ORGANIC SOLVENT RESISTANCE MECHANISMS IN RHODOCOCCUS sp. Po4

Crude oil extraction, transportation and storage facilities are frequently the source of soil and water pollution in Romania. Rhodococcus sp. Po4 showed good tolerance to both 1 % (v/v) alkanes (cyclohexane, nhexane, n-decane) and aromatics (toluene, styrene, ethylbenzene) with log POW (logarithm of the partition coefficient of the solvent in n-octanol-water mixture) values between 2.64 and 5.98. However, 1 % (v/v) alkanes were less toxic for Rhodococcus sp. Po4 cells, compared with 1 % (v/v) aromatics. The high organic solvent tolerance of Rhodococcus sp. Po4 could be due to the presence in their large genome of some catabolic and trehalose-6-phosphate synthase genes. In addition, Rhodococcus sp. Po4 exhibits potential to synthesize carotenoid pigments which can improve the cell membrane impermeability to toxic organic solvents.