Desulphurization of dibenzothiophene and diesel oils by bacteria.
OBJECTIVE
To study the desulphurization of dibenzothiophene (DBT), a recalcitrant thiophenic component of fossil fuels, by two bacteria namely Rhodococcus sp. and Arthrobacter sulfureus isolated from oil-contaminated soil/sludge in order to use them for reducing the sulphur content of diesel oil in compliance with environmental regulations.


RESULTS
The desulphurization pathway of DBT by the two bacteria was determined by gas chromatography (GC) and GC-mass spectrometry. Both organisms were found to produce 2-hydroxy biphenyl (2-HBP), the desulphurized product of DBT. Sulphur contents of culture supernatants of Rhodococcus sp. and A. sulfureus grown with DBT as sole sulphur source were analysed by X-ray fluorescence indicating sulphur levels of 8 and 10 ppm, respectively, as compared with 27 ppm in control. In order to study desulphurization of diesel oils obtained from an oil refinery, resting cell studies were carried out which showed a decrease of about 50% in sulphur content of the oil obtained from the hydrodesulphurization (HDS) unit of the refinery.


CONCLUSIONS
Rhodococcus sp. and A. sulfureus selectively remove sulphur from DBT to form 2-HBP. Application of these bacteria for desulphurization of diesel showed promising potential for decreasing the sulphur content of diesel oil.


CONCLUSIONS
The process of microbial desulphurization described herein can be used for significantly reducing the sulphur content of oil, particularly, after the process of HDS which would help in meeting the regulatory standards for sulphur level in diesel oil.
Labana
S
S
Institute of Microbial Technology, Chandigarh, India.
Pandey
G
G
Jain
R K
RK
D001173:Arthrobacter / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001713:Biphenyl Compounds / Q000032:analysis; D005648:Fuel Oils / Q000382:microbiology; D008401:Gas Chromatography-Mass Spectrometry; D005742:Gasoline / Q000382:microbiology; D012240:Rhodococcus / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism; D013455:Sulfur / Q000032:analysis / Q000378:metabolism*; D013876:Thiophenes / Q000378:metabolism*
D001713:Biphenyl Compounds; D005648:Fuel Oils; D005742:Gasoline; D012989:Soil Pollutants; D013876:Thiophenes; D013455:Sulfur; C004369:2-phenylphenol; C016366:dibenzothiophene