The family Selenastraceae includes many species of freshwater green microalgae with morphological characteristics that are so subtly different that it is difficult to discriminate species within it. Therefore, the use of the diacritical characteristics of traditional morphological taxonomy may be ineffective at differentiating among many species of the family. Chemotaxonomy based on fatty acid methyl ester (FAME) can help resolve uncertainties not completely addressed by other approaches, such as molecular studies of some species within the Selenastraceae. Here, we first tested three techniques for the analysis of microalgal FAME to choose the one that would provide the best profiles for chemotaxonomy: 1) direct transesterification (DT) of the biomass followed by gas chromatography coupled to mass spectrometry analysis (GC-MS); 2) extraction using chloroform and methanol, followed by transesterification (T) and then analysis by gas chromatography/flame ionization detector (GC-FID); and 3) extraction with chloroform and methanol and then separation into lipid classes using thin-layer chromatography (TLC) using the Iatroscan-Chromarod system. The tests were conducted on 12 strains (11 species) of Selenastraceae and one outgroup strain. The fatty acid profiles produced by the DT-GC-MS technique yielded the best results for the chemotaxonomy of the Selenastraceae species using 12 FAME. The proportion of the variance in the fatty acid profiles obtained with DT-GC-MS analysis explained by species was 85%, whereas the differences explained by strains was 92%. Therefore, DT-GC-MS was used to analyze other microalgae strains, totaling 15 species of 8 genera of green coccoid microalgae, including the recently described Curvastrum. The results with all strains showed that fatty acid profiles obtained by DT-GC-MS were significantly different (p < 0.001) among strains and among species. The variance in fatty acids profiles explained by separation into strains was 97%, whereas the separation into species explained 93% of the variance. Statistical analyses showed that, for our dataset, the C₁₈ fatty acids 18:3ω3 and 18:4ω6 were indicative of the Selenastraceae. Therefore, fatty acid profiles are a useful auxiliary chemotaxonomic tool for species identification in Selenastraceae.

Selenastraceae科包括许多淡水绿色微藻物种，它们的形态特征微妙地不同，以致于很难区分其中的物种。因此，使用传统形态分类学的变音符号可能无法有效区分该家族的许多物种。基于脂肪酸甲酯（FAME）的化学分类法可以帮助解决其他方法无法完全解决的不确定性，例如对硒草科中某些物种的分子研究。在这里，我们首先测试了三种分析微藻FAME的技术，以选择能够提供最佳化学分类特征的技术：1）生物质的直接酯交换（DT），然后进行气相色谱-质谱分析（GC-MS） ; 2）用氯仿和甲醇萃取，然后进行酯交换（T），然后用气相色谱/火焰电离检测器（GC-FID）分析。3）用氯仿和甲醇萃取，然后使用Iatroscan-Chromarod系统通过薄层色谱（TLC）分离为脂质类。该测试是针对十二生菜科的12个菌株（11种）和一组外菌株进行的。通过DT-GC-MS技术产生的脂肪酸谱使用12 FAME获得了硒草科的化学分类的最佳结果。用物种进行的DT-GC-MS分析所获得的脂肪酸谱差异的比例为85％，而菌株所解释的差异为92％。因此，DT-GC-MS用于分析其他微藻菌株，弯曲。所有菌株的结果表明，通过DT-GC-MS获得的脂肪酸谱在菌株之间和物种之间显着不同（p <0.001）。分离成菌株所解释的脂肪酸谱变异为97％，而分离成种则解释了93％的变异。统计分析表明，就我们的数据集而言，C ₁₈脂肪酸18：3ω3和18：4ω6表示硒草科。因此，脂肪酸谱是用于鉴定硒草科中物种的有用辅助化学分类学工具。