Introduction
Type of pesticides
Advantage & disadvantages of pesticides
Degradation of pesticide
Microbial degradation of pesticides
Mode of microbial metabolism of pesticides
Strategies for biodegradation
Approaches for biodegradation of pesticide
Chemical reaction leading biodegradation of pesticide
Metabolism of pesticides by MO
Metabolism of DDT
•Introduction of bioremediation: Bioremediation refers to the process of using microorganisms to remove the environmental pollutants i.e. toxic wastes found in soil, water, air etc.
•In situ bioremediation:
It involves a direct approach for the microbial
degradation of xenobiotics at the sites of pollution
(soil, ground water).
•Types of in situ bioremediation:
Natural attenuation.
Engineered in situ bioremediation.
- Bioventing, biosparging, bioslurping,
phytoremediation.
•Ex situ bioremediation:
Waste or toxic pollutants can be collected from the polluted sites and bioremediation can be carried out at a designated place or site.
• Types of ex situ bioremediation
Land farming, windrow, biopiles, bioreactors.
•Microorganisms use in bioremediation:
A number of naturally occurring marine microbes
such as Pseudomonas sp. is capable of degrading oil and other hydrocarbons.
•Factors affecting bioremediation:
Nutrient availability, moisture content, pH, temperature, contaminant availability.
•References:
Satyanarayana U. Biotechnology. BOOKS AND ALLIED (P) Ltd.
Sharma P.D. Environmental Microbiology. RASTOGI PUBLICATIONS.
Gupta P.K. Biotechnology and Genomics. RASTOGI PUBLICATIONS.
Dubey R.C. A Textbook of Biotechnology. S Chand And Company Ltd.
Dubey R.C. A Textbook of Microbiology. S Chand And Company Ltd.
Willey/Sherwood/Woolverton. Prescott’s Microbiology. McGRAW-HILL INTERNATIONAL EDITION.
www.sciencedirect.com/bioremediation.
•Introduction of bioremediation: Bioremediation refers to the process of using microorganisms to remove the environmental pollutants i.e. toxic wastes found in soil, water, air etc.
•In situ bioremediation:
It involves a direct approach for the microbial
degradation of xenobiotics at the sites of pollution
(soil, ground water).
•Types of in situ bioremediation:
Natural attenuation.
Engineered in situ bioremediation.
- Bioventing, biosparging, bioslurping,
phytoremediation.
•Ex situ bioremediation:
Waste or toxic pollutants can be collected from the polluted sites and bioremediation can be carried out at a designated place or site.
• Types of ex situ bioremediation
Land farming, windrow, biopiles, bioreactors.
•Microorganisms use in bioremediation:
A number of naturally occurring marine microbes
such as Pseudomonas sp. is capable of degrading oil and other hydrocarbons.
•Factors affecting bioremediation:
Nutrient availability, moisture content, pH, temperature, contaminant availability.
•References:
Satyanarayana U. Biotechnology. BOOKS AND ALLIED (P) Ltd.
Sharma P.D. Environmental Microbiology. RASTOGI PUBLICATIONS.
Gupta P.K. Biotechnology and Genomics. RASTOGI PUBLICATIONS.
Dubey R.C. A Textbook of Biotechnology. S Chand And Company Ltd.
Dubey R.C. A Textbook of Microbiology. S Chand And Company Ltd.
Willey/Sherwood/Woolverton. Prescott’s Microbiology. McGRAW-HILL INTERNATIONAL EDITION.
www.sciencedirect.com/bioremediation.
