【作者】 周位；

【导师】 闫云君；

【作者基本信息】 华中科技大学 ， 生物化工， 2007， 硕士

【摘要】 生物柴油作为一种对环境友好、无毒、可再生的替代燃料,已受到越来越多的关注。本文研究了复合脂肪酶催化制备生物柴油的新工艺,主要结果如下:从游离脂肪酶催化制备生物柴油的实验中发现多种酶混合催化制备生物柴油过程中存在协同现象,并利用多种游离脂肪酶对这一现象进行了验证,确认复合脂肪酶比单一脂肪酶对催化酯交换反应有更为显著的促进作用,复合脂肪酶能有效地克服单一脂肪酶催化的位置专一性,提高生物柴油的转酯效率,特别是在转酯能力相当而位置特异性不同的脂肪酶之间表现出更强的协同效应。进行了复合酶催化制备生物柴油工艺的初步研究,分别进行了无溶剂体系与叔丁醇体系中复合固定化脂肪酶与单一酶转酯效率的对比试验。在无溶剂体系中,Novozym435分别与Lipozyme TLIM和Lipozyme RMIM以70/30比例混合时,甲酯得率分别达到94.52%和96.25%,比Novozym435单独催化时的甲酯得率分别提高了9.52%和9.99%;在叔丁醇体系中,当Novozym435与Lipozyme TLIM和Lipozyme RMIM分别以60/40和80/20的比例混合时,其甲酯得率分别为85.06%和81.5%,比Novozym435单独催化的效率分别提高了9.89%和7.48%。两种体系均表现出较强的协同效果。通过对叔丁醇体系中Novozym435与Lipozyme TLIM复合酶催化条件进行优化表明:在溶剂添加量为40%、醇油摩尔比4:1、复合酶添加量为Novozym435 1.35%+Lipozyme TLIM 1.80%,温度为40℃,摇床转速为200rpm,反应24小时,甲酯得率达到92%,复合酶在该工艺下连续使用八次时甲酯得率仍保持在90%以上。进行了复合酶工艺扩大油源底物的研究,复合酶在叔丁醇体系中催化大豆油、菜籽油、棉籽油、蓖麻油、橄榄油、茶油、桐油的甲酯得率均在90%以上,均高于单一脂肪酶催化的甲酯得率。这表明复合酶工艺具有对广泛油源底物的适应性。因此,复合酶催化制备生物柴油工艺具有很大的潜在实用价值。更多还原

【Abstract】 Increasing attention is being paid to biodiesel as a friendly environmental, non-toxic and renewable diesel fuel. In this study, the biodiesel production with compound lipases has been investigated.Synergistic effect was found in biodiesel production catalyzed by free compound lipase, and was validated by a series of free lipases. The results showed that the transesterification efficiency of compound lipases in biodiesel production was higher than that of single lipase with high region-selectivity. This synergistic effect is especially obvious among lipases with the similiar transesterification efficiency yet different region-selectivity.The biodiesel production with compound immobilized lipases was investigated. The transesterification efficiencies between compound lipases and single lipase in solvent-free system and tert-butanol system were compared, and the compound lipases were found to have higher efficiency. And the ratios of lipases in the compound lipases were optimized.In solvent-free system, when Novozym435 was mixed with Lipozyme TLIM and Lipozyme RMIM both at the ratio of 70/30, the methyl ester yields were higher than that of only with Novozym435 by 9.52% and 9.99% respectively; while in tert-butanol system, when Novozym435 was mixed with Lipozyme TLIM and Lipozyme RMIM at the ratio of 60/40 and 80/20, the methyl ester yields were higher than that of only with Novozym435 by 9.89% and 7.48% respectively. Compound lipases exhibited synergistic effect in isolvent-free system and tert-butanol system.The reaction condition in tert-butanol system was optimized. The results showed when the optimal conditions for transesterification were 40% solvent quantity, temperature 40℃, 4:1methanol/oil molar ratio, Novozym435 1.35%+Lipozyme TLIM 1.80% lipase, 200rpm, methyl esters yield of 92% was obtained after 24h reaction, and the compound lipases were continuously used for 8 cycles, methyl esters yield were always over 90%, which suggested there was no obvious loss of their activity.Compound lipases were used to catalyze more oil substrates. The methyl ester yields was all higher than 90%, much higher than that of single lipase in soybean oil, rapseed oil, cottonseed oil, castor oil, olive oil, tea oil and tung oil. The results showed that compound lipases have great potentiality to apply for various oils to make biodiesel.更多还原