Sequential and combined actions are required for such treatment successively by
several groups of microorganisms such as phosphate-accumulating organism and
heterotrophic bacteria or microbes which are able to perform nitrification, denitrification or anammox (Gieseke et al. 2001). The extremophiles which can degrade
ammonia are now one of the main candidates for wastewater treatment in addition to
other natural various types of microorganisms. Other contaminants such as sulphur,
manganese, iron and runoff pollutants (hydrocarbons, fertilizers) can also be
removed. As the industrial effluents have high salt environments along with other
organic compounds and heavy metals, polyextremophilic microorganisms having a
higher resistance to metals, complex dyes along with high salt concentration can be
used for industrial and other similar wastewater treatment. Such polyextremophilic
microbes can be identified and isolated from industrial effluent or waste sites.
Wastewater and industrial effluent is a complex mixture of dyes, metals along with
other organic compounds and high salt substances. Some industrial effluent may be
highly acidic or highly basic.
Bioremediation using living microorganisms particularly halophiles can offer an
efficient and cheap option for decontamination of wastewater. In recent years,
haloarchaea have been assessed successfully for bioremediation and biotechnological applications (Arora et al. 2012; Oren 2010; Bonete and Martínez-Espinosa
2011) because of extraordinary properties of their enzymes like high thermostability
and resistance to denaturing agents such as detergents, extreme pH and organic
solvents (Castillo et al. 2005). Activity and maintenance of the stable conformation
of the enzymes at high salt concentrations are due to the presence of acidic amino
acids in these proteins (Oren 2008). Most of the species from Haloferacease and
Halobacteriaceae families can grow under anaerobic conditions in diverse conditions of salt concentrations (Torregrosa-Crespo et al. 2016; Valentine 2007). Consequently, these microorganisms might be applied for bioremediation in saline and
hypersaline wastewater treatments because of their high tolerance to salt, metals and
organic pollutants (Bonete et al. 2015; Najera-Fernandez et al. 2012; TorregrosaCrespo et al. 2016).
Recently, more efforts have been devoted to effectively utilizing high-strength
organic wastes by using extremophilic microorganisms. The utilization of highstrength wastes involves major issues, including sludge foaming, the inhibition of
key microorganisms of anaerobic digestion such as methanogens, and slower hydrolysis of complex compounds such as long-chain fatty acids and lignin. Hence,
extremophilic microorganisms able to deal with these compounds have become of
great interest in designing new strategies to treat wastewater. Recent researches
suggest that growth and activity of extremophiles were significant in the treatment
of activated sludge and wastewater (DeLong 1998; Casamayor et al. 2000; Schramm
et al. 1999). The roles of methanogenic extremophilic archaea within a broad range
of activated sludge, submerged biofilters and membrane bioreactors have been
studied in recent research (Gomez-Silvan et al. 2010; Gray et al. 2002; Damgaard
et al. 2001). Under oxic conditions, no methanogenesis was detected, but once
oxygen is depleted, methane production ensued. The results suggest that
methanogenic archaea can be activated under anoxic conditions (Gray et al. 2002).
12 Potential of Extremophiles for Bioremediation
317
several groups of microorganisms such as phosphate-accumulating organism and
heterotrophic bacteria or microbes which are able to perform nitrification, denitrification or anammox (Gieseke et al. 2001). The extremophiles which can degrade
ammonia are now one of the main candidates for wastewater treatment in addition to
other natural various types of microorganisms. Other contaminants such as sulphur,
manganese, iron and runoff pollutants (hydrocarbons, fertilizers) can also be
removed. As the industrial effluents have high salt environments along with other
organic compounds and heavy metals, polyextremophilic microorganisms having a
higher resistance to metals, complex dyes along with high salt concentration can be
used for industrial and other similar wastewater treatment. Such polyextremophilic
microbes can be identified and isolated from industrial effluent or waste sites.
Wastewater and industrial effluent is a complex mixture of dyes, metals along with
other organic compounds and high salt substances. Some industrial effluent may be
highly acidic or highly basic.
Bioremediation using living microorganisms particularly halophiles can offer an
efficient and cheap option for decontamination of wastewater. In recent years,
haloarchaea have been assessed successfully for bioremediation and biotechnological applications (Arora et al. 2012; Oren 2010; Bonete and Martínez-Espinosa
2011) because of extraordinary properties of their enzymes like high thermostability
and resistance to denaturing agents such as detergents, extreme pH and organic
solvents (Castillo et al. 2005). Activity and maintenance of the stable conformation
of the enzymes at high salt concentrations are due to the presence of acidic amino
acids in these proteins (Oren 2008). Most of the species from Haloferacease and
Halobacteriaceae families can grow under anaerobic conditions in diverse conditions of salt concentrations (Torregrosa-Crespo et al. 2016; Valentine 2007). Consequently, these microorganisms might be applied for bioremediation in saline and
hypersaline wastewater treatments because of their high tolerance to salt, metals and
organic pollutants (Bonete et al. 2015; Najera-Fernandez et al. 2012; TorregrosaCrespo et al. 2016).
Recently, more efforts have been devoted to effectively utilizing high-strength
organic wastes by using extremophilic microorganisms. The utilization of highstrength wastes involves major issues, including sludge foaming, the inhibition of
key microorganisms of anaerobic digestion such as methanogens, and slower hydrolysis of complex compounds such as long-chain fatty acids and lignin. Hence,
extremophilic microorganisms able to deal with these compounds have become of
great interest in designing new strategies to treat wastewater. Recent researches
suggest that growth and activity of extremophiles were significant in the treatment
of activated sludge and wastewater (DeLong 1998; Casamayor et al. 2000; Schramm
et al. 1999). The roles of methanogenic extremophilic archaea within a broad range
of activated sludge, submerged biofilters and membrane bioreactors have been
studied in recent research (Gomez-Silvan et al. 2010; Gray et al. 2002; Damgaard
et al. 2001). Under oxic conditions, no methanogenesis was detected, but once
oxygen is depleted, methane production ensued. The results suggest that
methanogenic archaea can be activated under anoxic conditions (Gray et al. 2002).
12 Potential of Extremophiles for Bioremediation
317