IntroductionDefinitionPescidesType of pesticidesFate of pesticides in environmentBiodegradation of pesticides in soil Criteria for biodegradation
Strategies for biodegradationDifferent approaches of biodegradationChemical reaction leading to biodegradationChanging the spectrum of toxicityExample of biodegradationAdvantageDisadvantage
Environmental Microbiology: Microbial degradation of recalcitrant compoundsTejaswini Petkar
A brief presentation on 'Microbial degradation of recalcitrant compounds'- their classes,their sources, the microorganisms involved and their modes of degradation,
Hydrocarbon are major constituents of crude oil and petroleum. They can be biodegraded by naturally-occurring microorganisms in freshwater and marine environments under a variety of aerobic and anaerobic conditions. The ability of microorganisms - bacteria, archaea, fungi, or algae - to break down hydrocarbons is the basis for natural and enhanced bioremediation. To promote biodegradation, amendments such as nitrogen and phosphorous fertilizer are often added to stimulate microbial growth and metabolism
Exposure to lead (Pb), zinc (Zn), cadmium (Cd), copper (Cu), and selenite (SeO3−2) consider the main heavy metals that threat human health. These heavy metals can interfere with the function of vital cellular components. Soil heavy metal contamination represents risks to humans and the ecosystem through drinking of contaminated groundwater, direct ingestion or the food chain, and reduction in food quality. Bioremediation means cleanup of polluted environment via transformation of toxic heavy metals into less toxic form by microbes or its enzymes. Otherwise, bioremediation by microbes has limitations like production of toxic metabolites. The efflux of metal ions outside the cell, biosorption to the cell walls and entrapment in extracellular capsules, precipitation, and reduction of the heavy metal ions to a less toxic state are mechanisms to metals’ resistance.
The ppt covers the following topics-
1. Introduction
2. Plastics
2.1 Definition and structure
2.2 Uses
2.3 Hazardous effect of Plastics
2.4 Ways to control plastic pollution
3. Biodegradation of Plastics
4. Conclusion
The USEPA defines biodegradation as a process by which microbial organisms transform or alter (through metabolic or enzymatic action) the structure of chemicals introduced into the environment.
According to the definition by the International Union of Pure and Applied Chemistry, the term biodegradation is “Breakdown of a substance catalyzed by enzymes in vitro or in vivo.
The term is often used in relation to ecology, waste management, biomedicine, and the natural environment (bioremediation) and is now commonly associated with environmentally friendly products that are capable of decomposing back into natural elements.
Biodegradable matter is generally organic material such as plant and animal matter and other substances originating from living organisms, or artificial materials that are similar enough to plant and animal matter to be put to use by microorganisms.
This ppt contains all types of Microbial Bioremediation methods . Everyone can understand clearly . Explaining with neat pictures and animation . Useful for presentation about Microbes in bioremediation . At last it contains a small animated video which helps to get clear view .
A pesticide can be defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.
Pesticides like insecticides, herbicides, fungicides, and various other substances are used to control or inhibit plant diseases and insect pests.
The positive aspect of application of pesticides renders enhanced crop/food productivity and drastic reduction of vector-borne diseases.
However excessive use of these chemicals leads to the microbial imbalance, environmental pollution and health hazards.
Due to these problems, development of technologies that guarantee their elimination in a safe, efficient and economical way is important.
IntroductionDefinitionPescidesType of pesticidesFate of pesticides in environmentBiodegradation of pesticides in soil Criteria for biodegradation
Strategies for biodegradationDifferent approaches of biodegradationChemical reaction leading to biodegradationChanging the spectrum of toxicityExample of biodegradationAdvantageDisadvantage
Environmental Microbiology: Microbial degradation of recalcitrant compoundsTejaswini Petkar
A brief presentation on 'Microbial degradation of recalcitrant compounds'- their classes,their sources, the microorganisms involved and their modes of degradation,
Hydrocarbon are major constituents of crude oil and petroleum. They can be biodegraded by naturally-occurring microorganisms in freshwater and marine environments under a variety of aerobic and anaerobic conditions. The ability of microorganisms - bacteria, archaea, fungi, or algae - to break down hydrocarbons is the basis for natural and enhanced bioremediation. To promote biodegradation, amendments such as nitrogen and phosphorous fertilizer are often added to stimulate microbial growth and metabolism
Exposure to lead (Pb), zinc (Zn), cadmium (Cd), copper (Cu), and selenite (SeO3−2) consider the main heavy metals that threat human health. These heavy metals can interfere with the function of vital cellular components. Soil heavy metal contamination represents risks to humans and the ecosystem through drinking of contaminated groundwater, direct ingestion or the food chain, and reduction in food quality. Bioremediation means cleanup of polluted environment via transformation of toxic heavy metals into less toxic form by microbes or its enzymes. Otherwise, bioremediation by microbes has limitations like production of toxic metabolites. The efflux of metal ions outside the cell, biosorption to the cell walls and entrapment in extracellular capsules, precipitation, and reduction of the heavy metal ions to a less toxic state are mechanisms to metals’ resistance.
