Phytoremediation uses plants and their associated rhizospheric microflora to remove or break down pollutants in soils, sediments and groundwater. Plants can absorb, sequester, and extract inorganic and organic pollutants like metals, pesticides and hydrocarbon compounds. The microbes in the rhizosphere also play a key role in degrading pollutants through secretions from plant roots that serve as carbon and energy sources. This process occurs through various mechanisms like accumulating metals in harvestable tissues, transforming pollutants to less toxic forms, or stabilizing pollutants to limit their mobility.

1. phytoremediation
Microbe assisted
By M.pooya naghshbandi
Bioremediation and Sustainability_
Research and Applications (2012)

2. Phytoremediation is the use of plants to erase, destroy, or
sequester pollutant from the surroundings moreover to
return them safe.
different kinds of mechanism to remove inorganic or
organic pollutant
Pollutant detoxification mechanism involved in plants is
quite similar to that involved in animals and is based on
"green liver concept".
plant associated rhizospheric microflora play a pivotal role
in degrading inorganic/organic pollutants.
The word phytoremediation was primary spawn in 1991 to
remediate soil and ground water by using plants
Bioremediation and Sustainability_ Research and Applications (2012)

3. Phytoremediation‫آلی‬ ‫ترکیبات‬ Phytoremediation‫عنصری‬ ‫ترکیبات‬(‫فلزی‬)
targets
Polychlorinated biphenyls
(PCBs) such as Dioxin;
Polycyclic aromatic
hydrocarbons (PAHs) such
as Benzoapyrene;
Nitroaromatics such as
Trinitrotoluene (TNT);
linear halogenated
hydrocarbons such as
Trichloroethylene (TCE);
herbicides and pesticides
targets
Lead, Cadmium,
Chromium, Arsenic,
Caesium, Mercury
and various
radionuclides such as
Uranium, Tritium,
Strontium,
Technetium.
strategy
-Direct
Phytoremediation
- Indirect
phytoremediation /
rhizoremediation
strategy
-extraction and
translocation of metals to
above ground tissues
-concentrate them in
harvestable plant parts,
-transformation of the
element to less toxic
form
- stabilization/or to
sequester element in
roots to reduce the
mobility andBioremediation and Sustainability_ Research and Applications (2012)

4. Types of Phytotechnology

6. Strategies Used in
Phytoremediation
of Inorganic Pollutant
Bioremediation and Sustainability_ Research and Applications (2012)

7. Plants are not only capable to accumulate metals that
have some biological role (ex. Cu, Mn, Fe, Zn, Mo
etc) but can also accumulate some nonessential
metals (ex. Cd, Cr, Pb, Co, Ag, Se, Hg)
root > leaf > stem > fruit
Methyl mercury [CH3Hg+ ]
 Mercuric ion reductase catalyzes conversion of Hg
(II) into Hg (0) . A NADPH dependent FAD containing
disulfide oxidoreductase enzyme that encodes from a
bacterial mer A gene.
 Methyl mercury can also be converted into Hg (II) by
using an organomercurial lyase enzyme. A bacterial
mer B gene encodes this enzyme.
 When this gene isolated from bacteria and
transferred in plants they become more resistant to
mercury.
Bioremediation and Sustainability_ Research and Applications (2012)

8. Strategies Used in
Phytoremediation
of Organic Pollutant
Bioremediation and Sustainability_ Research and Applications (2012)

9. refers to plant ability to secret enzymes that can
degrade organic contaminant.
Plant roots secret some soluble organic molecule
that act as biosurfactant like, rhamnolipid to
enhance the bioavailability of organic pollutant
[67]. They work by raising water solubility and
bacterial degradation of organic pollutant.
Synthetic biosurfactant like Triton X-100, SDS
(Sodium dodecyl sulphate) mimic natural
biosurfactant, and are widely used to enhance
bioavailability and uptake of organic pollutant by
plant roots
Bioremediation and Sustainability_ Research and Applications (2012)

10. Bioremediation and Sustainability_ Research and Applications (2012)

11. microbe assisted phytoremediation in which plants do not
play directly instead, microbe present in rhizosphere
plays an important role in degradation of organic
contaminant.
Plant secrete some kind of photosynthates in their root
exudates like sugars, organic acids, amino acids and
large organic compounds to enhance the growth and
metabolic activities of contaminant degrading microbes
present in rhizosphere. These microbes utilize root
exudates as carbon and energy source for their growth
For effective root colonization plants secrete some
aromatic compounds, for example, flavonoids and
coumarins, which are ultimately, degrade by rhizospheric
microbes (to use them as C and N source).
Bioremediation and Sustainability_ Research and Applications (2012)

12. Density of bacteria present in rhizospheric soil is about 2
to 4 times greater than that of un vegetated soil
Potent bacterial root colonization is generally depend :
 number of bacterial traits involving production of water
soluble B7 (Biotin) and B1 (Thiamine) vitamin
 induction of O-antigen polysaccharide
 fabrication of aminoacids and isoflavonoids induced
efflux pump.
Some organic contaminants like PCBs, PAHs moreover
PHC structurally mimic these organic compounds and
hence can easily be taken up by rhizospheric microbes
as a source of carbon and energy, favouring a natural
degradation process of these contaminants
Bioremediation and Sustainability_ Research and Applications (2012)

13. The most active soil bacteria for the degradation of PAHs are
Pseudomonas, Mycobacterium, Flavobacterium, Acintobacter,
Arthrobacter, Bacillus moreover Nocarida
Bioremediation and Sustainability_ Research and Applications (2012)

14. Bioremediation and Sustainability_ Research and Applications (2012)

15. Thanks for your attention
Bioremediation and Sustainability_
Research and Applications (2012)