Microbes for heavy metal ...

Microbes for heavy metal removal

~~Microorganisms can be used to remove particular heavy metals from wastewater streams. There are two ways of doing it with something like iron.

The first is through biosorption, where the microorganisms take up the iron into their biomass. The biomass can then be removed from the water (through filtration, centrifugation, etc.), taking with it a large proportion of the metal. The biomass can then be incinerated and you are left with an iron ore, which can be sold. All microorganisms produce siderophores (iron chelators) with varying levels of efficiency so we could probably find something that was particularly effective in their waste water and then stimulate this microorganism.

The second process is through precipitation of the metal.  SRB can actually be very helpful here as they precipitate iron out as iron sulphide!

Generally what happens will be a mixture of biosorption and bioprecipitation.

I don’t think there is a F. thioxidans but Thiobacillus thiooxidans  (now known as Acidithiobacillus thiooxidans) has been used for ‘bioleaching’ or ‘mining with microbes’ as they convert iron in mineral ores to a soluble form, which then ‘leaches’ out of the rock in water and is then converted back to an insoluble form and harvested. It will depend on the iron oxidation state in the water as to whether these will be useful or not.

A mixed microbial consortium will always work better than a pure culture microorganism anyway and the specific mechanism and type of bugs they need will vary depending on the water chemistry and the oxidation state of the iron in the water.

Incidentally, you can also remediate waters for arsenic and mercury by using microorganisms to modify the toxic forms to less toxic forms.

I have a few contacts who conduct research in this area and as most of the bugs are the same ones we’re dealing with in oil reservoirs. Need more help then contact me for further details.