genetically modified organisms used for remediation of heavy metals, radioactive waste for bio-remediation

1. COURSE WORK SEMINAR (II) ON
GENETICALLY MODIFIED ORGANISMS FOR BIOREMEDIATION
Presented by
Swayam Prakash Nanda
Regd No:1981002011
Environmental Science
Department of chemistry

2. Contents
• Introduction
• Objective
• bioremediation strategies
• Factors affecting bioremediation
• Introduction of GMO
• Technique used for GMO
• Advantages and disadvantages
• Conclusion
• References

3. BIOREMEDIATION
 Bioremediation refers to the process of using microorganisms or plants to
remove the environmental pollutants or prevent pollution.
 The removal of organic wastes by microbes for environmental clean-up is
the essence of bioremediation.
 The other names used for bioremediation are biotreatment, bioreclamation
and biorestoration.
 Xenobiotics broadly refer to the unnatural, foreign and synthetic
chemicals such as pesticide, herbicide & other organic compounds.
TYPES OF BIOREMEDIATION :
1. Biostimulation
2. Bioaugmentation
3. Intrinsic bioremediation

4. BIOREMEDIATION IS A TRIPLE-CORNERS PROCESS
Pollutants
Inorganic Inorganic
Environments Organisms
Soil
Water
Air
Microorganisms
Plants
Enzymes

5. Objective of taking genetically modified organisms :-
 More efficient in bioremediation process.
 Survive in critical environmental conditions.
 Can be monitored easily.
 Beautification of a contaminated environment can be done by modified ornamental plants.
 Contaminants have less chance to enter food chain.
 Speed recovery of contaminated site is possible.

6. • Waste material is examined & certain microbes or
plants are isolated based on their efficacy at
digesting and converting the waste.
• Indigenous or local bacteria is to be used.
• The bacteria then go through several steps of
cultures and process for performance testing.
• The suitable bacteria are placed back in the
waste environment.
• They grow & thrive & in the process digest &
convert the waste into Carbon dioxide & water.
• The right temperature, nutrients, and food also
must be present.
• Conditions may be improved by adding
“amendments.”
How Does It Work?

7. ESSENTIAL FACTORS FOR MICROBIAL
BIOREMEDIATION
Factor Desired Conditions
Microbial population
Suitable kinds of organisms that can
biodegrade all of the contaminants.
Oxygen
Enough to support aerobic biodegradation
(about 2% oxygen in the gas phase or 0.4
mg/litter in the soil water).
Water
Soil moisture should be from 50–70% of the
water holding capacity of the soil.
Nutrients
Nitrogen, phosphorus, sulphur, and other
nutrients to support good microbial growth.
Temperature
Appropriate temperatures for microbial
growth (10–40˚C).
pH Best range is from 6.5 to 7.5

8. GENETICALLY MODIFIED
ORGANISM

9.  The genetically engineered micro organism (GEMs)enhance the ability of degrading the contaminants. It is also said to
be as a “bioaugmentation”.
 These organism is constructed by recombinant DNA technology.
 Some examples of GMOs action on various xenobiotics.
GENETICALLY MODIFIED ORGANISM
 any organism whose genetic material has been altered using genetic engineering techniques.
GMOs Xenobiotic
P. olevorans Alkane
Pseudomonas diminuta parathion
P. cepacia 2, 4, 5-Trichlorophenol
Alcaligenes sp 2, 4-dichlorophenoxy acetic acid
Acinetobacter sp 4- chlorobenzene

10. Some examples of genetically modified organism
 The bacterium Deinococcus radiodurans (the most radio resistant organism
known) has been modified to consume and digest toluene and ionic mercury
from highly radioactive nuclear waste.
Strains of Deinococcus radiodurans

11. mechanism of making superbug
 Prof. Ananda Mohan Chakraborty et al. (1979) developed and patented a “superbug” that
degraded petroleum (camphor, octane, xylene, and naphthalene) by plasmid transfers.
 transformed Pseudomonas putida with plasmids derived from four different bacteria
involved in hydrocarbon degradation.

