zahra zaimzadeh irani - iranian research institute of petroleum industry
mohammadreza mehrnia - school of chemical engineering
ghasemali mohebali - iranian research institute of petroleum industry
fatemeh yazdian - iranian research institute of petroleum industry

gas -oil reservoirs are contaminated with sulfur and presence of this component seriously inhibits the processing of gas -oil because of catalytic poisoning and corrosion. Moreover the direct combustion will release large amount of sulfur oxides that produce acid rains and poison the catalytic converters in automobile exhaust systems , so currently acceptable sulfur levels in fossil fuels are on the order of 10ppm. hydrodesulfurizaiton HDS is a high pressure and high-temperature process that uses hydrogen gas to reduce sulfur in petroleum fractions particularly diesel to hydrogen sulfide however; the HDS units are expensive to build and operate. in addition , it is not work well on polyaromatic sulfur heterocycles PASHs found in heavier fractions. biodesulfurization offers the potential technique for a more selective and cost effective method for lowering the sulfur content of petroleum products. the intensive research has been carried out to improve the biodesulfurization efficiency but more work is needed in areas such as bioreactor design product recovery and gas oil water separations.

biodesulfurization, technique, bioreactor, kinetic , separation.