enzyme is responsible for the hydrolysis of urea fertiliser applied to the soil into NH 3
and CO 2 with the concomitant rise in soil pH.
In earlier studies on plant growth regulators, the activities of rhizosphere bacteria
including nitrogen fixation, production of cytokinin, auxin or hydrolytic enzymes
such protease, lipase, pectinase and amylase increased the N, P and K uptake of plant
components.
1.6 Common Source of Pollutants in Soil
Soil pollution is one of the worldwide problems, which is caused due to the
assimilation of toxic compounds through the discharge of industrial waste into the
soil, salts due the application of pesticides, herbicides and fertilizers, seepage from
landfills, solid waste and radioactive materials affecting plant and animal growth.
The agriculture mainly depends on main factors, namely organic inputs and
inorganic fertilizers and pesticides. Vehicles also release some major sources like
petroleum hydrocarbons, dioxins and polycyclic aromatic hydrocarbons that affect
soil health. Industrial wastes are disposed through the pits and affect the groundwater
supply.
1.7 Biological Degradation of Pollutants
Microorganisms are omnipresent which are distributed widely because they can
easily grow and multiplied, for their nutritional requirements, they can degrade the
pollutants and wastes for their energy. Biodegradation of pollutants are called as
bioremediation. Some microbes convert, modify and finally utilize the toxics for
their survival (Tang et al. 2007).
Instead of collecting pollutants, bioremediation is a process applied to break
down and transform the heavy molecules in to simple things like less toxic or
nontoxic compounds (Strong and Burgess 2008). Different types of biological
processes include bio-attenuation, biostimulation, bioaugmentation, Bioventing,
Biosparging and biopiles.
1.7.1 Principles of Bioremediation
Bioremediation is defined as the process whereby biological organisms are used to
break down hazardous substances into less toxic or nontoxic substances. Microbes in
the environment are much suited for this purpose to destruct the contaminants by the
secretion of several enzymes, namely oxidoreductases, hydrolases, lyases, transferases, isomerases and ligases that convert the pollutants into harmless unpolluted
1 Rhizosphere: Niche for Microbial Rejuvenation and Biodegradation of Pollutants
9
and CO 2 with the concomitant rise in soil pH.
In earlier studies on plant growth regulators, the activities of rhizosphere bacteria
including nitrogen fixation, production of cytokinin, auxin or hydrolytic enzymes
such protease, lipase, pectinase and amylase increased the N, P and K uptake of plant
components.
1.6 Common Source of Pollutants in Soil
Soil pollution is one of the worldwide problems, which is caused due to the
assimilation of toxic compounds through the discharge of industrial waste into the
soil, salts due the application of pesticides, herbicides and fertilizers, seepage from
landfills, solid waste and radioactive materials affecting plant and animal growth.
The agriculture mainly depends on main factors, namely organic inputs and
inorganic fertilizers and pesticides. Vehicles also release some major sources like
petroleum hydrocarbons, dioxins and polycyclic aromatic hydrocarbons that affect
soil health. Industrial wastes are disposed through the pits and affect the groundwater
supply.
1.7 Biological Degradation of Pollutants
Microorganisms are omnipresent which are distributed widely because they can
easily grow and multiplied, for their nutritional requirements, they can degrade the
pollutants and wastes for their energy. Biodegradation of pollutants are called as
bioremediation. Some microbes convert, modify and finally utilize the toxics for
their survival (Tang et al. 2007).
Instead of collecting pollutants, bioremediation is a process applied to break
down and transform the heavy molecules in to simple things like less toxic or
nontoxic compounds (Strong and Burgess 2008). Different types of biological
processes include bio-attenuation, biostimulation, bioaugmentation, Bioventing,
Biosparging and biopiles.
1.7.1 Principles of Bioremediation
Bioremediation is defined as the process whereby biological organisms are used to
break down hazardous substances into less toxic or nontoxic substances. Microbes in
the environment are much suited for this purpose to destruct the contaminants by the
secretion of several enzymes, namely oxidoreductases, hydrolases, lyases, transferases, isomerases and ligases that convert the pollutants into harmless unpolluted
1 Rhizosphere: Niche for Microbial Rejuvenation and Biodegradation of Pollutants
9