12. Modified plants and genes for phytoremediation
Gene Source Target plant Phenotype Reference
SMT A. bisulcatus B. juncea Se volatization asb DMSe and DMDSe from media with 200 μM SeO4− increased 3 times (10% of
Se evapotrated as DMDSe)
LeDuc et al.,
2004
CAX2 A. thaliana N. tabacum 2.8, 2.5 and 1.3 times higher biomass when grown, respectively, on media with 3 μM Cd2+, 500
μM Mn2+ and 150 μM Zn2+, then in roots 1.5 and 1.3 times higher Cd and Zn levels. Amount of
metal accumulated per plant growing on media with 3 μM Cd2+, 500 μM Mn2+ and 150 μM Zn2+
was higher 3.4, 2.3 and 1.9times, respectively
Korenkov et al.,
2007b
YCF1 S. cerevisiae A. thaliana 2.2 and 1.8 times higher biomass when grown on media with 60 μM Cd2+ and 900 μM Pb2+,
respectively. Shoots accumulated 1.5 times higher metal levels from media with 70 μM Cd2+ or
750 μM Pb2+
Song et al., 2003
gshI E. coli B. Juncea 2.1 times longer roots in media with 200 μM Cd2+. By 90% higher shoot Cd levels when grown in
media with 50 μM Cd2+.
When grown on polluted soilb, shoots showed 1.5, 2.0, 2.0 and 3.1 times higher Cd, Zn, Cu and Pb
levels, respectively
Zhu et al., 1999a
Bennett et al.,
2003
OAS-TL S. oleracea N. tabacum On medium with 300 μM Cd2+: 2.5 times higher biomass, 2.8 times longer roots. On medium with
500 μM Ni2+ 1.3 times higher biomass, 4.2 times longer roots. On medium with 250 μM
SeO4
− 1.5 times higher biomass, 1.8 times longer roots. Always higher chlorophyl content. When
grown in media with 100 μM Cd2+, the Cd levels 1.4 times increased in shoots and 4 times reduced
in roots.
Kawashima et al.,
2004
TaPCS1 T. aestivum N. glauca 1.6 times longer roots on media with 800 μM Pb2+ or 50 μM Cd2+.
Shoots of transformed line NgTP1 accumulated from polluted soil. respectively, 6.0, 3.3, 4.8, 18.2
and 2.6 times more Pb, Cd, Zn, Cu and Ni.
Gisbert et al.,
2003
Martínez et al.,
2006
merP Bacillus
megaterium
A. thaliana Capable of germination and growth on media with 12.5 μM Hg2+ accumulating 5.35 μg Hg2+g of
fresh seedling weight.
Hsieh et al., 2009

13. Purpose of taking higher genetically modified plants:-
 For large scale remediation in contaminated site.
 High root coverage area causes high accumulation and degradation.
 Both ground water and soil contaminant can be removed.
 Useful by-product generation.
 Prevents soil erosion by large root coverage and direct enzymatic action on contaminant by the microorganism present in
root zone.
 Flowering plants keep the polluted site pleasant.
 Landscape eco-tourism.

14. Pteris vittata Liriodendron
tulipifera
Eichhornia
crassipes
Brassica juncea Cannabis sativa Alyssum bertolonii
Some higher plants ( genetically modified)

15. Advantages
 More efficient than traditional methods of bioremediation.
 Over all efficiency of G.M. plants will be increases.
 Easy and enhanced method of cleaning environmental contaminant.
 Multiple contaminant may be degraded by GMO.
 The groundwater and soil can be treated at the same time by using in-situ bioremediation by using higher genetically
modified plants.

16. Disadvantages
 Risk of getting harmful organism or weed if the experiment goes wrong.
 May not be economically efficient.
 Upsetting the ecosystem.
 Ethical issues.
 Disrupting crop yield (may be).

17. Conclusion
 Recovery of a contaminated medium by using living organisms.
 Approach to enhance the degrading capability.
 Application in all types of contaminated fields.
 Effective process for bioremediation.
 Genetic engineered micro-organisms are developed for environmental clean-up process.
 Eco-friendly technology.
 Further research going on to degrade plastic waste which is a major problem for both aquatic and terrestrial environment
world wide.

18. References:-
 Chakrabarty, AM; Mylroie, JR; Friello, DA; Vacca, JG (1975). "Transformation of Pseudomonas putida and
Escherichia coli with plasmid-linked drug-resistance factor DNA". Proceedings of the National Academy of
Sciences of the United States of America 72 (9): 3647–51.
 Brar SK, Verma M, Surampalli RY, MisraK, Tyagi RD, Meunier N and Blais JF, “Bioremediation of hazardous
wastes: are view‖, Pract Periodical Hazard, Toxic Radioactive Waste Management”. 10:59-72, 2006.
 Urgun-Demirtas, M., Stark, B., & Pagilla, K. (2006). Use of Genetically Engineered Microorganisms (GEMs)
for the Bioremediation of Contaminants. Critical Reviews in Biotechnology, 26(3), 145–164.
 Bioremediation, its Applications to Contaminated Sites in India, Ministry of Environment & Forests.
 Text book of Biotechnology- U.sathyanarayana.