Sulfur is important in the biosphere where it is part of the sulfur cycle. Sulfur is incorporated into cellular molecules such as biotin, lipoic acid and proteins (reviewed by Kessler, 2006). Sulfuric acid is a major industrial chemical. Commercial organosulfur compounds include dimethylsulfoxide, saccharin, and the dye mordant yellow 3. Sulfur-oxidizing prokaryotes can use sulfide, elemental sulfur, or thiosulfate as sources of energy and electrons for growth (reviewed by Friedrich et al., 2005). Sulfur-reducing prokaryotes use sulfate as an electron acceptor during anaerobic respiration, reducing sulfate to sulfide (reviewed by Hansen, 1994).

Organisms assimilate sulfur as sulfate. However, most of the sulfur in aerobic terrestrial environments occurs in organic form as sulfonates and sulfate esters, which may be natural products or anthropogenic compounds (reviewed by Kertesz, 2000). Desulfurization of organosulfur compounds by microorganisms is an important part of the global sulfur cycle. Sulfur can be liberated as sulfite from sulfonates via an oxygenase mechanism and as sulfate from sulfate esters by a hydrolytic mechanism (Kertesz, 2000). Biological desulfurization of sulfides, such as those present as impurities in fossil fuels (reviewed by Gupta et al., 2005), can occur under aerobic or anaerobic conditions.

For more information:

Search Medline for sulfur metabolism AND bacteria

Kirkwood KM, Ebert S, Foght JM, Fedorak PM, Gray MR. Bacterial biodegradation of aliphatic sulfides under aerobic carbon- or sulfur-limited growth conditions. J Appl Microbiol. 2005;99(6):1444-54.

Kletzin A, Urich T, Muller F, Bandeiras TM, Gomes CM. Dissimilatory oxidation and reduction of elemental sulfur in thermophilic archaea. J Bioenerg Biomembr. 2004 Feb;36(1):77-91.

Lomans BP, van der Drift C, Pol A, Op den Camp HJ. Microbial cycling of volatile organic sulfur compounds. Cell Mol Life Sci. 2002 Apr;59(4):575-88.

Malik A, Dastidar MG, Roychoudhury PK. Biodesulphurization of coal: mechanism and rate limiting factors. Environ Sci Health Part A Tox Hazard Subst Environ Eng. 2001;36(6):1113-28.