Geobacter metallireducens
| Geobacter metallireducens | |
|---|---|
Scientific classification 
| |
| Domain: | Bacteria |
| Phylum: | Thermodesulfobacteriota |
| Class: | Desulfuromonadia |
| Order: | Geobacterales |
| Family: | Geobacteraceae |
| Genus: | Geobacter |
| Species: | G. metallireducens
|
| Binomial name | |
| Geobacter metallireducens Lovley et al. 1995
| |
Geobacter metallireducens is a
Geobacter metallireducens was discovered by Derek Lovley at UMass Amherst in 1993.[1] It is an iron-reducing bacteria and it has been thought that the microbe could be used to treat industrial sites where "cyanide-metal complexes" have formed to contaminate the site.[4]
The genome of Geobacter metallireducens has a
Geobacter metallireducens becomes motile when necessary, producing a flagellum in order to relocate when environmental conditions become unfavorable. [4] Insoluble Fe(II) and Mn (II) are electron acceptors for many chemolithotrophic microorganisms. Fe (II) is produced through the reduction of Fe(III) and Mn (IV) oxides. It is often difficult for these organisms to attain iron and manganese because Fe(III) and Mn (IV) oxides do not freely diffuse through bacterial membranes. Geobacter metallireducens has evolved a unique way to access iron via insoluble Fe(III) and Mn (IV) oxides; they grow motility appendages to help them find and contact the insoluble oxides. [7] According to a study conducted by Childers et. al., cells of G. metallireducens that grew in an environment with insoluble Fe(III) and Mn (IV) oxides grew flagella and pili. Whereas those grown in environments with soluble Fe(III) and Mn (IV) oxides did not have flagella nor pili. G. metallireducens is only motile when there are no soluble Fe(III) and Mn (IV) oxides in its environment to act as the electron acceptor. It is the first known microorganism to display chemotactic tendencies towards iron and manganese, as well as the first microbe discovered that oxidizes organic compounds with the inorganic elements iron and manganese. [7]
G. metallireducens does not solely reduce Fe(III) and Mn(IV) oxides, it can reduce a variety of compounds including those that are toxic or radioactive such as uranium, plutonium, technetium, and vanadium.[8] Vanadium, specifically, can contaminate groundwater in areas near high mining activity. G. metallireducens can utilize vanadium (V) as an energy source by reducing the metal to vanadium (IV). Therefore the bacteria can be used to aid in decontamination of affected groundwaters. G. metallireducens can use a similar mechanism to reduce uranium (VI) to uranium (V) in contaminated groundwaters. However, there is still research to be done on making this process more effective. [9]
G. metallireducens has been demonstrated to reduce chloramphenicol (CAP) to complete dechlorination products under pure culture conditions. Research utilizing cyclic voltammograms and chronoamperometry revealed that the bacteria exhibited a negative correlation CAP removal efficiency with initial CAP dosages, displaying the organism's potential application of bioremediation in environments polluted by antibiotics.[10]
G. metallireducens can make electrical connections with other microbes. This, in turn, allows other microbes to perform anaerobic syntrophic metabolism of organic substrates. This process of this electrical connection is called direct interspecies electron transfer (DIET). DIET is a metabolism that is defined by the movement of free electrons, rather than organisms only receiving electrons via the reduction of other compounds. [11] The pili of G. metallireducens conduct electrical currents. They can transfer electrons to other Geobacter species as well as archaea, specifically methanogens. The DIET connection to methanogens allows these bacteria to contribute to the methane cycle, and convert organic wastes to methane. [12]
See also
References
Further reading
- Eickhoff M, Birgel D, Talbot HM, Peckmann J, Kappler A (2013). "Bacteriohopanoid inventory of Geobacter sulfurreducens and Geobacter metallireducens". Organic Geochemistry. 58: 107–114. ISSN 0146-6380.
- Schleinitz KM, Schmeling S, Jehmlich N, von Bergen M, Harms H, Kleinsteuber S, Vogt C, Fuchs G (June 2009). "Phenol degradation in the strictly anaerobic iron-reducing bacterium Geobacter metallireducens GS-15". Applied and Environmental Microbiology. 75 (12): 3912–3919. PMID 19376902.
- Zhang T, Tremblay PL, Chaurasia AK, Smith JA, Bain TS, Lovley DR (22 May 2014). "Identification of genes specifically required for the anaerobic metabolism of benzene in Geobacter metallireducens". Frontiers in Microbiology. 5: 245. PMID 24904558.
