Biodesulfurization of hydrocarbons and diesel fuels by Rhodococcus sp strain P32C1

The ability of Rhodococcus sp. P32C1 for desulfurization of n-hexadecane (n-C16) containing dibenzothiophene (DBT), and two different diesel oils is evaluated. Cells cultivated in the medium containing DBT of 0.1 mM showed higher desulfurization activity, and the effects of cell concentration on the desulfurization reaction were studied. Three hydrocarbon-aqueous phase ratios of 25, 50 and 75 vol.% were used for desulfurization of n-C16 containing 1 and 24 mM of DBT as a sulfur source. The maximum specific production rate of 2-hydroxybiphenyl (2-HBP) in two-phase system was 43.5 mmol/(kg dry cell.h). Based on the optimum conditions determined for desulfurization of n-C16, diesel oils with different sulfur contents were treated by resting cells. The total sulfur content of 303 ppm in the light diesel oil previously processed through hydrodesulfurization (HDS) was reduced by 48.5 wt.%. Another diesel oil with initial sulfur of 1000 ppm was desulfurized by 23.7 wt.%. (C) 2001 Elsevier Science B.V. All rights reserved.