1.8.5 Phytoremediation of Heavy Metals
Phytoremediation is the process where the plants are involved in cleaning up the
contaminants from soil (Ojuederie and Babalola 2017). To speed up the reaction,
scientists discovered that rhizospheric bacteria helped the plants to uptake the heavy
metals in a faster rate (Kuffner et al. 2008). Flavobacterium, Pseudomonas, Streptomyces, Agromyces and Serratia were observed in rhizosphere regions and reported
to absorb Zn and Cd (Ghasemi et al. 2018). ACC deaminase activity in bacteria can
induce heavy metal stress tolerance in crop plants, and also it enhanced the
phytoextraction and phytoremediation in plants. Rodriguez et al. (2008) isolated
four bacterial strains from Ni-contaminated soil based on ACC deaminase activity.
Endophytic bacteria is also involved in the process of metal stress tolerance in
crop plants. Sheng et al. (2008) identified two heavy metal–resistant bacteria,
namely Pseudomonas fluorescens G10 and Microbacterium sp. G16, from the root
of canola plants which grow in Pb-contaminated areas. The microbes mentioned
above were resistant to heavy metals and improved the growth of canola in pot
experiment. Bioremediation is essential for the detoxification of heavy metal–polluted environments and to prevent the toxic effects from the environment and
organisms (Emenike et al. 2018a, b).
1.9 Mycoremediation
Mycoremediation is the term coined by Stamets. It is a kind of bioremediation using
fungi to digests and eliminate the contaminants from the environments followed by
repair or retain the nutrients in the environments. Mycofilteration is the process to
filter the toxic waste and microbes using fungal mycelia by the secretion of enzymes.
Fungal mycelium secrets several enzymes and acids which break the lignin and
cellulose (Stamets 2005). The Mycorrhizal fungi can secrete a protein called
glomalin that stabilized the aluminium occurred in the soil, when planted with
Gmelina plants (Dudhane et al. 2012). Say et al. (2003) revealed that the following
fungi species are identified as they are involved in the mycoremediation process to
recover the plants from pollution. Aspergillus niger, Aureobasidium pullulans,
Cladosporium resinae, Funalia trogii, Ganoderma lucidum, Penicillium spp.
(Loukidou et al. 2003). Aspergillus fumigates is the suitable strain used to remove
Pb(II) ions from the aquatic solution. AM fungi have the wider mycelia network, and
they release glomalin protein that has the ability to sequester all types of heavy
metals and renders a metal-free environment to the root zone (Gomathy et al.
2018a, b). Glomalin protein released by the AM fungi has the ability to sequester
the metals in their cell wall.
1 Rhizosphere: Niche for Microbial Rejuvenation and Biodegradation of Pollutants
15
Phytoremediation is the process where the plants are involved in cleaning up the
contaminants from soil (Ojuederie and Babalola 2017). To speed up the reaction,
scientists discovered that rhizospheric bacteria helped the plants to uptake the heavy
metals in a faster rate (Kuffner et al. 2008). Flavobacterium, Pseudomonas, Streptomyces, Agromyces and Serratia were observed in rhizosphere regions and reported
to absorb Zn and Cd (Ghasemi et al. 2018). ACC deaminase activity in bacteria can
induce heavy metal stress tolerance in crop plants, and also it enhanced the
phytoextraction and phytoremediation in plants. Rodriguez et al. (2008) isolated
four bacterial strains from Ni-contaminated soil based on ACC deaminase activity.
Endophytic bacteria is also involved in the process of metal stress tolerance in
crop plants. Sheng et al. (2008) identified two heavy metal–resistant bacteria,
namely Pseudomonas fluorescens G10 and Microbacterium sp. G16, from the root
of canola plants which grow in Pb-contaminated areas. The microbes mentioned
above were resistant to heavy metals and improved the growth of canola in pot
experiment. Bioremediation is essential for the detoxification of heavy metal–polluted environments and to prevent the toxic effects from the environment and
organisms (Emenike et al. 2018a, b).
1.9 Mycoremediation
Mycoremediation is the term coined by Stamets. It is a kind of bioremediation using
fungi to digests and eliminate the contaminants from the environments followed by
repair or retain the nutrients in the environments. Mycofilteration is the process to
filter the toxic waste and microbes using fungal mycelia by the secretion of enzymes.
Fungal mycelium secrets several enzymes and acids which break the lignin and
cellulose (Stamets 2005). The Mycorrhizal fungi can secrete a protein called
glomalin that stabilized the aluminium occurred in the soil, when planted with
Gmelina plants (Dudhane et al. 2012). Say et al. (2003) revealed that the following
fungi species are identified as they are involved in the mycoremediation process to
recover the plants from pollution. Aspergillus niger, Aureobasidium pullulans,
Cladosporium resinae, Funalia trogii, Ganoderma lucidum, Penicillium spp.
(Loukidou et al. 2003). Aspergillus fumigates is the suitable strain used to remove
Pb(II) ions from the aquatic solution. AM fungi have the wider mycelia network, and
they release glomalin protein that has the ability to sequester all types of heavy
metals and renders a metal-free environment to the root zone (Gomathy et al.
2018a, b). Glomalin protein released by the AM fungi has the ability to sequester
the metals in their cell wall.
1 Rhizosphere: Niche for Microbial Rejuvenation and Biodegradation of Pollutants
15