Chlamydomonas mexicana to atrazine by accumulating atrazine in cells and subsequently degrading it, reaching a degradation rate of 14–36%. There are many other
microorganisms such as Streptomyces spp., Arthrobacter fluorescens, and
A. giacomelloi, Chlorella vulgaris, Chlamydomonas reinhardtii, Clostridium
sphenoides, and S. japonicum UT26, which possessed the potential of degrading
organochlorine insecticides (Boudh et al. 2017; Boudh and Singh 2019).
Endosulfan is another toxic, persistent, and widely used broad-spectrum
cyclodine organochlorine pesticide. Achromobacter xylosoxidans strain C8B was
isolated from the soil, using endosulfan as the only sulfur source, through the
selective enrichment technique (Singh and Singh 2011). This bacterial strain
degraded 94.12% α-endosulfan, 84.52% β-endosulfan, and 80.10% endosulfan
sulfates, respectively, possibly by the formation of dichloro-diphenyltrichloroethane (DDT), an organochlorine compound still used in agriculture and
mosquito control in many developing countries. A p,p
0 -DDT degrading bacterial
strain Staphylococcus haemolyticus was isolated from soil containing DDT residues
in the range of 0.17–9.84 ng g
À1 soil and reduced by 37.4% of p,p
0 -DDT in 10 days
(Sonkong et al. 2008). A Micrococcus strain degraded pyrethroid pesticide
cypermethrin, which yields 3-phenoxybenzoate yield by hydrolysis of ester linkage,
resulting in loss of its insecticidal activity (Tallur et al. 2008). The degradation
product 3-phenoxybenzoate was further metabolized by diphenyl ether cleavage to
give protocatechuate and phenol. Both of which on oxidation by the ortho-cleavage
pathway led to the complete mineralization of cypermethrin. Similarly, Naphade
et al. (2012) isolated five different strains of soil bacteria, namely Pseudomonas
psychrophila, P. aeruginosa, Devosia yakushimensis, Paracoccus chinensis, and
Planococcus rifietoensis. Simazine, the active ingredient of 2-chloro-S-triazene
herbicides, was biodegraded to almost 100% efficiency in 4 days by the
Arthrobacter ureafaciens strain NC isolated from the rhizosphere soil (Błaszak
et al. 2011).
Bromoxinil octanoate (BOO) is a toxic and common herbicide used for control of
annual broad-leaved weeds applied in the maize crop (Cai et al. 2011). Cai et al.
(2011) reported the degradation of these herbicides by the bacterial strain
Acinetobacter spp. XB2 isolated from contaminated soil. The strain XB2 reduced
100 mg L
À1 BOO to undetectable levels within 72 h under optimal conditions.
Similarly, broad-spectrum herbicide glyphosate is widely used to control perennial
and annual post-emergent weeds (Duke 2018). Fan et al. (2012) isolated Bacillus
cereus strain from herbicide-contaminated soil, which exhibited potent glyphosate
degradation potential. This strain utilized 94.47% of glyphosate and reduced it to
AMPA, glycosylate, sarcosine, glycine, and formaldehyde through C-P lyase and
glyphosate oxidoreductase activity.
Liu et al. (2010) isolated an Arthrobacter strain T3AB1, which used atrazine as
the only carbon and nitrogen source, from maize field treated with atrazine in
Heilongjiang province. The bacterium degraded more than 99% at 500 mg L
À1
atrazine (pH 8.0) within 72 h under optimal conditions. Furthermore, this strain was
found to use other herbicides such as imazamox, imazethapyr, trifluralin, clomazone,
and fomesafen as a single carbon and nitrogen source at a degradation rate of
2 Bioremediation of Pesticides: An Eco-Friendly Approach for Environment. . .
37
microorganisms such as Streptomyces spp., Arthrobacter fluorescens, and
A. giacomelloi, Chlorella vulgaris, Chlamydomonas reinhardtii, Clostridium
sphenoides, and S. japonicum UT26, which possessed the potential of degrading
organochlorine insecticides (Boudh et al. 2017; Boudh and Singh 2019).
Endosulfan is another toxic, persistent, and widely used broad-spectrum
cyclodine organochlorine pesticide. Achromobacter xylosoxidans strain C8B was
isolated from the soil, using endosulfan as the only sulfur source, through the
selective enrichment technique (Singh and Singh 2011). This bacterial strain
degraded 94.12% α-endosulfan, 84.52% β-endosulfan, and 80.10% endosulfan
sulfates, respectively, possibly by the formation of dichloro-diphenyltrichloroethane (DDT), an organochlorine compound still used in agriculture and
mosquito control in many developing countries. A p,p
0 -DDT degrading bacterial
strain Staphylococcus haemolyticus was isolated from soil containing DDT residues
in the range of 0.17–9.84 ng g
À1 soil and reduced by 37.4% of p,p
0 -DDT in 10 days
(Sonkong et al. 2008). A Micrococcus strain degraded pyrethroid pesticide
cypermethrin, which yields 3-phenoxybenzoate yield by hydrolysis of ester linkage,
resulting in loss of its insecticidal activity (Tallur et al. 2008). The degradation
product 3-phenoxybenzoate was further metabolized by diphenyl ether cleavage to
give protocatechuate and phenol. Both of which on oxidation by the ortho-cleavage
pathway led to the complete mineralization of cypermethrin. Similarly, Naphade
et al. (2012) isolated five different strains of soil bacteria, namely Pseudomonas
psychrophila, P. aeruginosa, Devosia yakushimensis, Paracoccus chinensis, and
Planococcus rifietoensis. Simazine, the active ingredient of 2-chloro-S-triazene
herbicides, was biodegraded to almost 100% efficiency in 4 days by the
Arthrobacter ureafaciens strain NC isolated from the rhizosphere soil (Błaszak
et al. 2011).
Bromoxinil octanoate (BOO) is a toxic and common herbicide used for control of
annual broad-leaved weeds applied in the maize crop (Cai et al. 2011). Cai et al.
(2011) reported the degradation of these herbicides by the bacterial strain
Acinetobacter spp. XB2 isolated from contaminated soil. The strain XB2 reduced
100 mg L
À1 BOO to undetectable levels within 72 h under optimal conditions.
Similarly, broad-spectrum herbicide glyphosate is widely used to control perennial
and annual post-emergent weeds (Duke 2018). Fan et al. (2012) isolated Bacillus
cereus strain from herbicide-contaminated soil, which exhibited potent glyphosate
degradation potential. This strain utilized 94.47% of glyphosate and reduced it to
AMPA, glycosylate, sarcosine, glycine, and formaldehyde through C-P lyase and
glyphosate oxidoreductase activity.
Liu et al. (2010) isolated an Arthrobacter strain T3AB1, which used atrazine as
the only carbon and nitrogen source, from maize field treated with atrazine in
Heilongjiang province. The bacterium degraded more than 99% at 500 mg L
À1
atrazine (pH 8.0) within 72 h under optimal conditions. Furthermore, this strain was
found to use other herbicides such as imazamox, imazethapyr, trifluralin, clomazone,
and fomesafen as a single carbon and nitrogen source at a degradation rate of
2 Bioremediation of Pesticides: An Eco-Friendly Approach for Environment. . .
37