Rapid extraction of lipid biomarkers from pure culture and environmental samples using pressurized accelerated hot solvent extraction

Lipid biomarker analysis is a quantitative and sensitive method for the in situ analysis of microbial communities in environmental samples (e.g. soil, water, air). The one-phase modified Bligh and Dyer solvent extraction is a commonly used method for obtaining phospholipid fatty acid biomarkers used in such community analysis. This method, however, is relatively labor intensive and slow, often taking up to 24 h for the initial extraction. Using a pressurized hot solvent extractor, we have been able to extract lipid biomarkers from selected vegetative and/or sporulated biomass (Escherichia coli, Staphylococcus aureus, Mycobacterium fortuitum, Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus niger) as well as from environmental samples collected from water, soil and air. Depending on sample type, the automated extraction procedure took similar to 35-45 min per sample. Compared to the modified Bligh and Dyer extraction, phospholipid fatty acid lipid yields obtained using the pressurized hot solvent extraction were not significantly different for the vegetative biomass or water and soil samples (P>0.05), but were significantly higher for the spores and the airborne biomass (P<0.05 for both sample types). The advantage of using accelerated hot solvent extraction is that by increasing the speed and decreasing the labor involved, pressurized hot solvent extraction should enable the rapid and improved extraction of lipids from large numbers of environmental samples providing data essential for total microbial community analysis. (C) 1997 Elsevier Science B.V.