have focused on the physiology, enzymology, ecology, taxonomy, molecular biology and genetics. These microorganisms have made adaptations in their genetic and
metabolic machinery to flourish in the harsh conditions These microorganisms are
good candidates for research in different fields of science including bioremediation
and biotechnology due to their ability to grow under a wide range of extreme
conditions (Xu and Zhou 2016; Najera-Fernandez et al. 2012; Arora et al. 2014).
Studies on extremophiles have progressed to the extent that there are dedicated
scientific journal such as ‘Archae’ and ‘Extremophiles’ as well as regular international ‘extremophile’ symposia and conferences are organized. There are a number
of variables that can lead to environments being considered extreme such as temperature, pH, salinity, heavy metals or radiations. Some extremophiles have adapted
to a number of factors such as the alkaline pH and high salinity (Tindall et al. 1984),
pressure and temperature, i.e. near deep-sea hydrothermal vents (Pettit 2011).
Extremophiles have been isolated in diverse zones that possess extreme conditions,
and the products obtainable from these extremophiles such as enzymes, proteins and
compatible solutes are of great interest to biotechnology, industry and environmental
issues.
A worldwide environmental problem has occurred over the past few decades
because of the rapid increase in urbanization and industrialization. Environmental
pollution is a very big problem today due to hazardous waste leading to scarcity of
clean water and disturbance of soil causing decrease in crop production and human
health. Bioremediation have many advantages to remediate polluted sites from
economic, environmental and practical aspects. The main remediation processes
that can be mediated by the action of microorganisms include adsorption and
biodegradation of organic contaminants and the immobilization, mobilization
and/or transformation of contaminants especially heavy metals. In these processes,
microorganisms are stimulated to rapidly degrade hazardous organic pollutants to
environmentally safe levels in water and soil. Hence, bioremediation is considered
one of the safer, cleaner, cost-effective and eco-friendly technology for
decontaminating sites which are contaminated with wide range of pollutants. The
most recent research on extremophiles surviving in a wide range of extreme hostile
environments has demonstrated the beneficial for bioremediation processes. The
remarkable adaptation capabilities of extremophiles convert them into an attractive
source of biocatalyst or extremozymes for bioremediation. This review is focussed
on the extremophilic microorganisms and their potential applications in
bioremediation.
12.2 Extremophilic Microorganisms and Their Diversity
An extremophile is an organism which thrives in or requires “extreme” conditions,
i.e. adapted to survive in diverse ecological niches. These conditions can refer to
geochemical and physical extremes such as salinity, pH, pressure, temperature,
radiation, presence of toxic compounds and water availability. Thus, extremophiles
12 Potential of Extremophiles for Bioremediation
297
metabolic machinery to flourish in the harsh conditions These microorganisms are
good candidates for research in different fields of science including bioremediation
and biotechnology due to their ability to grow under a wide range of extreme
conditions (Xu and Zhou 2016; Najera-Fernandez et al. 2012; Arora et al. 2014).
Studies on extremophiles have progressed to the extent that there are dedicated
scientific journal such as ‘Archae’ and ‘Extremophiles’ as well as regular international ‘extremophile’ symposia and conferences are organized. There are a number
of variables that can lead to environments being considered extreme such as temperature, pH, salinity, heavy metals or radiations. Some extremophiles have adapted
to a number of factors such as the alkaline pH and high salinity (Tindall et al. 1984),
pressure and temperature, i.e. near deep-sea hydrothermal vents (Pettit 2011).
Extremophiles have been isolated in diverse zones that possess extreme conditions,
and the products obtainable from these extremophiles such as enzymes, proteins and
compatible solutes are of great interest to biotechnology, industry and environmental
issues.
A worldwide environmental problem has occurred over the past few decades
because of the rapid increase in urbanization and industrialization. Environmental
pollution is a very big problem today due to hazardous waste leading to scarcity of
clean water and disturbance of soil causing decrease in crop production and human
health. Bioremediation have many advantages to remediate polluted sites from
economic, environmental and practical aspects. The main remediation processes
that can be mediated by the action of microorganisms include adsorption and
biodegradation of organic contaminants and the immobilization, mobilization
and/or transformation of contaminants especially heavy metals. In these processes,
microorganisms are stimulated to rapidly degrade hazardous organic pollutants to
environmentally safe levels in water and soil. Hence, bioremediation is considered
one of the safer, cleaner, cost-effective and eco-friendly technology for
decontaminating sites which are contaminated with wide range of pollutants. The
most recent research on extremophiles surviving in a wide range of extreme hostile
environments has demonstrated the beneficial for bioremediation processes. The
remarkable adaptation capabilities of extremophiles convert them into an attractive
source of biocatalyst or extremozymes for bioremediation. This review is focussed
on the extremophilic microorganisms and their potential applications in
bioremediation.
12.2 Extremophilic Microorganisms and Their Diversity
An extremophile is an organism which thrives in or requires “extreme” conditions,
i.e. adapted to survive in diverse ecological niches. These conditions can refer to
geochemical and physical extremes such as salinity, pH, pressure, temperature,
radiation, presence of toxic compounds and water availability. Thus, extremophiles
12 Potential of Extremophiles for Bioremediation
297