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sunny5368101银虫 (正式写手)
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[求助]一段英文翻译 生物柴油方面的 （赠30金币） 已关帖
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Enzymatic transesterification of soybean oil with methanol and ethanol was studied. Of the nine lipases that were tested in the initial screening, lipase PS from Pseudomonas cepacia resulted in the highest yield of alkyl esters. Lipase from Pseudomonas cepacia was further investigated in immobilized form within a chemically inert, hydrophobic sol–gel support. The gel-entrapped lipase was prepared by polycondensation of hydrolyzed tetramethoxysilane and iso-butyltrimethoxysilane. Using the immobilized lipase PS, the effects of water and alcohol concentration, enzyme loading, enzyme thermal stability, and temperature in the transesterification reaction were investigated. The optimal conditions for processing 10g of soybean oil were: 35C, 1:7.5 oil/methanol molar ratio, 0.5g water and 475mg lipase for the reactions with methanol, and 35C, 1:15.2 oil/ethanol molar ratio, 0.3g water, 475mg lipase for the reactions with ethanol. Subject to the optimal conditions, methyl and ethyl esters formation of 67 and 65mol% in 1h of reaction were obtained for the immobilized enzyme reactions. Upon the reaction with the immobilized lipase, the triglycerides reached negligible levels after the first 30min of the reaction and the immobilized lipase was consistently more active than the free enzyme. The immobilized lipase also proved to be stable and lost little activity when was subjected to repeated uses. [ Last edited by sunny5368101 on 2007-7-2 at 09:59 ] |
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7楼2007-07-04 10:46:53
sunny5368101
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2楼2007-06-29 16:38:11
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在甲醇和乙醇的存在下, 用九种酯化酶对大豆油的酯化进行研究.从单假细胞菌分离出来的酶PS对烷基酯化反应有很高的收率.该酶在固定形态下, 进一步了研究了化学钝化,不溶于水的溶胶-凝胶体系的情况.采用固定形态的酶PS, 水解四甲基硅氧烷和异丁基三甲基硅氧缩聚制备凝胶获取的酶.水和醇的浓度,装载方式,酶热稳定性,酯化反应温度的效应,在酶的酯化反应被研究.最佳处理10克大豆油的条件是:35度,1:7.5油醇摩尔比.0.5克水和475毫克跟甲醇反应的酶,以及35度,1:7.5油甲醇莫尔比; 0.3克水和475毫克跟乙醇反应的酶,以及35度,1:15.2油乙醇摩尔比.根据最佳条件,经过一小时的反应,甲基和乙基的酯化收率分别达到67和65百分摩尔.对于固定形态酶的反应,在反应30分钟后,甘油磷酸酯几乎可以忽略而且固定形态酶比自由酶更有活性.在重复使用方面,固定形态的酶被证明比自由酶更有活性和稳定性. 初步翻译了下,看看能否有用  |
5楼2007-06-30 18:55:56
6楼2007-07-01 20:22:46