The ppt covers the following topics-
1. Introduction
2. Plastics
2.1 Definition and structure
2.2 Uses
2.3 Hazardous effect of Plastics
2.4 Ways to control plastic pollution
3. Biodegradation of Plastics
4. Conclusion
The USEPA defines biodegradation as a process by which microbial organisms transform or alter (through metabolic or enzymatic action) the structure of chemicals introduced into the environment.
According to the definition by the International Union of Pure and Applied Chemistry, the term biodegradation is “Breakdown of a substance catalyzed by enzymes in vitro or in vivo.
The term is often used in relation to ecology, waste management, biomedicine, and the natural environment (bioremediation) and is now commonly associated with environmentally friendly products that are capable of decomposing back into natural elements.
Biodegradable matter is generally organic material such as plant and animal matter and other substances originating from living organisms, or artificial materials that are similar enough to plant and animal matter to be put to use by microorganisms.
This ppt contains all types of Microbial Bioremediation methods . Everyone can understand clearly . Explaining with neat pictures and animation . Useful for presentation about Microbes in bioremediation . At last it contains a small animated video which helps to get clear view .
A pesticide can be defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.
Pesticides like insecticides, herbicides, fungicides, and various other substances are used to control or inhibit plant diseases and insect pests.
The positive aspect of application of pesticides renders enhanced crop/food productivity and drastic reduction of vector-borne diseases.
However excessive use of these chemicals leads to the microbial imbalance, environmental pollution and health hazards.
Due to these problems, development of technologies that guarantee their elimination in a safe, efficient and economical way is important.
Agricultural inputs, list of agricultural inputs and Insecticide used in Bang...MD. ZANE ALAM
Agricultural inputs are defined as products permitted for use in organic farming. These include feedstuffs, fertilizers and permitted plant protection products as well as cleaning agents and additives used in food production.
Biodegradation or biological degradation is the phenomenon of biological transformation of organic compounds by living organisms, particularly the microorganisms.
Biodegradation basically involves the conversion of complex organic molecules to simpler (and mostly non-toxic) ones. The term biotransformation is used for incomplete biodegradation of organic compounds involving one or a few reactions. Biotransformation is employed for the synthesis of commercially important products by microorganisms.
Bioremediation refers to the process of using microorganisms to remove the environmental pollutants i.e. the toxic wastes found in soil, water, air etc. The microbes serve as scavengers in bioremediation. The removal of organic wastes by microbes for environmental clean-up is the essence of bioremediation. The other names used (by some authors) for bioremediation are bio-treatment, bio-reclamation and bio-restoration.
It is rather difficult to show any distinction between biodegradation and bioremediation. Further, in biotechnology, most of the reactions of biodegradation/bioremediation involve xenobiotic.
Recent Advances in Biopesticides BY Ghulam Murtazamurtaza8513
Biopestides are being manufactured all across the world but due to limited resources the research in biopesticides is not upto the mark. however advancement has been made in recent decades to protect crops from the attack of different insect pest in order to meet the agricultural productivity.
