred at the interface between fatty acid and aqueous solution of sugars. When the water content of the reaction system was decreased, the concentration of the sugars at interface became higher and the reaction rate inceased, high conversion was obtained simultaneously by a shift of the equilibrium to the esterification. Sugar alcohols prod … More uced a higher conversion than sugar, but the ring sugar alcohol such as Inositol produced low conversion. The smaller the carbon number of the sugar and sugar alcohol, the greater the conversion. The minimum level of water content needed for esterification was estimated at the range of 300 to 4000 ppm. In these cases the water in the reaction system was bound to the enzyme protein and this water was needed to support the three-dimensional structure and the enzyme activity. From these results, the esterification conversion seemed to be influenced by the adsorption amounts of the sugar alcohol to the interface between water and oleic acid, and the amounts increased proportionally to the concentration and adsorption equilibrium constant of the sugar alcohol.In order to produce the ester by the bioreactor continuously the lipase have to immobilize in the insoluble carrier. It was clear that the lipase was able to entrap in to the high molecular gels which were obtained by polymerization of suspended monomer, N-isopropylacrylamide.. The stability of the enzyme to the temperature and pH increase by this immobilization. And then the feasibility of immobilization of the lipase to silica and polystylene microspheres to which the amino or glycidyl methacylate group were introduced by plasma technique was investigated. These methods were available for the immobilization of lipase. Less