IDENTIFICATION OF SOME UNCOMMON MONOUNSATURATED FATTY-ACIDS OF BACTERIA

Location of the double-bond positiOn Of monounsaturated fatty acids of various bacteria was accomplished with combined gas chromatography-mass spectrometry analysis of dimethyl disulfide (DMDS) derivatives. The monoenoic fatty acids from whole cells were converted to methyl esters and then to DMDS adducts and analyzed by capillary gas chromatography-mass spectrometry. The mass spectra of DMDS adducts gave an easily recognizable molecular ion and two major diagnostic ions attributable to fragmentation between the two CH3S groups located at the original site of unsaturation. Twenty-one relatively novel monoenoic fatty acids were identified among the bacteria studied. All Flavobacterium species contained i17:1-omega-8c, Bacillus alvei contained i16:1-omega-11c and i17:l-omega-12c, and Psychrobacter immobilis contained 12:1-omega-9c. Resolution of cis and trans isomers with capillary gas chromatography and subsequent mass spectrometry permitted positive identification of 16:1-omega-7c and 16:1-omega-7t in Arcobacter (Campylobacter) cryaerophila and 16:1-omega-9c and 16:1-omega-9t in Aerococcus viridans.