A pesticide is any substance used to kill, repel, or control certain forms of plant or animal life that are considered to be pests. Pesticides include herbicides for destroying weeds and other unwanted vegetation, insecticides for controlling a wide variety of insects, fungicides used to prevent the growth of molds and mildew, disinfectants for preventing the spread of bacteria, and compounds used to control mice and rats. Because of the widespread use of agricultural chemicals in food production, people are exposed to low levels of pesticide residues through their diets. Scientists do not yet have a clear understanding of the health effects of these pesticide residues. The Agricultural Health Study, an ongoing study of pesticide exposures in farm families, also posts results online. Other evidence suggests that children are particularly susceptible to adverse effects from exposure to pesticides, including neurodevelopmental effects. People may also be exposed to pesticides used in a variety of settings including homes, schools, hospitals, and workplaces.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Natural farming @ Dr. Siddhartha S. Jena.pptxsidjena70
A brief about organic farming/ Natural farming/ Zero budget natural farming/ Subash Palekar Natural farming which keeps us and environment safe and healthy. Next gen Agricultural practices of chemical free farming.
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
2. Content
• Introduction
• Type of pesticides
• Advantage & disadvantages of pesticides
• Degradation of pesticide
• Microbial degradation of pesticides
• Mode of microbial metabolism of pesticides
• Strategies for biodegradation
• Approaches for biodegradation of pesticide
• Chemical reaction leading biodegradation of pesticide
• Metabolism of pesticides by MO
• Metabolism of DDT
4. Introduction
• A pesticide is defined as a chemical agent used to destroy
or control pests. The root word is the Latin word “cida”
which means to kill.
• pesticide use is not just a modern practice (Hayes, 1991).
Perhaps the first recorded use of pesticide was around
1550 B.C., when Egyptians used unspecified chemicals to
drive fleas from homes.
• modern times, however, pesticide use has been much
more prevalent, and by 1990, about 300 insecticides were
in use.
5. Definition of Pesticides
The Food and Agriculture Organization (FAO) has defined
pesticide as:
• A pesticide is any substance or mixture of substances
intended for preventing, destroying, repelling, or
mitigating any pest (insects, mites, nematodes, weeds,
rats, etc.), including insecticide, herbicide, fungicide, and
various other substances used to control pests. The
definition of pesticide varies with times and countries.
However, the essence of pesticide remains basically
constant: it is a (mixed) substance that is poisonous and
efficient to target organisms and is safe to non-target
organisms and environments.
6. Types of Pesticides
These are grouped according to the types of pests which
they kill:
Grouped byTypes of PestsThey Kill
1. Insecticides – insects
2. Herbicides – plants
3. Rodenticides – rodents (rats & mice)
4. Bactericides – bacteria
5. Fungicides – fungi
6. Larvicides – larvae
7. Based on how biodegradable they are:
Pesticides can also be considered as:
1. Biodegradable:
The biodegradable kind is those which can be broken down
by microbes and other living beings into harmless
compounds.
2. Persistent:
While the persistent ones are those which may take
months or years to break down.
Another way to classify these is to consider those that are
chemical forms or are derived from a common source or
production method.
9. Persistence of some pesticides in the
environment
Pesticides
Aldrin >15YEARS
Chlordane >15YEARS
DDT >15YEARS
Dieldrin >15YEARS
Endrin >14YEARS
Malathion 3YEARS
Parathion >16YEARS
PCP >5YEARS
Simazine 2YEARS
2,4,5T 190 DAYS
10. Based on Chemical Composition
Organophosphate:
Most organophosphates are insecticides, they affect the
nervous system by disrupting the enzyme that regulates a
neurotransmitter.
Carbamate:
Similar to the organophosphorus pesticides, the carbamate
pesticides also affect the nervous system by disrupting an
enzyme that regulates the neurotransmitter. However, the
enzyme effects are usually reversible.
Organochlorine insecticides:
They were commonly used earlier, but now many countries
have been removed Organochlorine insecticides from their
market due to their health and environmental effects and
their persistence (e.g., DDT, chlordane, and toxaphene).
11. Pyrethroid:
These are a synthetic version of pyrethrin, a naturally
occurring pesticide, found in chrysanthemums(Flower).
They were developed in such a way as to maximize their
stability in the environment.
Biopesticides:
The biopesticides are certain types of pesticides derived
from such natural materials as animals, plants, bacteria,
and certain minerals.
