Bacterium · Metal-binding survivor
Cupriavidus metallidurans
Isolated from metallurgical waste, it carries dedicated gene systems for cadmium, zinc, copper, lead, mercury, nickel and chromium, and nucleates metals into mineral form on its surface.
| Contaminant | What the research documents |
|---|---|
| Heavy metals | czc/cnr/pbr efflux systems plus extracellular polysaccharide nucleation into metal carbonates; documented in engineered treatment systems, thinner in soil |
From published research on the species, not tests of an Elm Dirt product. Studies often work with one strain, and sequencing identifies species, so results on a site are measured on that site.
On this page (5 sections)
What it is
Cupriavidus metallidurans was isolated from sediment in a zinc decantation tank at a metallurgical plant, where almost nothing survives. It has become the model organism for how bacteria handle heavy metals.
Peer-reviewed research shows Cupriavidus metallidurans can immobilize cadmium, zinc, copper, lead, mercury, cobalt, nickel and chromium. It is one of the 291 microbial species identified in Plant Juice by independent lab analysis (Biome Makers).
What the research shows
The genome of this species carries whole operons for metal resistance, among them czc for cadmium, zinc and cobalt, cnr for cobalt and nickel, and pbr for lead. Much of that machinery sits on two large plasmids [2,3].
Research groups have built the organism into inoculated sand filters and bioreactors to pull metals out of contaminated water and soil slurries. Pumps push metal ions out to the cell surface, where the bacterium’s polysaccharides act as nucleation sites and the metals crystallize, mostly as carbonates [1].
How it works
Since no organism destroys a metal, biology works by changing where a metal sits and what form it takes, from dissolved and mobile to locked in a mineral that stays put, and C. metallidurans pushes metals toward the locked form.
Immobilization can come undone, because a shift in soil pH, a change in oxidation state, or decaying organic matter can release what was bound, so any program that relies on it needs long-term monitoring instead of a single follow-up test.
Where it fits
It is the reference organism for bacteria living with metals, studied from its genes up to engineered treatment systems. It suits mixed-metal ground such as smelter fallout, mine tailings and brownfields; see heavy metals. On a site, an independent lab tracks metal mobility over months to a year or more.
Studies
- Diels L, Van Roy S, Taghavi S, Van Houdt R (2009). From industrial sites to environmental applications with Cupriavidus metallidurans. Antonie van Leeuwenhoek 96(2):247–258. doi:10.1007/s10482-009-9361-4
- Janssen PJ, et al. (2010). The complete genome sequence of Cupriavidus metallidurans strain CH34, a master survivalist in harsh and anthropogenic environments. PLoS ONE 5(5):e10433. doi:10.1371/journal.pone.0010433
- Mergeay M, et al. (2003). Ralstonia metallidurans, a bacterium specifically adapted to toxic metals: towards a catalogue of metal-responsive genes. FEMS Microbiology Reviews 27(2-3):385–410. doi:10.1016/S0168-6445(03)00045-7
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