Metabolism of reduced methylated sulfur compounds in anaerobic sediments and by a pure culture of an estuarine methanogen

Applied and Environmental Microbiology
By: , and 

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Abstract

Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity of anoxic aquatic sediments (e.g., fresh water, estuarine, alkaline/hypersaline) stimulated methane production. The yield of methane recovered from DMS was often 52 to 63%, although high concentrations of DMS (as well as MSH and DMDS) inhibited methanogenesis in some types of sediments. Production of methane from these reduced methylated sulfur compounds was blocked by 2-bromoethanesulfonic acid. Sulfate did not influence the metabolism of millimolar levels of DMS, DMDS, or MSH added to sediments. However, when DMS was added at ∼2-μM levels as [14C]DMS, metabolism by sediments resulted in a 14CH4/14CO2 ratio of only 0.06. Addition of molybdate increased the ratio to 1.8, while 2-bromoethanesulfonic acid decreased it to 0, but did not block 14CO2 production. These results indicate the methanogens and sulfate reducers compete for DMS when it is present at low concentrations; however, at high concentrations, DMS is a “noncompetitive” substrate for methanogens. Metabolism of DMS by sediments resulted in the appearance of MSH as a transient intermediate. A pure culture of an obligately methylotrophic estuarine methanogen was isolated which was capable of growth on DMS. Metabolism of DMS by the culture also resulted in the transient appearance of MSH, but the organism could grow on neither MSH nor DMDS. The culture metabolized [14C]-DMS to yield a 14CH4/14CO2 ratio of ∼2.8. Reduced methylated sulfur compounds represent a new class of substrates for methanogens and may be potential precursors of methane in a variety of aquatic habitats.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Metabolism of reduced methylated sulfur compounds in anaerobic sediments and by a pure culture of an estuarine methanogen
Series title Applied and Environmental Microbiology
Volume 52
Issue 5
Year Published 1986
Language English
Publisher American Society for Microbiology
Publisher location Washington, D.C.
Description 9 p.
First page 1037
Last page 1045
Country United States
State California
County San Francisco
City San fancisco
Other Geospatial San Francisco Bay area
Online Only (Y/N) N
Additional Online Files (Y/N) N