14. Advantages of Pesticides
The major advantage of pesticides is that they can
save farmers. By protecting crops from insects and
other pests. However, below are some other primary
benefits of it.
• Controlling pests and plant disease.
• Controlling human/livestock disease vectors and
nuisance organisms.
• Controlling organisms that harm other human
activities and structures.
15. Disadvantage of pesticides
• The toxic chemicals in these are designed to deliberately
released into the environment. Though each pesticide is
meant to kill a certain pest, a very large percentage of
pesticides reach a destination other than their target.
Instead, they enter the air, water, sediments, and even
end up in our food.
• Pesticides have been linked with human health hazards,
from short-term impacts such as headaches and nausea
to chronic impacts like cancer, reproductive harm.
• The use of these also decreases the general biodiversity
in the soil. If there are no chemicals in the soil there is
higher soil quality, and this allows for higher water
retention, which is necessary for plants to grow.
16. Impacts on Environment
Impacts on non-target organism
• Most insecticides once applied to kill pests; it may also
adversely nontarget organisms such as earthworm, natural
predators and pollinator.
Loss of biodiversity
• Biodiversity is often considered as a measure of the healthy
biological systems.
Impacts on soil micro-flora
• A major portion of the non-target pesticides from
agriculture application and other sources may accumulates
in soil.
19. Degradation of pesticide
Pesticide degradation is the breaking down of toxic
pesticides into a nontoxic compounds and, in some cases,
down to the original elements from which they were
derived.
In general there are three ways to degrade pesticides:
1. Physical
2. Chemical
3. Biological (microbial degradation)
21. Biodegradation of pesticides
Biodegradation is a process by which a pesticide is transformed
into a benign substance that is environmentally compatible with
the site to which it was applied.
The degradation or breakdown of pesticides can occur in plants,
animals, and in the soil and water.
However the most common type of biodegradation is carried out
in the soil by microorganisms, especially fungi and bacteria that
use pesticides as food source.
The soil fumigant methyl bromide, the herbicide dalapon, and
the fungicide chloroneb are examples of pesticides which are
degraded by microorganisms.
22. Among the various practice to decrease the load of pesticides
in soil and water, the degradation by micro-organisms has
given sufficient encouragement . Bollag (1974)
Suggested four major possibilities for transformation of
inactivation pesticides by microorganisms they are:
The pesticides is used as substrate and energy.
The pesticides undergo co-metabolism i.e. organism
transform it but cannot derive energy for growth from it.
The entire pesticide molecules or its intermediate can be
conjugated with naturally occurring compounds.
The pesticides is incorporated and accumulated with in the
organisms.
23. Factors affecting Biodegradation
1. Chemical structure of the compound
2. The capability of the individual microorganisms
3. Nutrient and O2 supply
4. Temperature and pH
24. Microorganism
Many micro organisms belonging to diverse groups i.e.
bacteria, actinomycetes, fungi are found to degrade
different pesticides they metabolic diversity of the micro
organisms enable them to degrade this chemical different
pesticides .
It is interesting to note that two taxonomically
microorganism may degrade the same pesticide in similar
pathway .
Examples: Achromobacter , agrobacterium, Enterobacter,
aspergillus, candida….etc
26. Mode of microbial metabolism of pesticides
There are two modes :
1. ENZAYMATIC TYPE
2. NON-ENZYMATIC TYPE
1. ENZYMATIC TYPE
This divided into three phases
a) Incidental metabolism of pesticides which cannot serve as
energy source.
b) Catabolism insecticides serve as energy source.
c) Detoxification serving as resistance mechanism.
27. 2. NON-ENZYMATIC TYPE
a) Photosynthetic breakdown
b) Contribution via PH change
c) Production of organic and inorganic reactants
d) Production of cofactors
28. Strategies for Biodegradation
For the successful biodegradation / bioremediation of a
given contaminant following strategies are needed.
• Passive/ intrinsic Bioremediation: It is the natural
bioremediation of contaminant by tile indigenous
microorganisms and the rate of degradation is very slow.
