SBA-15固定化脂肪酶催化合成棕榈酸乙酯的研究
发布时间：2018-11-17 09:22
【摘要】：棕榈酸乙酯作为一种香精、香料，主要被用来作为乳化剂、生物柴油和食品添加剂等广泛使用。但是截止目前为止，对于棕榈酸乙酯的合成研究大多集中在化学催化法合成的水平上，生物酶法合成棕榈酸乙酯的文献鲜有报道，另外,采用SBA-15固定化脂肪酶，并用合成的固定化酶当作催化剂合成棕榈酸乙酯目前尚未有相关报道，属于一种新的想法。因此本研究以棕榈酸和乙醇为底物，利用氨基修饰后的分子筛SBA-15为载体，固定化猪胰脂肪酶，并以此复合物作为催化剂，利用可逆反应催化合成该酯化反应。产物经分离纯化后，采用红外、紫外等手段进行检测，并利用酸价法计算棕榈酸乙酯的产率。利用单因素实验，和响应面分析法确定了棕榈酸乙酯合成的最优条件。本篇论文研究主要包括以下几个方面： 第一部分：合成NH2-SBA-15。在酸性条件下，以三嵌段共聚物PEO20-PPO70-PEO20(P123)为模板剂，正硅酸乙酯当作硅源，采用水热法合成介孔分子筛SBA-15，并在550℃煅烧除去残留的模板剂P123。通过甲苯和APTES(3-氨丙基-三乙氧基硅烷)对合成的SBA-15进行氨基化修饰，即合成NH2-SBA-15,通过XRD、N2吸附-脱附、FTIR、TEM、SEM、TGA-DTA等分析手段对样品进行了表征。结果表明:合成的NH2-SBA-15样品仍然具有长程有序的六方孔道结构，孔径范围大概在6-8nm。 第二部分，以合成的NH2-SBA-15为载体，采用共价交联法固定化猪胰脂肪酶。考马斯亮蓝法测定酶的负载率；采用橄榄油乳化法，进行了酶活测定；另外，分别对游离酶和固定化酶的性质、稳定性进行测定，探究和优化了酶固定化的条件。经过优化分析，结果显示,合成固定化酶的最适条件为：交联时间4h，加酶量360mg/g载体，缓冲液pH7.5，温度25℃，固定化酶的负载率达82.347%，固定化酶最适温度为50℃，最适pH为7.5，最适Km为4.94%。固定化酶在重复使用6次后，剩余酶活力仍保持初始活力约70%。与游离酶相比，固定化酶具有更高负载率和更高的酶的稳定性。 第三部分，以NH2-SBA-15为载体的固定化酶作为反应的催化剂，以棕榈酸和乙醇为底物，生物催化法酯化合成棕榈酸乙酯。经单因素分析法和响应面分析法得出结论，最佳反应条件为：反应温度55.94℃，反应时间为6.72小时，乙醇体积为4.26ml。另外棕榈酸1.5g，固定化酶0.1g，，水0.5ml。采用上述优化后的工艺参数对棕榈酸乙酯进行酶法制备，棕榈酸乙酯的平均产率约为73.5%。 我们成功合成了具有较大孔径的分子筛NH2-SBA-15，以此分子筛为载体，交联法固定化猪胰脂肪酶，得到的固定化酶具有良好的稳定性，适合做非水相催化的催化剂。本实验以棕榈酸和乙醇为底物，固定化酶为催化剂，通过工艺优化合成了产率约为73.5%的棕榈酸乙酯。
[Abstract]:Ethyl palmitate, as a flavor and spice, is widely used as emulsifier, biodiesel and food additive. However, up to now, most of the studies on the synthesis of ethyl palmitate have focused on the level of chemical catalytic synthesis, and the literature on the synthesis of ethyl palmitate by biological enzyme method has been rarely reported. In addition, the immobilized lipase was immobilized by SBA-15. The synthesis of ethyl palmitate using immobilized enzyme as catalyst has not been reported, so it is a new idea. Therefore, using palmitic acid and ethanol as substrates and amino modified molecular sieve SBA-15 as carrier, porcine pancreatic lipase was immobilized and the complex was used as catalyst to synthesize the esterification by reversible reaction. After separation and purification, the product was detected by IR and UV, and the yield of ethyl palmitate was calculated by acid value method. The optimum conditions for the synthesis of ethyl palmitate were determined by single factor experiment and response surface analysis. This paper mainly includes the following aspects: the first part: synthesis of NH2-SBA-15. Under acidic conditions, mesoporous molecular sieve SBA-15, was synthesized by hydrothermal method using triblock copolymer PEO20-PPO70-PEO20 (P123) as template and ethyl orthosilicate as silicon source. The residual template P123 was calcined at 550 鈩
本文编号：2337283
[Abstract]:Ethyl palmitate, as a flavor and spice, is widely used as emulsifier, biodiesel and food additive. However, up to now, most of the studies on the synthesis of ethyl palmitate have focused on the level of chemical catalytic synthesis, and the literature on the synthesis of ethyl palmitate by biological enzyme method has been rarely reported. In addition, the immobilized lipase was immobilized by SBA-15. The synthesis of ethyl palmitate using immobilized enzyme as catalyst has not been reported, so it is a new idea. Therefore, using palmitic acid and ethanol as substrates and amino modified molecular sieve SBA-15 as carrier, porcine pancreatic lipase was immobilized and the complex was used as catalyst to synthesize the esterification by reversible reaction. After separation and purification, the product was detected by IR and UV, and the yield of ethyl palmitate was calculated by acid value method. The optimum conditions for the synthesis of ethyl palmitate were determined by single factor experiment and response surface analysis. This paper mainly includes the following aspects: the first part: synthesis of NH2-SBA-15. Under acidic conditions, mesoporous molecular sieve SBA-15, was synthesized by hydrothermal method using triblock copolymer PEO20-PPO70-PEO20 (P123) as template and ethyl orthosilicate as silicon source. The residual template P123 was calcined at 550 鈩
本文编号：2337283
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