Exiguobacterium was originally discovered by Collins et al. in 1984, in an alkaline potato processing plant. Since that time, other strains of this bacteria have been found in the Hot Springs of Yellowstone National Park, the extreme frost of Siberia and the glaciers in Greenland.
Importance to Microbiology
The ability of exiguobacterium to survive in extreme temperatures (-12C - 55C)and grow within a large range of pH (5-11) make this bacteria an important area of study. It has also shown to be tolerant of UV radiation and heavy metal stress.
Domain: Bacteria, Phylum: Firmicutes, Class: Bacilli, Genus: Exiguobacterium, Species: Unknown
History and Description
Zoogloea can be found free-living in fresh waters that have been organically polluted. It can also grow in waste-water treatment at all levels. Zoogloea are aerobic, chemoorganotrophic. For energy they use oxidative metabolism. Zoogloea has been studied as a pure culture.
Exiguobacterium are small, rod shaped bacteria, or coccobacilli. Stains performed on our organism revealed a positive gram stain and small capsules. This organism was negative for endospores.
G/C is roughly 64.5%
Zoogloea plays an important role in waste-water treatment because it is capable of lowering demand for biological oxygen. It also has the capable of enhancing the formation of sludge. The activated sludge bacterium that create habitats for activated sludge flocs. It has been studied that high amounts of Zoogloea ramigera normally correlates with overloading sewage plants. The flocs that form settle at the bottom of the water-waste treatment tank and help the purification process. This species also plays a role in poly-B-hydroxybutyrate (PHB) production and biosorption of metals.
Interaction with other Organisms
PHB is produced whenever both a carbon source is highly present as well as B-ketothiolase. Biological Oxygen Demand (BOD) is reduced by Z. ramigera. The species is also known to use Mn-oxidation metabolism, because the matrix made by Zoogloea takes in and concentrated metal in water sources.