degradation products, a phosphodiester and an alcohol, are produced by the hydrolysis process through the phosphotriesterase activity of this enzyme on the organophosphorus pesticides. This ScoPox enzyme being its extremophilic origin is robust,
i.e. resistance to detergents and solvents (Merone et al. 2005) and activity over a
wide range of temperature and long-term storage (Remy et al. 2016). The enzyme
could be used in filtration devices to treat effluent materials with organophosphorus
compounds as it can be immobilized easily. Poirier et al. (2017) reported a variant
ScoPox-αD6 by engineering ScoPox with enhanced phosphotriesterase activity.
12.5.3 Bioremediation of Heavy Metals
Technological advancement and industrialization have put a mounting burden on the
environment by releasing large quantities of perilous waste, heavy metals (e.g.,
chromium, cadmium, lead) and metalloids (e.g., arsenic and antimony). The buildup of heavy metals and metalloids in soil and waters continues to cause serious
health concerns worldwide, as these metals and metalloids cannot be degraded into
non-toxic forms, but persist in the ecosystem (Ayangbenro and Babalola 2017).
Some metals such as iron, zinc, manganese, copper, cobalt and molybdenum are
trace elements necessary for life and required at a certain level. They are functioning
as co-factors for some enzymes, regulators of osmotic pressure, micronutrients and
stabilization of molecules. They are toxic when generated in excess and depend on
the availability and absorbed dose (Rasmussen et al. 2000).
Heavy metals such as arsenic, lead, mercury, aluminium and cadmium are toxic
to organisms. The presence of heavy metals in the environment has been a major
concern because of their toxicity. The toxicity of heavy metals is related to exposure
dose and the metallic chemical species, responsible for bioavailability and mobility
in the organism and in the environment. The most soluble and bioavailable metallic
species present the highest toxicity, risks to human health and impacts on ecosystems (de Paiva et al. 2015; Ospina-Alvarez et al. 2014). Exposure to heavy metals
has been linked with teratogenicity, mutagenicity, cancer, neurological, circulatory,
endocrine and immune system disorders (Kim et al. 2015; Korashy et al. 2017).
Heavy metal toxicity is demonstrated in their ability to disrupt enzyme structures and
functions by binding with thiol and protein groups, or by replacing co-factors in
prosthetic groups of enzymes. Exposure to mercury (Hg) and lead (Pb) can cause the
development of autoimmunity, leading to joint disease such as rheumatoid arthritis,
nervous and circulatory disorders and kidney diseases (Ayangbenro and Babalola
2017). Cadmium (Cd) is known to be mutagenic and carcinogenic. Chromium
(Cr) causes nausea, diarrhoea, headaches, hair loss and vomiting in humans.
Heavy metals such as Cd, Pb, Hg and Al can exert their toxicity by interacting
metabolically with nutritionally essential elements such as Ca and Fe, interfering
with vital physiologically functions (Goyer 1997). Arsenic, mercury, lead and
chromium may cause oxidative stress due to the production of reactive oxygen
species (ROS) (Pinto et al. 2003).
12 Potential of Extremophiles for Bioremediation
311
i.e. resistance to detergents and solvents (Merone et al. 2005) and activity over a
wide range of temperature and long-term storage (Remy et al. 2016). The enzyme
could be used in filtration devices to treat effluent materials with organophosphorus
compounds as it can be immobilized easily. Poirier et al. (2017) reported a variant
ScoPox-αD6 by engineering ScoPox with enhanced phosphotriesterase activity.
12.5.3 Bioremediation of Heavy Metals
Technological advancement and industrialization have put a mounting burden on the
environment by releasing large quantities of perilous waste, heavy metals (e.g.,
chromium, cadmium, lead) and metalloids (e.g., arsenic and antimony). The buildup of heavy metals and metalloids in soil and waters continues to cause serious
health concerns worldwide, as these metals and metalloids cannot be degraded into
non-toxic forms, but persist in the ecosystem (Ayangbenro and Babalola 2017).
Some metals such as iron, zinc, manganese, copper, cobalt and molybdenum are
trace elements necessary for life and required at a certain level. They are functioning
as co-factors for some enzymes, regulators of osmotic pressure, micronutrients and
stabilization of molecules. They are toxic when generated in excess and depend on
the availability and absorbed dose (Rasmussen et al. 2000).
Heavy metals such as arsenic, lead, mercury, aluminium and cadmium are toxic
to organisms. The presence of heavy metals in the environment has been a major
concern because of their toxicity. The toxicity of heavy metals is related to exposure
dose and the metallic chemical species, responsible for bioavailability and mobility
in the organism and in the environment. The most soluble and bioavailable metallic
species present the highest toxicity, risks to human health and impacts on ecosystems (de Paiva et al. 2015; Ospina-Alvarez et al. 2014). Exposure to heavy metals
has been linked with teratogenicity, mutagenicity, cancer, neurological, circulatory,
endocrine and immune system disorders (Kim et al. 2015; Korashy et al. 2017).
Heavy metal toxicity is demonstrated in their ability to disrupt enzyme structures and
functions by binding with thiol and protein groups, or by replacing co-factors in
prosthetic groups of enzymes. Exposure to mercury (Hg) and lead (Pb) can cause the
development of autoimmunity, leading to joint disease such as rheumatoid arthritis,
nervous and circulatory disorders and kidney diseases (Ayangbenro and Babalola
2017). Cadmium (Cd) is known to be mutagenic and carcinogenic. Chromium
(Cr) causes nausea, diarrhoea, headaches, hair loss and vomiting in humans.
Heavy metals such as Cd, Pb, Hg and Al can exert their toxicity by interacting
metabolically with nutritionally essential elements such as Ca and Fe, interfering
with vital physiologically functions (Goyer 1997). Arsenic, mercury, lead and
chromium may cause oxidative stress due to the production of reactive oxygen
species (ROS) (Pinto et al. 2003).
12 Potential of Extremophiles for Bioremediation
311