DESULFURIZATION OF PETROLEUM BY THE USE O F BIOTECHNOLOGY

Petroleum contains various kinds of heterocyclic organosulfur compound s refractory to conventional hydrodesulfurization. Several mesophilic and thermophilic bacteria, which are capable of cleaving efficiently c arbon-sulfur bonds in dibenzothiophene as a model compound, have been isolated, When these desulfurizing bacteria were used for treatment of light gas oil previously processed through hydrodesulfurization, the refractory organosulfur compounds in the oil phase clearly decreased. Moreover, the thermophilic desulfurizing bacteria was found to be able to release sulfur atoms as sulfate ion and leave the monohydroxylated hydrocarbon moieties intact on attacking dibenzothiophene and its var ious methylated derivatives at temperatures up to 60 degrees C.