Cellular fatty acids are analysed after conversion into fatty acid methyl esters (FAMEs) by saponification, methylation and extraction using minor modifications of the method of Miller (1982) and Kuykendall et al., (1988). The fatty acid methyl esters mixtures are separated by gas chromatography and detected by a flame ionisation detector using Sherlock Microbial Identification System (MIS) (MIDI, Microbial ID, Newark, DE 19711 U.S.A.). Peaks are automatically integrated and fatty acid names and percentages calculated by the MIS Standard Software (Microbial ID).
In subsequent analysis, summed features are resolved and identities of fatty acids are confirmed by a GC-MS-based analysis using retention time locking and mass spectral data. Further derivatization procedures for structural elucidation of yet unidentified compounds can be performed upon request.
Required material: For the analysis of the cellular fatty acids an active growing culture or 30 mg freeze dried cells is required.
- Kuykendall, L.D., Roy, M.A., O'Neill, J.J., Devine, T.E. 1988. Fatty acids, antibiotic resistance, and deoxyribonucleic acid homology groups of Bradyrhizobium japonicum. International Journal of Systematic Bacteriology 38:358-361.
- Miller, L.T. 1982. A single derivatization method for bacterial fatty acid methyl esters including hydroxy acids. Journal of Clinical Microbiology 16:584-586.