【作者】 孙燕；

【导师】 吾满江·艾力； 贾殿赠；

【作者基本信息】 新疆大学 ， 物理化学， 2006， 硕士

【摘要】 非水相酶学作为酶催化的一个新兴领域发展至今不足20年,但随着酶在非水介质中的结构特点、催化条件和催化机理的研究不断深入和系统,非水酶学的研究和发展前景变的越来越广阔,本文分别研究了在非水介质中催化合成L-抗坏血酸棕榈酸酯和亚麻酸甘油酯。第一部分研究以黑曲霉脂肪酶为催化剂,叔丁醇为溶剂,用酯交换法合成L-抗坏血酸棕榈酸酯(L-ascorbyl palmitate,L-AP),催化体系的最佳反应条件为:反应温度为36℃,摇床速度200r/min,反应时间为24h,底物棕榈酸甲酯与L-抗坏血酸的摩尔比为1.3:1.0,含水量为1%时,L-抗坏血酸的转化率为23%。第二部分研究以脂肪酶Novo435为催化剂,无溶剂体系中直接酯化合成亚麻酸甘油酯,此体系最佳反应条件为:反应温度为60℃,摇床转速为200r/min,甘油和亚麻酸以2:1(摩尔比),酶用量为1%(占亚麻酸的质量),缓冲液PH为7.0时,在开放体系中反应,底物亚麻酸的转化率可达90%以上。第三部分研究了以脂肪酶Novo435为催化剂,亚麻酸和甘油为原料,在有机溶剂中采用直接酯化法合成亚麻酸甘油酯,体系最佳反应条件为:正己烷为溶剂、温度60℃、醇酸摩尔比2.5:1、酶用量为1%(占亚麻酸的质量),反应24h,亚麻酸转化率为90%以上。对比无溶剂体系中及有机溶剂体系中的酯化反应,发现亚麻酸的转化率相近,但所得亚麻酸甘油酯的组成有显著差别,前者以三甘酯为主产物,后者以单甘酯和二甘酯为主产物。此研究对于利用酶催化反应得到高含量的目标产品有指导意义,为酶催化反应在工业化中的应用奠定了基础。更多还原

【Abstract】 Over the past decade,non-aqueous enzymology has emerged as a major area of research and development in biotechnology.In order to exploit non-aqueous enzymology fully,the work studied the various factors which affect the conversion of reactant of ester synthesis reaction in non-aqueous solvents. The main contents are as follows:1. With aspergillus niger as catalyst,preferred conditions for synthesis of L-ascorbyl palmitate from methyl palmitate and L-ascorbic acid were studied in detail. Results show that, when methyl palmitate and L-ascorbic acid was mixed at the molar ratio of 1.3:1.0, with dosage of 15% methyl palmitate as catalyst, under 36℃, under reaction for 24h,L-ascorbyl palmitate was obtained with a yield of 23%.2. The enzymatic esterifications of glycerol with linolenic acid were carried out efficiently using Novozym 435 in solvent-free system. When glycerol reacted with linolenic acid at 60℃, with a molar ratio of 2:1, catalyzed by 1% weight of lipase to linolenic acid, the maximum conversion of linolenic acid received 90%.3. The enzymatic esterifications of glycerol with linolenic acid were carried out efficiently using Novozym 435 in organic solvent system. When glycerol reacted with linolenic acid at 60℃, with a molar ratio of 2.5:1, the maximum conversion of linolenic acid received 90%.The conversion of linolenic acid had no difference in free-solvent and organic solvent,but the products were different in two systems.For the former, triacylglycerol was the primary product ; for the latter,however,mono- and diacylglycerol were the primary products.更多还原