Bacterial Metabolism of C1 Sulfur Compounds

Abstract

The metabolism of C1 organosulfur compounds by the Bacteria is important in the biogeochemical cycling of sulfur and carbon, and in climate regulation in terms of mediating release of e.g. dimethylsulfide from the oceans. Herein we review the canon of work on the metabolism of dimethysulfide, dimethylsulfoxide, dimethylsulfone, methanesulfonate, dimethyldisulfide and methanethiol, in terms of dissimilation to formaldehyde or carbon dioxide when used as carbon and energy sources by methylotrophs or autotrophs; oxidation to sulfite prior to assimilation as sulfur sources, and use as respiratory terminal electron acceptors. We discuss the enzymology of the metabolism of these compounds and propose a revision to the Enzyme Commission classification to some of them where multiple enzymes are clearly grouped under one name at present. We also provide methodologies for enzyme assays, for the safe handling and quantification of these compounds, and for the synthesis of carbon-14, carbon-11, sulfur-34 and sulfur-34 compounds for use in physiological and ecological studies.