Pilot-scale supercritical carbon dioxide extractions for the recovery of triacylglycerols from microalgae: a practical tool for algal biofuels research

Autor: Karen M. MacDougall, William J. Bjornsson, Patrick J. McGinn, Jeremy E. Melanson, Stephen J. B. O’Leary
Rok vydání: 2011
Předmět:
Zdroj: Journal of Applied Phycology. 24:547-555
ISSN: 1573-5176
0921-8971
Popis: We describe the preliminary extractions from a pilot-scale supercritical carbon dioxide (SC-CO2) extractor for the isolation of algal lipids suitable for small-scale conversion to liquid hydrocarbon fuels. Flowable oils were recovered from SC-CO2 extractions of lyophilized Nannochloropsis granulata. The extracted oils were determined to be composed primarily of triacylglycerols (TAG) by liquid chromatography-mass spectrometry analysis. Gravimetric lipid yield was increased significantly from 15.56 to 28.45 mg g-1 ash-free dry weight (AFDW) with an increase in temperature from 50°C to 70°C, at 35 MPa over 270 min. Varying pressure had no significant effect on lipid yield. Liquid chromatography-mass spectrometry analysis of the SC-SO2 extracts indicated that the TAG profile remained constant regardless of extraction pressure, and analysis of fatty acid methyl esters (FAME) revealed a uniform profile throughout all extraction conditions. Our optimized gravimetric lipid yields from N. granulata (28.45 mg g-1 AFDW) were approximately half of the yields obtained by Soxhlet extraction with hexane (57.53 mg g-1 AFDW); however, the FAME yields were similar regardless of extraction technique (18.23 mg FAME g-1 and 17.35 mg FAME g-1 AFDW from SC-CO2 extraction and hexane extraction, respectively). Further extractions with Botryococcus braunii indicated that fatty acid extraction by SC-CO2 was as efficient as hexane extraction. These results highlight the suitability of SC-CO2 for large-scale oil extraction of microalgae for biofuel or biojet analyses due to its selectivity for TAG extraction.
Databáze: OpenAIRE
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