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A comparative study: the impact of different lipid extraction methods on current microalgal lipid research.

Li Y, Ghasemi Naghdi F, Garg S, Adarme-Vega TC, Thurecht KJ, Ghafor WA, Tannock S, Schenk PM - Microb. Cell Fact. (2014)

Bottom Line: Among these extractions, significant differences were observed in both, extract yield and fatty acid composition.The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids.The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Agriculture and Food Sciences, The University of Queensland, Brisbane QLD 4072, Australia. yan.li3@jcu.edu.au.

ABSTRACT
Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO₂ extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research.

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Total amount of saturated, mono- and polysaturated fatty acids in microalgal dry biomass (%) across different extraction methods. Chl:Met -- chloroform and methanol method; Dic:Met -- dichloromethane and methanol method; Pro:Hex -- propan-2-ol and cyclohexane method; Eth:KOH -- ethanol and KOH method; ScCO2 -- supercritical-CO2 extraction method. Different symbols, small and capital letters represent significant differences on saturated, mono- and polysaturated fatty acids, respectively, for the different extraction methods (P < 0.05).
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Figure 2: Total amount of saturated, mono- and polysaturated fatty acids in microalgal dry biomass (%) across different extraction methods. Chl:Met -- chloroform and methanol method; Dic:Met -- dichloromethane and methanol method; Pro:Hex -- propan-2-ol and cyclohexane method; Eth:KOH -- ethanol and KOH method; ScCO2 -- supercritical-CO2 extraction method. Different symbols, small and capital letters represent significant differences on saturated, mono- and polysaturated fatty acids, respectively, for the different extraction methods (P < 0.05).

Mentions: The saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and PUFA were all obtained in five extraction methods from Tetraselmis sp. M8 biomass, but with different yields (P < 0.05, Figure 2). A significant difference was only observed between ScCO2 and Eth:KOH, where the FA yields were much lower in the latter (P < 0.05, Figure 2). Given the lower FA yields, Eth:KOH clearly shows a lack of competence for FA extraction. However, this is could be specific to Tetraselmis sp. M8, since direct saponification was quite successful for the lipid yield and better than liquid solvent extractions for other microalga species, such as Thraustochytrium sp. [7], Isochrysis galbana[21] and Phaeodactylum tricornutum[14]. On the other hand, it demonstrates the importance of testing different extraction methods for different microalgae.


A comparative study: the impact of different lipid extraction methods on current microalgal lipid research.

Li Y, Ghasemi Naghdi F, Garg S, Adarme-Vega TC, Thurecht KJ, Ghafor WA, Tannock S, Schenk PM - Microb. Cell Fact. (2014)

Total amount of saturated, mono- and polysaturated fatty acids in microalgal dry biomass (%) across different extraction methods. Chl:Met -- chloroform and methanol method; Dic:Met -- dichloromethane and methanol method; Pro:Hex -- propan-2-ol and cyclohexane method; Eth:KOH -- ethanol and KOH method; ScCO2 -- supercritical-CO2 extraction method. Different symbols, small and capital letters represent significant differences on saturated, mono- and polysaturated fatty acids, respectively, for the different extraction methods (P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3926349&req=5

Figure 2: Total amount of saturated, mono- and polysaturated fatty acids in microalgal dry biomass (%) across different extraction methods. Chl:Met -- chloroform and methanol method; Dic:Met -- dichloromethane and methanol method; Pro:Hex -- propan-2-ol and cyclohexane method; Eth:KOH -- ethanol and KOH method; ScCO2 -- supercritical-CO2 extraction method. Different symbols, small and capital letters represent significant differences on saturated, mono- and polysaturated fatty acids, respectively, for the different extraction methods (P < 0.05).
Mentions: The saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and PUFA were all obtained in five extraction methods from Tetraselmis sp. M8 biomass, but with different yields (P < 0.05, Figure 2). A significant difference was only observed between ScCO2 and Eth:KOH, where the FA yields were much lower in the latter (P < 0.05, Figure 2). Given the lower FA yields, Eth:KOH clearly shows a lack of competence for FA extraction. However, this is could be specific to Tetraselmis sp. M8, since direct saponification was quite successful for the lipid yield and better than liquid solvent extractions for other microalga species, such as Thraustochytrium sp. [7], Isochrysis galbana[21] and Phaeodactylum tricornutum[14]. On the other hand, it demonstrates the importance of testing different extraction methods for different microalgae.

Bottom Line: Among these extractions, significant differences were observed in both, extract yield and fatty acid composition.The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids.The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Agriculture and Food Sciences, The University of Queensland, Brisbane QLD 4072, Australia. yan.li3@jcu.edu.au.

ABSTRACT
Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO₂ extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research.

Show MeSH
Related in: MedlinePlus