Changes in whole cell-derived fatty acids induced by benzene and occurrence of the unusual 16 : 1 omega 6c in Rhodococcus sp 33

We report for the first time the fatty acid composition, as measured by cap illary gas chromatography, of a Rhonococus sp. when grown in the presence a nd absence of benzene. The organism increased its ratio of saturated/unsatu rated fatty acids from 1.3 to 1.5 and 1.8 when grown on mannitol, benzene a nd mannitol+benzene, respectively. The observed increase in saturated fatty acids during growth in the presence of benzene is suggested as a possible mechanism 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 u nreported in Rhodococcus spp. (C) 1999 Federation of European Microbiologic al Societies. Published by Elsevier Science B.V. All rights reserved.