et al. 2013; Coelho et al. 2015). In areas where hydrocarbons cause contamination,
heterotrophic genera of bacteria Micrococcus, Mycobacterium, Vibrio, Pseudomonas,
Corynebacterium,
Arthrobacter,
Achromobacter,
Acinetobacter,
Flavobacterium, Brevibacterium and Nocardia are found to be present (Jonsson
and Haller 2014). Among all of them, the best hydrocarbon-biodegrading bacteria
was Bacillus (Joutey et al. 2013). The bacterial strains which are capable to often
remediate aromatic hydrocarbons have been isolated so far, basically from the soil
with bacteria, i.e. Gram-negative, belongs to the genus Pseudomonas (Coelho et al.
2015). Microbes play a significant role in biodegradation of heavy metals which are
most volatile by the process of methylation. For instance, mercury (Hg II) easily
undergoes methylation into gaseous methyl mercury by various bacterial species, for
example, Staphylococcus, P. aeruginosa, Brevibacterium iodonium, Bacillus
pumilus, and Alcaligenes faecalis. Bacteria are capable to leach higher
concentrations of heavy metals such as arsenic, cobalt, copper, cadmium and zinc
from polluted soils, for example, acidophilic iron bacteria like Arthrobacter spp.,
Acidithiobacillus ferrooxidans, Pseudomonas veronii, Kocuria flava, Sporosarcina
ginsengisoli, Bacillus cereus, sulphur-oxidizing bacteria and Burkholderia spp. by
the process of methylation and redox reactions (Mateos et al. 2006; Joutey et al.
2013; Coelho et al. 2015). Detoxification-based, especially arsenic (V), reduction
has been best studied in E. coli (Mateos et al. 2006). Many catabolic plasmids had
been discovered in the species such as Alcaligenes, Arthrobacter, Flavobacterium,
Actinobacter, Moraxella, Klebsiella and Pseudomonas (Sayler and Ripp 2000). A
wide range of bacteria metabolize pesticides such as genera Alcaligenes,
Flavobacterium, Pseudomonas and Rhodococcus (Nawaz et al. 2011). Bacterial
species that belong to genera Bacillus, Cellulomonas, Acinetobacter, Pseudomonas,
Rhodoseudomonas, Nitrobacter and Nitrosomonas help in the process to mineralize
the organic wastes (Panigrahi et al. 2005). Bacteria cells involved in the reduction of
metals are Geobacter metallireducens, which has been recently added in the list of
bacteria that eliminate radioactive waste of uranium, from water drainage during
mining as well as from polluted underground waters (Sasikumar and Papinazath
2003).
15.4.2 Fungi
Fungi have been exploited by human beings for many applications such as degradation, or deterioration, of a broad range of contaminants by the method called
mycodegradation or mycodeterioration (Leitão 2009). On the other hand, the main
process known as mycoremediation utilizes fungus for the removal of chemical
contaminants present in the soil. In this method, fungi uses certain biocatalysts and
acids which are secreted naturally for the decomposition of hazardous chemicals into
less or non-hazardous substances (Agwu and Kalu 2012; Prasad 2017, 2018; Prasad
et al. 2021). Fungus, alone or in contribution with bacterial cells or plants, is an
important component of biotechnology designed to biodegrade the polluted natural
resources (Harms et al. 2011).
15 The Role of Microorganisms in Remediation of Environmental Contaminants
433
heterotrophic genera of bacteria Micrococcus, Mycobacterium, Vibrio, Pseudomonas,
Corynebacterium,
Arthrobacter,
Achromobacter,
Acinetobacter,
Flavobacterium, Brevibacterium and Nocardia are found to be present (Jonsson
and Haller 2014). Among all of them, the best hydrocarbon-biodegrading bacteria
was Bacillus (Joutey et al. 2013). The bacterial strains which are capable to often
remediate aromatic hydrocarbons have been isolated so far, basically from the soil
with bacteria, i.e. Gram-negative, belongs to the genus Pseudomonas (Coelho et al.
2015). Microbes play a significant role in biodegradation of heavy metals which are
most volatile by the process of methylation. For instance, mercury (Hg II) easily
undergoes methylation into gaseous methyl mercury by various bacterial species, for
example, Staphylococcus, P. aeruginosa, Brevibacterium iodonium, Bacillus
pumilus, and Alcaligenes faecalis. Bacteria are capable to leach higher
concentrations of heavy metals such as arsenic, cobalt, copper, cadmium and zinc
from polluted soils, for example, acidophilic iron bacteria like Arthrobacter spp.,
Acidithiobacillus ferrooxidans, Pseudomonas veronii, Kocuria flava, Sporosarcina
ginsengisoli, Bacillus cereus, sulphur-oxidizing bacteria and Burkholderia spp. by
the process of methylation and redox reactions (Mateos et al. 2006; Joutey et al.
2013; Coelho et al. 2015). Detoxification-based, especially arsenic (V), reduction
has been best studied in E. coli (Mateos et al. 2006). Many catabolic plasmids had
been discovered in the species such as Alcaligenes, Arthrobacter, Flavobacterium,
Actinobacter, Moraxella, Klebsiella and Pseudomonas (Sayler and Ripp 2000). A
wide range of bacteria metabolize pesticides such as genera Alcaligenes,
Flavobacterium, Pseudomonas and Rhodococcus (Nawaz et al. 2011). Bacterial
species that belong to genera Bacillus, Cellulomonas, Acinetobacter, Pseudomonas,
Rhodoseudomonas, Nitrobacter and Nitrosomonas help in the process to mineralize
the organic wastes (Panigrahi et al. 2005). Bacteria cells involved in the reduction of
metals are Geobacter metallireducens, which has been recently added in the list of
bacteria that eliminate radioactive waste of uranium, from water drainage during
mining as well as from polluted underground waters (Sasikumar and Papinazath
2003).
15.4.2 Fungi
Fungi have been exploited by human beings for many applications such as degradation, or deterioration, of a broad range of contaminants by the method called
mycodegradation or mycodeterioration (Leitão 2009). On the other hand, the main
process known as mycoremediation utilizes fungus for the removal of chemical
contaminants present in the soil. In this method, fungi uses certain biocatalysts and
acids which are secreted naturally for the decomposition of hazardous chemicals into
less or non-hazardous substances (Agwu and Kalu 2012; Prasad 2017, 2018; Prasad
et al. 2021). Fungus, alone or in contribution with bacterial cells or plants, is an
important component of biotechnology designed to biodegrade the polluted natural
resources (Harms et al. 2011).
15 The Role of Microorganisms in Remediation of Environmental Contaminants
433