Changes in whole-cell derived fatty acids induced by benzene and occurrence of the unusual 16:1ω6c in Rhodococcus sp. 33

We report for the first time the fatty acid composition, as measured by capillary gas chromatography, of a Rhonococus sp. when grown in the presence and absence of benzene. The organism increased its ratio of saturated/unsaturated fatty acids from 1.3 to 1.5 and 1.8 when grown on mannitol, benzene and mannitol+benzene, respectively. The observed increase in saturated fatty acids during growth in the presence of benzene is suggested as a possiblemechanism to decrease the fluidity of the cell membrane to tolerate benzene. The organism was found to synthesize hexadecenoic acid, 16:1 omega 6c (11-13% of total fatty acids). This is an uncommon fatty acid and previously unreported in Rhodococcus spp.