Hence, extremophilic microorganisms can play an important role in the bioremediation of these habitats (Khemili-Talbi et al. 2015). Extremophiles have been utilized
for the microbial degradation of crude oil and refined petroleum pollutants. The
polluting agents can be biodegraded by marine microbes producing extremozymes
which are able to catalyse the oxidation of medium-length alkanes. Several microorganisms have been isolated from marine environments as producers of alkane
degrading enzymes. Park and Park (2018) described the bioremediation of organic
pollutants involving the strategies for alkane degradation under extreme conditions
such as low and high temperature, high salt and acidic and anaerobic conditions.
Alkane degraders seem to possess exclusive metabolic pathway and survival strategies. Hydrocarbons can be mineralized or transformed through the biodegradation
process that occurs in various extreme habitats (Park and Park 2018). Extremophilic
microorganisms from Archaea domain from extreme environments have been found
as potential resources for the bioremediation of hydrocarbons (Giovanlla et al.
2020). Most bacteria that are capable of degrading petroleum hydrocarbons have
been isolated from deep ocean environments. The bacterial species Bacillus safensis
(CFA-06) isolated from petroleum in Campos Basin in Brazil produces two oxidoreductases, namely a catalase and a new oxidoreductase. Theses enzymes have
promising application for petroleum removal because of actively involving in
degradation of aromatic hydrocarbons (da Fonseca et al. 2015).
A recent review has focussed on the bioremediation of aromatic compounds such
as toluene and xylenes involving the degradation of such pollutants (Blazquez et al.
2018). The degradation of aromatic compounds is another key issue in bioremediation of oil contaminated sites. Nocardioides species strain KP7 has been isolated
from a Kuwait beach, which produces a dioxygenase enzyme that is able to degrade
phenanthrene (Saito et al. 2000). Numerous marine species have been identified as
producers of enzymes catalysing the degradation of halogenated compounds. For
example, the marine bacteria Paracoccus sp. DEH99 (Zhang et al. 2014) and
Pseudomonas stutzeri DEH130 (Zhang et al. 2013) have been isolated which
produce exosomes-haloacid dehalogenases that are able to catalyse the
de-halogenation of 2-alanoic acids. The bacterium Psychromonas ingrahamii isolated from the sea ice interface, produces a haloacid dehalogenase which degrades
chlorinated and brominated short chain (less than C3) haloacids (Nikolaivits et al.
2017; Novak et al. 2013). Yakimov et al. (1999) isolated the Alcanivorax group from
the North Sea as biosurfactant-producing and alkane-degrading marine bacteria.
These bacterial strains were isolated from a variety of marine environments such
as oil spill contaminated sites. Genus Alcanivorax has been found to play a major
role in the first step of crude oil biodegradation in the marine environment and
observed that these bacteria are important for the biodegradation of petroleum
especially under bioremediation conditions (Harayama et al. 1999). Al-Maghrabi
et al. (1999) reported rapid degradation of crude oil using thermophilic bacteria and
was found to survive in saline environments. Oil spills have been successfully
bioremediated in marine, Arctic and Antarctic environments (Delille et al. 1998;
Margesin and Schinner 1999). Kuznetsov et al. (1992) found a halo- and
thermotolerant Streptomyces albaxialis which degraded crude oil and petroleum
308
S. Kaushik et al.
for the microbial degradation of crude oil and refined petroleum pollutants. The
polluting agents can be biodegraded by marine microbes producing extremozymes
which are able to catalyse the oxidation of medium-length alkanes. Several microorganisms have been isolated from marine environments as producers of alkane
degrading enzymes. Park and Park (2018) described the bioremediation of organic
pollutants involving the strategies for alkane degradation under extreme conditions
such as low and high temperature, high salt and acidic and anaerobic conditions.
Alkane degraders seem to possess exclusive metabolic pathway and survival strategies. Hydrocarbons can be mineralized or transformed through the biodegradation
process that occurs in various extreme habitats (Park and Park 2018). Extremophilic
microorganisms from Archaea domain from extreme environments have been found
as potential resources for the bioremediation of hydrocarbons (Giovanlla et al.
2020). Most bacteria that are capable of degrading petroleum hydrocarbons have
been isolated from deep ocean environments. The bacterial species Bacillus safensis
(CFA-06) isolated from petroleum in Campos Basin in Brazil produces two oxidoreductases, namely a catalase and a new oxidoreductase. Theses enzymes have
promising application for petroleum removal because of actively involving in
degradation of aromatic hydrocarbons (da Fonseca et al. 2015).
A recent review has focussed on the bioremediation of aromatic compounds such
as toluene and xylenes involving the degradation of such pollutants (Blazquez et al.
2018). The degradation of aromatic compounds is another key issue in bioremediation of oil contaminated sites. Nocardioides species strain KP7 has been isolated
from a Kuwait beach, which produces a dioxygenase enzyme that is able to degrade
phenanthrene (Saito et al. 2000). Numerous marine species have been identified as
producers of enzymes catalysing the degradation of halogenated compounds. For
example, the marine bacteria Paracoccus sp. DEH99 (Zhang et al. 2014) and
Pseudomonas stutzeri DEH130 (Zhang et al. 2013) have been isolated which
produce exosomes-haloacid dehalogenases that are able to catalyse the
de-halogenation of 2-alanoic acids. The bacterium Psychromonas ingrahamii isolated from the sea ice interface, produces a haloacid dehalogenase which degrades
chlorinated and brominated short chain (less than C3) haloacids (Nikolaivits et al.
2017; Novak et al. 2013). Yakimov et al. (1999) isolated the Alcanivorax group from
the North Sea as biosurfactant-producing and alkane-degrading marine bacteria.
These bacterial strains were isolated from a variety of marine environments such
as oil spill contaminated sites. Genus Alcanivorax has been found to play a major
role in the first step of crude oil biodegradation in the marine environment and
observed that these bacteria are important for the biodegradation of petroleum
especially under bioremediation conditions (Harayama et al. 1999). Al-Maghrabi
et al. (1999) reported rapid degradation of crude oil using thermophilic bacteria and
was found to survive in saline environments. Oil spills have been successfully
bioremediated in marine, Arctic and Antarctic environments (Delille et al. 1998;
Margesin and Schinner 1999). Kuznetsov et al. (1992) found a halo- and
thermotolerant Streptomyces albaxialis which degraded crude oil and petroleum
308
S. Kaushik et al.