• Biostimulation: Practice of addition of nitrogen and
phosphorus to stimulate indigenous microorganisms in
soil.
• Bioventing: Process of Biostimulation by which gases
stimulants like oxygen and methane are added or forced
into soil to stimulate microbial activity.
• Bioaugmentation: It is the inoculation/introduction of
microorganisms in the contaminated site/soil to facilitate
biodegradation.
29. • Composting: Piles of contaminated soils are constructed
and treated with aerobic thermophilic microorganisms to
degrade contaminants. Periodic physical mixing and
moistening of piles are done to promote microbial
activity.
• Phytoremediation: Can be achieved directly by planting
plants which hyperaccumulate heavy metals or indirectly
by plants stimulating microorganisms in the rhizosphere.
• Bioremediation: Process of detoxification of
toxic/unwanted chemicals / contaminants in the soil and
other environment by using microorganisms.
• Mineralization: Complete conversion of an organic
contaminant to its inorganic constituent by a species or
group of microorganisms.
30. Chemical Reactions Leading to
Biodegradation
The biodegradation of pesticides, is often complex and involves a
series of biochemical reactions:
• Detoxification: Conversion of the pesticide molecule to a non-
toxic compound. A single chance in the side chain of a complex
molecule may render the chemical non-toxic.
• Degradation: The breaking down / transformation of a complex
substrate into simpler products leading finally to mineralization.
e.g. Thirum (fungicide) is degraded by a strain of Pseudomonas
and the degradation products are dimethylamine, proteins,
sulpholipaids, etc.
• Conjugation: In which an organism make the substrate more
complex or combines the pesticide with cell metabolites.
Conjugation is accomplished by those organisms catalyzing the
reaction of addition of an amino acid, organic acid or methyl
crown to the substrate, for e.g., in the microbial metabolism of
sodium dimethyl dithiocarbonate, the organism combines the
fungicide with an amino acid molecule normally present in the cell
and thereby inactivate the pesticides/chemical.
31. • Activation: It is the conversion of non-toxic substrate
into a toxic molecule, for e.g. Herbicide, 4-butyric acid (2,
4-D B) and the insecticide Pharate are transformed and
activated microbiologically in soil to give metabolites
that are toxic to weeds and insects.
• Changing the spectrum of toxicity: Some
fungicides/pesticides are designed to control one
particular group of organisms / pests, but they are
metabolized to yield products inhibitory to entirely
dissimilar groups of organisms, for e.g. the fungicide
PCNB fungicide is converted in soil to chlorinated
benzoic acids that kill pests.
• Leaching: Since many of the pesticides can be
solubilized, they are removed by leaching.
32. Metabolism of pesticides by MO
Metabolism of pesticides may involve a three-phase
process:
• Phase I
• Phase II
• Phase III
Phase I- In Phase I metabolism, the initial properties of a
parent compound are transformed through oxidation,
reduction, or hydrolysis to generally produce a more water-
soluble and usually a less toxic product than the parent.
33. Phase II- The second phase involves conjugation of a
pesticide or pesticide metabolite to a sugar or amino acid,
which increases the water solubility and reduces toxicity
compared with the parent pesticide.
Phase III- The third phase involves conversion of Phase II
metabolites into secondary conjugates, which are also
non-toxic. In these processes fungi and bacteria are
involved producing intracellular or extra cellular enzymes
including hydrolytic enzymes, peroxidases, oxygenases,
etc.
34. Metabolism of DDT
DDT was used to control insects duringWorldWar II, and
then as an agricultural insecticide. Almost all uses of DDT
were banned in most developed countries in the 1970s–
1980s. In some countries, DDT was applied to the inside
walls of homes to kill or repel mosquitoes.
Dichlorodiphenyltrichloroethane (DDT) is an
organochlorine.
Its degradation by Phanerochaeta chysosporium is well
established chlorine substituents make DDT more resistant
for degradation how ever the production of two alginolytic
oxidase along with mono and dioxygenases convert the
DDT into co2