Microbial cycling of volatile organic sulfur compounds

Abstract

Microbial cycling of volatile organic sulfur compounds (VOSCs), especially dimethyl sulfide (DMS) and methanethiol (MT), is intensively studied because these compounds play an important role in the processes of global warming, acid precipitation, and the global sulfur cycle. VOSC concentrations in freshwater sediments are low due to the balance between the formation and degradation of these compounds. These reactions occur for the greater part at the oxic/anoxic interphase of sediment and water column. In contrast to marine ecosystems, where dimethylsulfoniopropionate is the main precursor of MT and DMS, in freshwater ecosystems, VOSCs are formed mainly by methylation of sulfide and to a lesser extent from the degradation of S-containing amino acids. One of the major routes for DMS and MT formation through sulfide methylation is anaerobic O-demethylation of methoxylated aromatic compounds. Inhibition studies have revealed that the major part of the endogenously produced MT and DMS is degraded anaerobically by methanogens. The major bacterial groups involved in formation and consumption of VOSCs are described.

The Cysteine Dioxygenase Homologue from Pseudomonas aeruginosa Is a 3-Mercaptopropionate Dioxygenase

“…Considering the relatively high concentrations of reactants used in this experiment, the possibility of 3-MPA autoxidation to 3-MPA disulfide was investigated. To this end, 1 H NMR spectra of room temperature buffered solutions of 3-MPA alone and 3-MPA disulfide produced with H 2 O 2 were measured. Using these spectra allowed estimation of 3-MPA disulfide levels in enzymatic mixtures, which represented less than 1%.…”

“…cysteine or hydrogen sulfide), 0 as elemental sulfur, and ϩ6 as sulfate. Within the sulfur cycle, microbiological transformation dominates the conversion of inorganic sulfur and to some extent organic sulfur (1). Whereas bacteria are very flexible in terms of their sulfur source, animals require dietary intake of sulfurcontaining amino acids, such as methionine, which serves as a biosynthetic precursor of cysteine (2).…”

Bacteria associated with iron seeps in a sulfur-rich, neutral pH, freshwater ecosystem

“…Dimethyl sulfide is an important volatile organic sulfur compound produced by algae, animals, microorganisms and plants by various mechanisms (Bentley and Chasteen, 2004). Volatile organic sulfur compounds, such as DMS, play an important role in the global sulfur cycle, in affecting the global climate and in acid precipitation (Lomans et al, 2002).…”

Glutathione Reductase/Glutathione Is Responsible for Cytotoxic Elemental Sulfur Tolerance via Polysulfide Shuttle in Fungi

“…Elemental sulfur is ubiquitous in the environment, and its reduction to sulfide is an essential step in the global sulfur cycle (5,6). Microorganisms are important players in this process.…”