Selection of Direct Transesterification as the Preferred Method for Assay of Fatty Acid Content of Microalgae
Selection of Direct Transesterification as the Preferred Method for Assay of Fatty Acid Content of Microalgae
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DOI：
10.1007/s11745-010-3468-2
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发表时间：
2010-11-01
期刊：
影响因子：
1.9
通讯作者：
Harrison, S. T. L.
中科院分区：
文献类型：
--
作者：
Griffiths, M. J.;van Hille, R. P.;Harrison, S. T. L.
微藻中总脂质含量的测定通常基于 Folch 或 Bligh 和 Dyer 溶剂提取方法，然后通过重量分析或色谱法进行定量。直接酯交换（DT）是一种将可皂化脂质直接原位转化为脂肪酸甲酯的方法，脂肪酸甲酯可以通过气相色谱（GC）进行定量。这消除了提取步骤，并导致适用于小样品的快速、一步式程序。本研究比较了 DT 定量三种微藻中总脂肪酸含量的有效性，以及使用 Folch、Bligh 和 Dyer 以及 Smedes 和 Askland 方法进行提取，然后进行酯交换和 GC 的效果。研究了两种催化剂的依次使用以及反应水含量对DT效率的影响。 Folch方法是所测试的提取方法中最有效的，但与DT的比较表明所有提取方法都是不完整的。与提取-酯交换方法相比，DT 获得了细胞中更高水平的脂肪酸。当样品含水时，酸性和碱性酯交换催化剂的组合比单独使用更有效。双催化剂反应对占总反应体积 10% 的水不敏感。 DT 被证明是一种比提取技术更方便、更准确的定量微藻中总脂肪酸含量的方法。
Assays for total lipid content in microalgae are usually based on the Folch or the Bligh and Dyer methods of solvent extraction followed by quantification either gravimetrically or by chromatography. Direct transesterification (DT) is a method of converting saponifiable lipids in situ directly to fatty acid methyl esters which can be quantified by gas chromatography (GC). This eliminates the extraction step and results in a rapid, one-step procedure applicable to small samples. This study compared the effectiveness of DT in quantifying the total fatty acid content in three species of microalgae to extraction using the Folch, the Bligh and Dyer and the Smedes and Askland methods, followed by transesterification and GC. The use of two catalysts in sequence, as well as the effect of reaction water content on the efficiency of DT were investigated. The Folch method was the most effective of the extraction methods tested, but comparison with DT illustrated that all extraction methods were incomplete. Higher levels of fatty acid in the cells were obtained with DT in comparison with the extraction-transesterification methods. A combination of acidic and basic transesterification catalysts was more effective than each individually when the sample contained water. The two-catalyst reaction was insensitive to water up to 10% of total reaction volume. DT proved a convenient and more accurate method than the extraction techniques for quantifying total fatty acid content in microalgae.