Microbial desulfurization of dibenzothiophene

Concerning the sulfur removal from coal before combustion there is considerable interest in microbial methods as pyrite oxidation and elimination of organically bound sulfur from coal. Using organic sulfur compounds relevant for coal the mechanism of desulfurization was investigated. The authors isolated a defined mixed culture (FODO) able to utilize dibenzothiophene as sole sulfur source for growth, while benzoate was used as carbon source. The mixed culture FODO consists of an Alcaligenes denitrificans subspecies and a Brevibacterium species. Two metabolites of the degradation and dibenzothiophene-5-dioxide. The subsequent degradation of dibenzothiophene-5-dioxide used as sole sulfur source results in a release of sulfate ions into the medium. The results suggest a sulfur specific oxidative mechanism for removal of sulfur from dibenzothiophene.