Evaluation of methods to extract and quantify lipids from Synechocystis PCC 6803.
In order to use the photosynthetic cyanobacterium Synechocystis as a source of feedstock for carbon-neutral, nonpetroleum-based diesel fuel, we evaluated several solvents and solvent systems for their ability to extract lipid from wild-type Synechocystis PCC 6803. Chloroform+methanol-based Folch and Bligh & Dyer methods had the highest lipid recoveries. Less toxic solvents, such as methanol and MTBE, or direct trans-esterification of biomass (without pre-extraction step) gave only slightly lower lipid-extraction yields. Ethanol, isopropanol, butanol, hexane, acetic ester, and their combinations were not effective for lipid extraction from Synechocystis (>20% loss), even though they are widely used for non-polar lipid extraction from other feedstock, including algae. We confirmed the success of chloroform+methanol-based extraction by their penetration of the cell membrane system, higher polarity, and stronger interaction with hydrogen bonds. The less-polar solvents not only had lower lipid yield, but also extracted more non-lipid compounds that require extra purification to remove. We also characterized the fatty-acid profile of Synechocystis PCC 6803: C16:0 (∼60%), C16:1 (∼9.5%), C18:0 (∼1.2%), C18:1 (∼2%), C18:2 (∼9.8%), and C18:3 (∼16.5%).
Sheng
Jie
J
Center for Environmental Biotechnology, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-5701, USA. Jie.Sheng@asu.edu
Vannela
Raveender
R
Rittmann
Bruce E
BE
D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D004075:Diglycerides / Q000032:analysis; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D008055:Lipids / Q000032:analysis* / Q000302:isolation & purification*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D046939:Synechocystis / Q000378:metabolism / Q000648:ultrastructure; D014280:Triglycerides / Q000032:analysis
D004075:Diglycerides; D004952:Esters; D005227:Fatty Acids; D008055:Lipids; D012997:Solvents; D014280:Triglycerides