''Cupriavidus metallidurans'' is a non-spore-forming,

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

bacterium which is adapted to survive several forms of heavy metal stress.

As a model and industrial system

Cupriavidus metallidurans is a bacterial species that belongs to the same family as ''

Ralstonia solanacearum ''Ralstonia solanacearum'' is an aerobic non-spore-forming, Gram-negative, plant pathogenic bacterium. ''R. solanacearum'' is soil-borne and motile with a polar flagellar tuft. It colonises the xylem, causing bacterial wilt in a very wide ran ...

'', a plant pathogen. This species is of

ecological Ecology () is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely re ...

and industrial importance, as its relatives dominate

mesophilic A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from . The optimum growth temperature for these organisms is 37 °C (about 99 °F). The term is mainly applied ...

environments contaminated with heavy metals. ''C. metallidurans'' is used in the industrial sector for both heavy metal remediation and sensing. This

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cellu ...

chemolithoautotroph Overview Most chemoautotrophs are lithotrophs, using inorganic electron donors such as hydrogen sulfide, hydrogen gas, elemental sulfur, ammonium and ferrous oxide as reducing agents and hydrogen sources for biosynthesis and chemical ener ...

is capable of growing in a mineral salts environment with H₂, O₂, and CO₂ without an organic carbon source. Its energy-providing subsystem is composed of only the

hydrogenase A hydrogenase is an enzyme that Catalysis, catalyses the reversible Redox, oxidation of molecular hydrogen (H2), as shown below: Hydrogen oxidation () is coupled to the reduction of electron acceptors such as oxygen, nitrate, Ferric, ferric i ...

, the

respiratory chain An electron transport chain (ETC) is a series of protein complexes and other molecules which transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this ...

, and the F1F0-ATPase, which remain separate from the

anabolic Anabolism () is the set of metabolic pathways that construct macromolecules like DNA or RNA from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catab ...

subsystems. ''C. metallidurans'' can also degrade

xenobiotics A xenobiotic is a chemical substance found within an organism that is not naturally produced or expected to be present within the organism. It can also cover substances that are present in much higher concentrations than are usual. Natural compo ...

in conditions with high levels of heavy metals. Strain CH34 has adapted to these harsh conditions through multiple heavy-metal resistance systems, encoded by the two indigenous megaplasmids, pMOL28 and pMOL30, on its chromosome(s).

Ecology

CSIRO ScienceImage 3908 Coloured scanning electron image of bacterioform gold on a gold grain from the Hit or Miss Mine in northern Queensland

''C. metallidurans'' plays a vital role, together with '' Delftia acidovorans'', in the formation of

gold nugget A gold nugget is a naturally occurring piece of Native metal, native gold. Watercourses often concentrate nuggets and finer gold in placer deposit, placers. Nuggets are recovered by placer mining, but they are also found in residual deposits wher ...

s. It precipitates metallic gold from a solution of

gold(III) chloride Gold(III) chloride, traditionally called auric chloride, is an inorganic compound of gold and chlorine with the molecular formula . The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. It ...

, a compound highly toxic to most other microorganisms.

As a pathogen

A case of a 74 year old man infected with ''Cupriavidus metallidurans'' has been documented, possibly raising concerns about the safety of using the bacteria for industrial purposes.

References

External links

Article at Live ScienceType strain of ''Cupriavidus metallidurans'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q136005 Burkholderiaceae Metallotolerants Bacteria described in 2001