Isolation of a Dibenzothiophene Desulfurizing Bacterium from Soil of Tabriz Oil Refinery

Document Type : Brief Report


1 Biotechnology Center of Iranian Research Organization for Science and Technology, No.71, Forsat St., Enghelab Ave., Tehran, Iran.

2 Biology Department, Faculty of Science, Shahid Beheshti University, Evin, Tehran, Iran.


A dibenzothiophene (DBT) degrading bacterium, which utilizes DBT as the sole source of sulfur, was isolated from soil contaminated with crud oil collected from oil refinery of Tabriz (Iran). A convenient spectrophotometric assay (Gibbs’ assay) was used to determine the quantity of desulfurized product
(Hydroxybiphenyl). This isolate did not grow on DBT, dibenzothiophene sulfone (DBTO2), or 2-Hydroxybiphenyl (HBP) as sole carbon sources. Biodesulfurization activity was observed only in growing
cultures and depressed by free sulfate. The desulfurization trait was expressed at increasing levels during the exponential phase of growth and then declined in stationary-phase cells. This gram-positive, non-spore-forming, partially acid fast, polymorphic bacterium with the ability to desulfurize DBT or DBTO2 was identified as Rhodococcus sp. and designated strain FMF.