Biodegradation of Dibenzothiophene Using Bacteria Isolated from Samboja Kutai, East Kalimantan: Indonesia

The objective of this research was to find out the potential of oil desulfurizing bacteria isolated from tropical soil contaminated with fossils oil. The bacteria were isolated by using medium of mineral salt sulfur-free (MSSF) supplemented with concentrated fraction of aromatic compounds as the sole sulfur source (MSSF-CA). Result of the research showed that 67 isolates of oil desulfurizing bacteria were isolated from soil in Samboja Kutai East Kalimantan, Indonesia. The isolates were candidate of bacteria which were capable to desulfurize polycyclic aromatic sulfur heterocycles (PASHs) in the model oil, n-tetradecane containing dibenzothiophene (DBT). A collection of 29 out of 67 isolates showed potential as oil desulfurizing bacteria and can grow on media of MSSF (water phase) containing DBT in n-tetradecane (oil phase) and the ratio of oil/water was 1:5. Some isolates could grow in the medium with OD660 ranged from 0.56 to 1.12 and could degrade DBT compounds in range of 26.34-81.88% and the maximum being degraded by Pseudomonas luteola SBJ4a after 72 h incubation at 37 degrees C with shaking of 150 rpm.