Desulfonema limicola
Classification
Domain (Bacteria); Phylum (Progeobacteria); Class (Deltaprogeobacteria); Order (Desulfobacterales); Family (Desulfobacteraceae); Genus (Desulfonema)
Species
Desulfonema limicola
Description and Significance
Sulfate-reducing bacteria were first discovered in 1895 by Beijerinck. Since then, several species of sulfate-reducing bacteria have been described. Desulfonema limicola, which means thread-forming, sulfate reducer, mud-dweller, was described in 1983 by Widdel.
Desulfonema limicola is a filamentous, multicellular, prokaryote bacterium. Cells are approximately 2.3-3 by 2-5 µm. The species is a strict anaerobe that is found in organic-rich, sulfidic sediment samples of marine and freshwater. Optimum temperature and pH are 30C and 7.6, respectively. The morphology of Desulfonema limicola allows the bacterium to glide and migrate within compact sediments. This species is important because it mineralizes dead biomass in sulfate-rich anoxic habitats.
Genome Structure
The genome has yet to be sequenced, however, Gerard Muyze is in the process of doing so. [Gordon and Betty Moore Foundation. 2010]
Cell Structure, Metabolism and Life Cycle
Desulfonema limicola has cell walls characteristic of Gram-negative bacteria, a dense cytoplasm, and an outer membrane with a waved structure. Electron donors and carbon sources metabolized include low-molecular weight compounds from the fermentative breakdown of biomolecules, aromatic compounds, and hydrocarbons, including acetate, succinate, and fumarate. These compounds are oxidized to carbon dioxide. Sulfate is used as the organism as the electron acceptor and is reduced to hydrogen sulfide.
Ecology and Pathogenesis
Sulfate-reducing populations provide carbon dioxide within or near photosynthetically active microbial mats. Desulfonema limicola have biogeochemical significance because they reduce sulfate in organic sediments and microbial mats.
References
Author
Page authored by Megan Andrzejak and Laura Bast, student of Prof. Jay Lennon at Michigan State University.
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