24.4.1 Use of GMO in Bioremediation (Introduction into
the Environment)
24.4.1.1 Genetically Modified Microorganisms
A number of studies have been conducted on the bacterial metabolism of engineered
microorganisms, e.g., Escherichia coli. However, for real-world bioremediation
application, the strains that were isolated from the exact contaminated location are
considered being more suitable, with a higher likelihood of long-term survival (Lan
et al. 2006).
Natural bioremediation processes promoted by microorganisms, e.g., metal
reduction, complexation, precipitation, and promotion of the plant growth on the
contaminated site (phytoremediation) can be further improved by genetic engineering. For example, Pichia pastoris plants were genetically engineered to overexpress
a metal-resistant variant of cytochrome b5 reductase to provide a high-throughput
bioaccumulation and biotransformation of silver and selenium. Their ions were
enzymatically reduced to form stable 70–180 nm elemental nanoparticles. These
nanoparticles exhibited at least a tenfold lower cytotoxicity toward HDF,
EPG85–257, and T47D cells than silver nitrate and selenium dioxide (Elahian
et al. 2017).
Multipurpose approaches can be enabled by enhanced engineering. For example,
a cadmium-resistant bacterium Pseudomonas aeruginosa was isolated from a
Cd-contaminated oil field and further engineered to overexpress targeting
metallothioneins on the cell surface to immobilize Cd
2+ . Introduction of engineered
bacteria with improved cadmium tolerance and accumulation enabled the growth
promotion of green peas, Pisum sativum L., significantly elevating the shoot and root
biomass production and leaf chlorophyll content (Huang et al. 2016). Pseudomonas
putida X3 was engineered by introducing methyl parathion (MP)-degrading gene to
obtain the ability to degrade methyl parathion. The application of Pseudomonas
putida X3 into Cd-contaminated soil reduced the amount of bioavailable Cd by its
conversion into a less soluble/exchangeable form and organic-bound Cd (Zhang
et al. 2016a).
Enhanced bioremediation of pesticides and chlorinated organic compounds is a
common target of genetic engineering. Yang et al. (2010) genetically engineered a
native soil bacterium Stenotrophomonas sp. strain YC-1 producing methyl parathion
hydrolase by a surface anchor system derived from the truncated ice nucleation
protein from Pseudomonas syringae to possess a broader substrate specificity
combined with an enhanced degradation rate of organophosphates. As a result, a
mixture of six organophosphate pesticides was completely degraded within 5 h.
514
M. Halecký and E. Kozliak
the Environment)
24.4.1.1 Genetically Modified Microorganisms
A number of studies have been conducted on the bacterial metabolism of engineered
microorganisms, e.g., Escherichia coli. However, for real-world bioremediation
application, the strains that were isolated from the exact contaminated location are
considered being more suitable, with a higher likelihood of long-term survival (Lan
et al. 2006).
Natural bioremediation processes promoted by microorganisms, e.g., metal
reduction, complexation, precipitation, and promotion of the plant growth on the
contaminated site (phytoremediation) can be further improved by genetic engineering. For example, Pichia pastoris plants were genetically engineered to overexpress
a metal-resistant variant of cytochrome b5 reductase to provide a high-throughput
bioaccumulation and biotransformation of silver and selenium. Their ions were
enzymatically reduced to form stable 70–180 nm elemental nanoparticles. These
nanoparticles exhibited at least a tenfold lower cytotoxicity toward HDF,
EPG85–257, and T47D cells than silver nitrate and selenium dioxide (Elahian
et al. 2017).
Multipurpose approaches can be enabled by enhanced engineering. For example,
a cadmium-resistant bacterium Pseudomonas aeruginosa was isolated from a
Cd-contaminated oil field and further engineered to overexpress targeting
metallothioneins on the cell surface to immobilize Cd
2+ . Introduction of engineered
bacteria with improved cadmium tolerance and accumulation enabled the growth
promotion of green peas, Pisum sativum L., significantly elevating the shoot and root
biomass production and leaf chlorophyll content (Huang et al. 2016). Pseudomonas
putida X3 was engineered by introducing methyl parathion (MP)-degrading gene to
obtain the ability to degrade methyl parathion. The application of Pseudomonas
putida X3 into Cd-contaminated soil reduced the amount of bioavailable Cd by its
conversion into a less soluble/exchangeable form and organic-bound Cd (Zhang
et al. 2016a).
Enhanced bioremediation of pesticides and chlorinated organic compounds is a
common target of genetic engineering. Yang et al. (2010) genetically engineered a
native soil bacterium Stenotrophomonas sp. strain YC-1 producing methyl parathion
hydrolase by a surface anchor system derived from the truncated ice nucleation
protein from Pseudomonas syringae to possess a broader substrate specificity
combined with an enhanced degradation rate of organophosphates. As a result, a
mixture of six organophosphate pesticides was completely degraded within 5 h.
514
M. Halecký and E. Kozliak