Extraction Procedures and GCxGC-TOFMS Determination of Fatty Acids (FAs) in Cyanobacteria Cultures and the Effect of Growth Media Iron Concentration Variation on Cellular FAs Composition
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Date
2015-03
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Abstract
Cyanobacteria are a diverse group of photosynthetic organisms found mostly in freshwater bodies [1]. Cyanobacteria, apart from producing different useful metabolites for different applications such as pharmaceuticals, production of fine chemicals, biofertilizers and animal feed [2-5], they are known to produce lipophilic extractives such as fatty acids which are somewhat toxic to aquatic organisms, especisally unsaturated fatty acids. They are known to affect fish in freshwater bodies by interfering with the gill basolateral membrane ion-extrusion mechanisms leading to the death of fish [1,6]. Thus, the toxicity properties of fatty acids released by cyanobacteria in freshwater bodies to other aquatic organisms have increased the need to characterise the composition of fatty acids in cyanobacteria. Currently the production of biodiesel has increased the importance of lipids and hence the extraction techniques from different sources [7]. Moreover, fatty acids have been identified as essential components of the diet of humans and animals [8]. This fact has highly contributed to the interest of different researchers on the effective techniques to obtain fatty acids from cyanobacteria. Polyunsaturated fatty acids such as 9,12-Octadecadienoic acid (C18:2) and γ-6,9,12-octadecatrienoic acid (γ-C18:3) are known for their human health importance [1,9]. Furthermore, the analysis of long chain fatty acids has been so significant for biological and medical investigations [7]. The most prominent analytical instrument for fatty acids analysis is gas chromatography-mass spectrometry (GC-MS) [10]. However, due to the separation problem of fatty acids with similar chemical structures such as fatty acids with a chain of 18 carbon atoms, a more advanced gas chromatographic technique (GCxGC-TOFMS) has been employed in fatty acids and lipids analysis. GCxGC-TOFMS is a powerful analytical technique for the qualitative and quantitative determination of lipid composition. Fatty acids are currently best determined by GCxGC-TOFMS after derivatization to fatty acids methyl esters (FAMEs). The use of deconvolution algorithm of ChromaTOF software of GCxGC-TOFMS enables the separation of mass spectra and identification of FAMEs which some have a tendency of coeluting and bearing similar mass spectra due to their similar chemical structures. Extraction of fatty acids and lipids from the solid samples has generally been achieved by using volatile organic solvents under different extraction techniques reported in the literature. However, due to the nature of algae biomass, and the fact that they contain unusual lipid classes and fatty acids which differ from the ones in higher animals and plants [7], it is important to investigate a suitable extraction method for lipids and fatty acids from algae biomass. Among the techniques which are reported to be suitable, ultrasonic solid liquid extraction techniques has been found to be more effective as well as time effective [11]. Lipids and fatty acids in particular can be effectively extracted using polar organic solvents which are able to extract a larger range of organic compounds from biomass samples mostly at an elevated temperature [12].
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http://www.omicsonline.org/open-access/extraction-procedures-and-gcxgctofms-determination-of-fatty-acids-fasin-cyanobacteria-cultures-and-the-effect-of-growth-media-iron-concentrationvariation-on-cellular-fas-composition-2161-0525-S7-009.php?aid=58044
Keywords
Cyanobacteria, Iron concentration, Fatty acids, Gas Chromatography, Time-of-flight, Mass spectrometry, Ionic liquid
Citation
Kilulya, K.F., Mamba, B.B. and Msagati, T.A., 2015. Extraction Procedures and GCxGC-TOFMS Determination of Fatty Acids (FAs) in Cyanobacteria Cultures and the Effect of Growth Media Iron Concentration Variation on Cellular FAs Composition. Journal of Environmental & Analytical Toxicology, 2015.