This document discusses bioremediation and the use of microorganisms to degrade organic pollutants and remove contamination. It describes how bacteria, fungi and other microbes break down waste organic matter through metabolic processes. The document also discusses how genetic engineering can be used to design microorganisms capable of degrading specific contaminants more efficiently. Examples are provided of various bacteria and fungi that have been genetically modified or studied for their ability to break down pollutants like benzene, toluene, chlorobenzoate and heavy metals.

1. BY: AKASH RADHAKRISHNAN
ENVIRONMENT 3rd YEAR
01020705614
CBPGEC

2. • Bioremediation is the process of using organisms to neutralize or
remove contamination from waste1.
• At sites filled with waste organic material, bacteria, fungi, protists,
and other microorganisms keep on breaking down organic matter to
decompose the waste.
• Bioremediation works by providing these organisms with different
materials like fertilizer, oxygen and other conditions to survive. This
would help to break the organic pollutant at a faster rate.

3. • It uses no chemicals – One of the issues with using man-made
chemicals in the treatment and removal of contamination is that the
chemicals eventually make it into the water supply.
• It can allow waste to be recycled – Another major reason that
bioremediation is preferred is that once the waste is treated and the
contamination neutralized or removed, the waste itself can then be
recycled.

4. • Even though science and engineering has developed many ways to treat
organic matter but even to this date no man-made technique can rival the
efficiency with which MO's treat organic matter.
• MO's here stand for a variety of organisms which are not seen by the naked
eye or are very small eg:- bacteria, protists, fungi etc.
• Microorganisms can decompose or transform hazardous substances into less
toxic metabolites or degrade to non-toxic end products
• At the beginning of the 80s the development of genetic engineering
techniques and intensive studying of metabolic potential of microorganisms
allowed to design genetically modified microorganisms(GMMs).

5. Fig. 1. Steps in molecular cloning
source-application of GMM's Wasilowski.A
• Genetic engineering is a modern technology,
which allows to design microorganisms capable
of degrading specific contaminants.
• The first step in GMM construction is selection of
suitable gene/s.
• Next, the DNA fragment to be cloned is inserted
into a vector and introduced into host cells. The
modified bacteria are called recombinant cells.
• The following step is production of multiple gene
copies and selection of cells containing
recombinant DNA.
• The final step includes screening for clones with
desired DNA inserts and biological properties.

6. • In 1981 in the USA the first two genetically modified strains of
Pseudomonas aeruginosa and Pseudomonas putida were patented
and were created by chakraborty and were known for their ability to
degrade Camphor, Salicylate and Napthalene2.
• Naphthalene-degrading Pseudomonas fluorescens represents the
first genetically engineered microorganism approved for field testing
in the USA for bioremediation purposes3.

7. • Pseudomas are gram negative bacteria which have
been studied very thoroughly over the years for
applications in bioremediation4.
• Some members of the genus are able to metabolise
chemical pollutants in the environment, and as a
result, can be used for bioremediation.
1. P. putida, which has the ability to degrade organic
solvents such as toluene.
2. P. mendocina, which is able to degrade toluene.
3. P. alcaligenes, which can degrade polycyclic
aromatic hydrocarbons.
fig2: Psuedonomas putida
source:- Dennis kunkel

8. • Dechloromonas aromatica- is a rod-shaped bacterium which
can oxidize aromatics including benzoate, chlorobenzoate, and
toluene, coupling the reaction with the reduction of oxygen,
chlorate, or nitrate. It is the only organism able to oxidize
benzene anaerobically.5
• Deinococcus radiodurans-Deinococcus radiodurans is a
radiation-resistant extremophile bacterium that is genetically
engineered for the bioremediation of solvents and heavy
metals.6
• Alcanivorax borkumensis-marine rod-shaped bacterium
which consumes hydrocarbons, such as the ones found in fuel,
and produces carbon dioxide. It grows rapidly in environments
damaged by oil, and has been used to aid in cleaning the more
than 830,000 gallons of oil from the Deepwater Horizon oil
spill in the Gulf of Mexico.7
Alcanivorax borkumensis,
Image©https://www.biotechnol
ogie.de

9. • Fungi have fundamentally important roles because of their participation in the
cycling of elements through decomposition and transformation of organic and
inorganic materials.
• These characteristics can be translated into applications for bioremediation
which could break down organic compounds and reduce the risks of metals
• the white rot species Phanerochaete chrysosporium was discovered to
metabolize multiple key environmental pollutants.8
• they degrade lignin extracellularly through its hyphal extension. This allows
them to access soil contaminants that other organisms are incapable of and
maximize surface area for enzymatic interaction. These inexpensive fungi can
tolerate extreme environmental conditions, such as pH, temperature, and
moisture content

10. 1. https://www.conserve-energy-future.com/what-is-
bioremediation.php[1]
2. Wasiloski. D, Swedziol.Z, Mrozik.A “The applicability of genetically
modified microorganisms in bioremediationof contaminated
environments”[2,3,4,]
3. https://microbewiki.kenyon.edu/index.php/Bioremediation.[5,6,7]