Microbial metabolism of methanesulfonic acid

Methanesulfonic acid is a very stable strong acid and a key intermediate in the biogeochemical cycling of sulfur. It is formed in megatonne quantities in the atmosphere from the chemical oxidation of atmospheric dimethyl sulf ide (most of which is of biogenic origin) and deposited on the Earth in rai n and snow, and by dry deposition. Methanesulfonate is used by diverse aero bic bacteria as a source of sulfur for,growth, but is not known to be used by anaerobes either as a sulfur source, a fermentation substrate, an electr on acceptor, or as a methanogenic substrate. Some specialized methylotrophs (including Methylosulfonomonas, Marinosulfonomonas, and strains of Hyphomi crobium and Methylobacterium) can use it as a carbon and energy substrate t o support growth. Methanesulfonate oxidation is initiated by cleavage catal ysed by methanesulfonate monooxygenase, the properties and molecular biolog y of which are discussed.