Method for extraction and separation by solid phase extraction of neutral lipid, free fatty acids, and polar lipid from mixed microbial cultures

A method using solvent extraction followed by selective elution from aminopropyl bonded phase columns has been developed for the separation of lipid classes in mixed microbial cultures. Lipid extraction in heptane/2-propanol (1:4 v/v) of culture solids (pelleted by centrifugation) was in excess of 95% of total lipid in cultures with no lipid in the liquid portion of the culture. Lipid classes were separated from extracts using modifications of an existing procedure using aminopropyl bonded phase columns. Single lipid classes were verified by thin layer chromatography with comparison to known standards. Quantification of fatty acids in individual fractions was by gas-liquid chromatography and resulted in excess of 95% recovery of fatty acids from a standard lipid mixture.