range of environments including deserts, salaras, ice fields, geothermal springs and
diverse zones in Chile such as Atacama Desert, Altiplano, Central Chile, Patagonia
and Antarctica has discussed the molecular and physiological capabilities of many of
these isolates which has great potential for bioremediation processes (Orellana et al.
2018).
12.5.1 Bioremediation of Petroleum Products
Petroleum is composed of hundreds or thousands of aliphatic, branched and aromatic
hydrocarbons (Prince 1993) and other organic compounds including organometallic
constituents (Butler and Mason 1997). As the petroleum is an important energy
source in daily life and industry, its annual consumption has been increasing in the
last several decades. Many activities such as municipal and industrial runoff, effluent
release, offshore and onshore petroleum industry activities as well as accidental
spills cause petroleum hydrocarbon pollution which are toxic to animals, vegetation
and humans. These hydrocarbon pollutants which cause adverse impact on human
health and environment are classified as priority environmental pollutants by the US
Environmental Protection Agency (1986). These hydrocarbon pollutants through
spillages and leakage from underground tanks, steamers, abandoned oil refinery sites
or unplugging of oil wells cause contamination of surface soil, groundwater and
ocean (Souza et al. 2014; Prince et al. 2013).
Hydrocarbon pollutants comprising petroleum and its derivatives (refined products), which are released into the environment by oil spills and polycyclic aromatic
hydrocarbons (PAHs) are found in a wide range of habitats and affect the health of
many organisms (Giovanlla et al. 2020). Various hydrocarbons have different
susceptibilities to microbial attack. Degradation is more difficult in compound
with complex chemical structures, e.g. polycyclic hydrocarbons (Fathepure 2014).
PAHs and halogenated hydrocarbons can be remediated with microorganisms
(Prasad 2016). PAHs are a class of chemical compounds of two or more benzene
rings fused in a linear, angular or cluster arrangement. They may be classified as high
molecular weight (HMW) or low molecular weight (LMW). Petroleum derivatives
such as PAHs having a great affinity for macromolecules such as DNA, RNA and
proteins can induce mutations, leading to develop tumours in the skin and other
organs (Varjani et al. 2017). As PAHs are known for their toxicity and carcinogenicity, they are recognized globally as priority pollutants (Prasad 2016).
The application of bioremediation for petroleum products is becoming the technique of choice for environmental researchers. Biodegradation of petroleum hydrocarbons varies with the chemical structure and molecular weight of hydrocarbon
molecules. The chemical structure of organic pollutants has significant influence on
the extent and rate of their biodegradation (Alexander 1981). Presently, a majority of
commercial applications of bioremediation depend upon indigenous microorganisms, and most are employed for hydrocarbon-contaminated sites. Bioremediation of
extreme environments requires extremophiles that are adapted to these habitats.
12 Potential of Extremophiles for Bioremediation
307
diverse zones in Chile such as Atacama Desert, Altiplano, Central Chile, Patagonia
and Antarctica has discussed the molecular and physiological capabilities of many of
these isolates which has great potential for bioremediation processes (Orellana et al.
2018).
12.5.1 Bioremediation of Petroleum Products
Petroleum is composed of hundreds or thousands of aliphatic, branched and aromatic
hydrocarbons (Prince 1993) and other organic compounds including organometallic
constituents (Butler and Mason 1997). As the petroleum is an important energy
source in daily life and industry, its annual consumption has been increasing in the
last several decades. Many activities such as municipal and industrial runoff, effluent
release, offshore and onshore petroleum industry activities as well as accidental
spills cause petroleum hydrocarbon pollution which are toxic to animals, vegetation
and humans. These hydrocarbon pollutants which cause adverse impact on human
health and environment are classified as priority environmental pollutants by the US
Environmental Protection Agency (1986). These hydrocarbon pollutants through
spillages and leakage from underground tanks, steamers, abandoned oil refinery sites
or unplugging of oil wells cause contamination of surface soil, groundwater and
ocean (Souza et al. 2014; Prince et al. 2013).
Hydrocarbon pollutants comprising petroleum and its derivatives (refined products), which are released into the environment by oil spills and polycyclic aromatic
hydrocarbons (PAHs) are found in a wide range of habitats and affect the health of
many organisms (Giovanlla et al. 2020). Various hydrocarbons have different
susceptibilities to microbial attack. Degradation is more difficult in compound
with complex chemical structures, e.g. polycyclic hydrocarbons (Fathepure 2014).
PAHs and halogenated hydrocarbons can be remediated with microorganisms
(Prasad 2016). PAHs are a class of chemical compounds of two or more benzene
rings fused in a linear, angular or cluster arrangement. They may be classified as high
molecular weight (HMW) or low molecular weight (LMW). Petroleum derivatives
such as PAHs having a great affinity for macromolecules such as DNA, RNA and
proteins can induce mutations, leading to develop tumours in the skin and other
organs (Varjani et al. 2017). As PAHs are known for their toxicity and carcinogenicity, they are recognized globally as priority pollutants (Prasad 2016).
The application of bioremediation for petroleum products is becoming the technique of choice for environmental researchers. Biodegradation of petroleum hydrocarbons varies with the chemical structure and molecular weight of hydrocarbon
molecules. The chemical structure of organic pollutants has significant influence on
the extent and rate of their biodegradation (Alexander 1981). Presently, a majority of
commercial applications of bioremediation depend upon indigenous microorganisms, and most are employed for hydrocarbon-contaminated sites. Bioremediation of
extreme environments requires extremophiles that are adapted to these habitats.
12 Potential of Extremophiles for Bioremediation
307