Geothrix fermentans
| Geothrix fermentans | |
|---|---|
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Acidobacteria |
| Class: | Holophagae |
| Order: | Holophagales |
| Family: | Holophagaceae |
| Genus: | Geothrix |
| Species: | G. fermentans |
| Binomial name | |
|
Geothrix fermentans John D. Coates et al (1999) |
|
Geothrix fermentans is a rod-shaped, anaerobic bacterium. It is about 0.1 µm in diameter and ranges from 2-3 µm in length. Cell arrangement occurs singly and in chains. Geothrix fermentans can normally be found in aquatic sediments such as in aquifers. As an anaerobic chemoorganotroph, this organism is best known for its ability to use electron acceptors Fe(III), as well as other high potential metals. It also uses a wide range of substrates as electron donors. Research on metal reduction by G. fermentans has contributed to understanding more about the geochemical cycling of metals in the environment.
Geothrix fermentans was isolated from metal-contaminated waters of an aquifer in 1999 by John D. Coates from Southern Illinois University and by others from the University of Massachusetts. The novel strain was originally named "Strain H-5T ". After classifying metabolism and confirming the presence and number of c-type cytochromes, Coates et al. proposed that the novel organism belongs to the newly recognized (1991) Halophoga-Acidobacterium phylum. Coates et al. also proposed a new name for the organism: "Geothrix"- Greek for hair-like cell that comes from the Earth and "fermentans"- Latin for "fermenting."
Approaches based on 16s rRNA gene sequence comparison have allowed for detailed analyses of the affiliations of many bacterial groups. The phylogenetic affiliation of Geothrix fermentans as well as other soil bacteria such as Acidobacterium capsulatum and Holophoga foetida had not been established at the time of their initial isolation. More recent analysis 16s rRNA sequence data showed moderate similarity between these three genera supporting the likelihood that they may have differentiated from a common ancestor.
Geothrix fermentans
Holophaga foetida
Acidobacteriaceae
Geothrix fermentans is a rod-shaped strict anaerobe that can be found in aquatic soils in the Fe(III) reduction zone. As a strict anaerobe G. fermentans cannot grow in the presence of atmospheric oxygen that may be present in the ecological niche from which it was isolated. Geothrix fermentans does not form spores and is non-motile. This organism is one of the few freshwater, cultivable bacteria that exhibit metal respiration using Fe(III) oxide. Optimum temperature for growth is 35 °C with a range from 25 °C to 40 °C. This bacterium preferentially uses the organic acid acetate as an electron donor, but it can utilize several other organic acids for growth such as propionate and lactate. In addition to organic acids, G. fermentans can use fatty acids such as palmitate using Fe(III) as the sole electron acceptor.G. fermentans can also grow using other forms of iron and metals such as manganese, but it shows preference for iron or iron derivatives. Utilization of alternate electron acceptors by this organism depends on the electron donor present. For instance, it will utilize nitrate (NO3) and Mn(IV) as alternative electron acceptors when lactate is being used as the electron donor.
...
Wikipedia