Determination of monosaturated fatty acid double-bond position and geometry for microbial monocultures and complex consortia by capillary GC-MS of their dimethyl disulphide adducts

Abstract

Monounsaturated fatty acid double-bond position and geometry have been determined for microbial monocultures and complex microbial consortia by capillary GC-MS of their dimethyl disulphide (DMDS) adducts. The technique has permitted ( i) chromatographic separation and positive identification of adducts derived from cis/trans isomers, ( ii) characterization of long-chain monounsaturated components (up to 26:1), and ( iii) the identification of a wide range of monounsaturated components derived from methanotrophic soil material. The methanotrophic soil sample contained a high relative proportion of the novel phospholipid ester-linked fatty acid 18:1Δ 10c. The DMDS procedure offers a simple and rapid approach that can be routinely applied to microbial fatty acids derived from environmental samples and monocultures.