1. VIVEKANANDHAARTS AND SCIENCE
COLLEGE FOR WOMEN,
Veerachipalayam, sankagiri, Salem
Presented by :
Subasri. M
I-Msc.Microbiology
Guided by:
Dr.R.Dinesh kumar,
Assistant professor,
Department of microbiology.
DEPARTMENT OF MICROBIOLOGY
SUBJECT :
BIOREMEDIATION
4. INTRODUCTION
• Bioremediation is a biotechnology technique that uses living organisms to remove
contaminants from soil, water, and other environments.
• It involves using the biological processes of organisms, mainly bacteria and fung to
transform contaminants to inert substances.
• Bioremediation is a waste management technique that uses naturally occurring
organisms to break down harmful materials into less toxic or non-toxic materials.
• It is currently the cheapest and has greater efficiency in the removal of
contaminants than conventional physicochemical methods.
5. INTRODUCTION
• Bioremediation stimulates the growth of certain microbes that use contaminants
as a source of food and energy.
• For example, certain microorganisms like merino bacter are known to break
down the harmful chemicals into safer non-toxic compounds.
• Bioremediation has several branches, including contaminated soil, oil spill
cleanup, and crime scene clean up.
6. FACTORS AFFECTING BIOREMEDIATION
• The monitoring of soil physically and chemically is a time-
consuming process, in order to measure the pollution of soil
after contamination in a shorter period of time microbial and
biochemical properties of the soil are to be determined.
• Bioremediation is a method that uses microorganisms to
degrade environmental pollutants or contaminants.
• The bioremediation process depends upon the different factors
for the removal of the contaminants, some of them are,
7. THE FACTORS ARE......
1. Concentration of the contaminants
2. Nutrients
3. Moisture content
4. Temperature
5. pH
6. Oxygen
7. Metal ions
8. Redox potential
9. Biogeochemical parameters
8. 1.CONCENTRATION OF THE CONTAMINANTS
• The concentration of the contaminants directly affects microbial activity.
• Lower the concentration of the contaminants there will be decreasing
rate of degrading enzymes produced by bacteria in the soil.
• Toxic effects are observed in presence of higher concentrations of
contaminants.
• The decomposition rate of catabolic enzymes can be increased by the
synergistic interactions between different components of the
contaminants.
9. 2. NUTRIENTS
• Carbon, nitrogen, phosphorus, potassium, and calcium are the basic
requirement for the growth of microorganisms, the concentration of the
nutrient availability directly affects the degradation of the contaminants.
• The excessive presence of nitrogen, potassium, and phosphorus shows a
negative impact on the degradation of hydrocarbons.
• The rate of bioremediation can also be determined by knowing the
accessibility of organic matters towards microorganisms; which is known as
bioavailability.
10. 3. MOISTURE CONTENT
• Moisture is a very important variable relative to bioremediation.
• Moisture content of soil alters the bioavailability of contaminants, the
transfer of gases, the effective toxicity level of contaminants, the
movement and growth stage of microorganisms, and species
distribution.
• During bioremediation, if the water content is too high, it will be difficult for
atmospheric oxygen to penetrate the soil, and this can be a factor of limiting
growth efficiency and determine the types of organisms that can flourish.
11. • Water availability is defined by biologists in terms of a parameter called
water activity (aw).
• In simple terms, water activity is the ratio of the system‘s vapor pressure to
that of pure water (at the same temperature).
12. 4. TEMPERATURE
• Microbial metabolism is substantially affected by temperature .
• Most microorganisms grows well in the range of 10 to 38°C.
• Technically it is extremely difficult to control the temperature of in-situ processes,
and the temperature of ex-situ processes can only be moderately influenced,
sometimes with great expense.
• The degradation of the contaminants is also affected by temperature especially in
the case of hydrocarbons under both in situ and ex-situ conditions.
• It has been found that a higher temperature of 30°C-40°c increases the
bioremediation in the soil as well as in the marine environment.
13. 5. PH
• Optimum pH is required for the bioremediation process which ranges from 6-
8.
• Neutral pH is suitable for the degradation of petroleum hydrocarbons
whereas some fungi and acidophilic microbes degrade contaminants in an
acidic environment.
• The pH is influenced by a complex relationship between organisms,
contaminant chemistry, and physical and chemical properties of the local
environment.
14. 6. OXYGEN
• In the most of applications, bioremediation is an oxidation process.
• Oxygen is a very important factor to determine the extent and rate of
biodegradation of contaminants.
• Aerobic biodegradation is much faster than anaerobic biodegradation.
• For the aerobic respiratory breakdown of organic contaminants, oxygen
availability plays a significant role.
• In the majority of cases, the addition of hydrogen peroxide is used to
introduce oxygen.
• Hydrogen peroxide is about seven times more soluble in water than oxygen.
15. 7. METAL IONS
• Although some metals are essential in trace quantities for microbial
growth, heavily contaminated sites with high concentrations of metal
ions in contaminated soil or water usually inhibit the metabolic
activity of the cells, thus affecting directly any bioremediation process
16. 8. REDOX POTENTIAL
• The Redox potential is also called oxidation-reduction potential.
• Redox potentials are difficult to be measured in the soil or groundwater and are
not widely used in the field.
• The redox potential of the soil is directly related to the concentration of O2
in the gas and liquid phases.
• The O2 concentration is a function of the rate of gas exchange with the
atmosphere, and the rate of respiration by soil microorganisms and plant roots.
Respiration may deplete O2, lowering the redox potential and creating
anaerobic (i.e., reducing) conditions.
17. • These conditions will restrict aerobic reactions and may encourage
anaerobic processes such as denitrification, sulfate reduction, and
fermentation. Reduced forms of polyvalent metal cations are more soluble
(and thus more mobile) than their oxidized forms.
18. 9. BIOGEOCHEMICAL PARAMETERS
• Measurements of various biogeochemical parameters such as dissolved
oxygen (DO), redox potential, CO2, and other parameters such as NH4+,
NO3-, NO2-, SO4 2-, S2-and Fe2+ will give an indication of the existing
(natural or intrinsic) microbial metabolic activity at the site.
19. CONCLUSION
• Bioremediation is a multidisciplinary technology and successful application
requires deep understanding of all the relevant scientific fields and
attenuation processes.
• It seems that now a days we have entered in the most interesting and
intense phase of process development.
• Potentials and limitations of the technology are well documented in many
resources from the web, books and research papers The experience
accumulated over the years is promising to design cost effective successful
remediation projects.
