生物表面活性剂用于逆胶束体系的构建及微水相条件优化

摘要

对生物表面活性剂应用于逆胶束体系构建及微水相的条件优化进行了研究.通过与化学表面活性剂(阳离子表面活性剂CTAB、阴离子表面活性剂AOT、非离子表面活性剂TWTween-80)的对比可知,生物表面活性剂鼠李糖脂RL具有高增溶性、低使用量、微环境所需条件温和等优点.通过荧光法测得RL在异辛烷中的临界胶束浓度CMC为0.055mmol/L,相对于化学表面活性剂需要更少的量即可形成逆胶柬.电导法测得其最佳含水率W为32.1,比其他逆胶束的最佳含水率大,表明其能够增溶更多的水,导致了RL构建的逆胶束粒径相对其他胶体的大,这也为酶解反应提供了足够的反应空间.本实验也通过紫外法测定了pH、离子强度对于逆胶束中漆酶活性的影响,RL体系的最佳pH为5.2、最佳KCI浓度为0.05mol/L,pH与离子强度分别是通过酸碱度、带电电荷与表面活性剂极性端相互作用来影响酶活.%Construction of reversed micelle (RM) by biosurfactant and the optimization of its microenvironment have been investigated. Compared with three kinds of chemical surfactants (cation surfactant: CTAB, anion surfactant: AOT nonion surfactant:Tween-80), rhamnolipid (RL), a typical biosurfactant, has the advantages of higher solubilization ability for water, lower dosage in the construction of RM, milder microenvironment for construction and so on. The Critical Micelle Concentration(CMC) of RL solubilized in isooctane detected through the method of fluorescence was 0.055mmol/L, therefore RM could be constructed by it with relatively lower dosage. It was found that the optimum hydration degree Wwas 32.1 through conductivity measurement, higher than the optimum hydration degree of other RMs, indicating that RL could highly increase the water solubility. Therefore, the RM constructed by RL had larger particle diameter than other ones, which also supplied sufficient space for enzymolysis reaction. UV spectrum was analysed to find out how pH and ionic strength affected enzyme activity of laccase in RM. And it has been found that while the pH was 5.2, the concentration of K.C1 was O.Osmol/L, the optimal condition of RL system could be reached. pH and ionic strength impacted the enzyme activity through the interaction between polar end of surfactant and pH value as well as charge of the microenvironment.