1. Bioremediation Dr. Bhavesh Patel (M.Sc., Ph.D.) Principal
V.P. and R.P.T.P. Science College, Vallabh Vidyanagar -

2. What is Bioremediation?
“ It is a pollution treatment technology that uses biological systems to catalyze the destruction or transformation of various chemicals to less harmful forms.”

3. Key words Assimilation: Incorporation of elements in to biomass.
Dissimilation: Release of elements from biomass.
Recalcitrant: Nondegradable (difficult to degrade).
Xenobiotics: Compounds foreign to biological systems. Often refers to human made compounds that are resistant to biodegradation.

4. Bioremediation : Concept
Human interference – 18th Century
Synthesis of complex compounds like: Pesticides, Solvents,Fertilizers, Nitroaeromatics, Plastic etc.
Recalcitrant (xenobiotic)
Bioremediation
Mineralization or less harmful forms

5. Why Bioremediation?
Conventional technology involves moving large quantities of toxic waste, contaminated soil to incinerators, thus costly.
Bioremediation can be performed on site, thus economic.
In Bioremediation the end products are generally nontoxic. (if complete mineralization occurs)
Other activity at the contaminated site is relatively undisturbed.
Requires simple equipments.
ECOFRIENDLY

6. Limitations
Bioremediation is not the solution for all the environmental pollution problems.
It may take long time, if the conditions are not favorable.

7. Approaches to Bioremediation
Intrinsic Bioremediation
>Monitoring the natural biodegradation process.
Biostimulation
>Carry out environmental modification i.e. pH, temp., aeration, nutrients etc.
Bioaugmentation
>Seeding with pollutant degrading bacteria.
>Creating microbial consortia (co-metabolism).
>Molecular breading.

8. Targets Aerobic Aerobic cometabolic Anaerobic
Aromatic compounds Chlorinated solvent Chlorinated solvent
BTEX TCE Perchloroethylene
Phenol DCE TCE
Styrene Vinyl chloride DCE
Chlorobenzene Bromoform Nitro aromatics
Aniline MTBE TNT
Nitrobenzene HCFCs PCBs
Naphthalene PAHs
Solvents
Chlorinated solvents
Sulfur compounds
Fertilizers
BTEX-benzene,toluene,ethylbenzene,xylenes; DCE-dichloroethene; HCFC-hydrochlorofluorocarbon; MTBE- methyltertiarybutylether; PAH- poly aromatic hydrocarbon;PCB- poly chlorinated biphenyl; TCE- trichloroethene

9. The masters - Organisms
The white rot fungus Phanerochaete has extensive biodegradative capabilities. It is successfully used for :
Pesticides – DDT
Munitions – TNT
High MW polynuclear aromatics – Benzopyrene
Plastics – Polyethylene

10. Cont…
Bacteria Pseudomonas have also been widely used as seed culture for Trichloroethene (TCE), PCBs etc.
Microbial consortium can be used that include :
>Sulfate reducing bacteria
>Methanogenic bacteria
>Pseudomonas
>Alkaligens
>Acinetobacter

11. Cont… Genetically modified organisms :
Chakrabarty was the first to create a hydrocarbon degrading Pseudomonas putida by recombinant DNA technology that has ability to degrade over 100 different hydrocarbons.
Bacterium Deinococcus radiodurans has been modified to consume and digest toluene and ionic mercury from highly radioactive nuclear waste.

12. PCBs – Hard to treat
Poly Chlorinated Biphenyl has a pair of benzene ring in which Cl is substituted at H.
209 different kinds of PCBs are possible.
First made in 1881, Commercially available 1920, Monsanto sold it by trade name Aroclor.
PCB has high BP, low water solubility, low conductivity, hard to burn, acid-alkali resistant.
It is used in making adhesive, carbonless copy paper, insulators, lubricants, plasticizer, varnishes, epoxy paints etc.
1944 – PCB enters the food chain.
Fortunately Bioremediation is possible (Anaerobic-dehalogenation)

13. Worst oil spill Exxon supertanker – March 1989
11 million gallons of crude oil was spreaded over Alaska.
1000 miles of Alaskan shorelines were contaminated with oil.
This affect birds, aquatic ecosystem, plants.
Over 1 million $ spent per day.
Fertilizer were applied – Biostimulation.
Took 2-3 years – Bioremediation.

14. Thank You