Topic: Bioremediation Category: Environment and Ecology
- Bioremediation is a waste management technique that involves the use of organisms to neutralize pollutants from a contaminated site.
- According to the United States EPA, bioremediation is a “treatment that uses naturally occurring organisms to break down hazardous substances into less toxic or non toxic substances”.
- Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated elsewhere.
- Some examples of bioremediation related technologies are phytoremediation, bioventing, bioleaching, landfarming, bioreactor, composting, bioaugmentation, rhizofiltration, and biostimulation.
- Bioremediation may occur on its own (natural attenuation or intrinsic bioremediation) or may only effectively occur through the addition of fertilizers, oxygen, etc., that help in enhancing the growth of the pollution-eating microbes within the medium (biostimulation).
- However, not all contaminants are easily treated by bioremediation using microorganisms. For example, heavy metals such as cadmium and lead are not readily absorbed or captured by microorganisms.
Genetic engineering approaches
- The use of genetic engineering to create organisms specifically designed for bioremediation has great potential.
- The bacterium Deinococcus radiodurans (the most radioresistant organism known) has been modified to consume and digest toluene and ionic mercury from highly radioactive nuclear waste.
- Releasing genetically augmented organisms into the environment may be problematic as tracking them can be difficult; bioluminescence genes from other species may be inserted to make this easier.
- Mycoremediation is a form of bioremediation in which fungi are used to decontaminate the area.
- One of the primary roles of fungi in the ecosystem is decomposition, which is performed by the mycelium.
- The mycelium secretes extracellular enzymes and acids that break down lignin and cellulose, the two main building blocks of plant fiber.
- These are organic compounds composed of long chains of carbon and hydrogen, structurally similar to many organic pollutants.
- The key to mycoremediation is determining the right fungal species to target a specific pollutant.
- Certain strains have been reported to successfully degrade the nerve gases VX and sarin.