“Studies on Bioremediation of Isoprothiolane, fungicide/insecticide and Glyphosate, a herbicide and Monitoring of Biodegradation using Biosensors
IR@CFTRI: CSIR-Central Food Technological Research Institute, Mysore
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Relation |
http://ir.cftri.com/10738/
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Title |
“Studies on Bioremediation of Isoprothiolane, fungicide/insecticide and
Glyphosate, a herbicide and Monitoring of Biodegradation using
Biosensors
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Creator |
Arul Selvi, A.
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Subject |
26 Pesticide Chemistry
01 Biotechnology and Bioengineering |
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Description |
Glyphosate [N-(phosphonomethyl) glycine] is a broad-spectrum, non
selective, systemic, post-emergence herbicide used both agriculturally and
domestically. It is the active ingredient in a number of commercial herbicides
produced by Monsanto, Cheminova, and Zeneca Corp. Glyphosate is a member
of the amino acid herbicide family, and its mode of action is through inhibition of
5-enolpyruvylshikimate- 3-phosphate synthase (EPSP), an enzyme of the
shikimic acid pathway. This enzyme is important in the biosynthesis of the
aromatic amino acids phenylalanine, tyrosine, and tryptophan. A blockage of the
shikimic acid pathway leads to a depletion of the free pool of aromatic amino
acids in higher plants consumption of it results in symptoms such as intestinal
pain, vomiting, excess fluid in the lungs, pneumonia, clouding of consciousness,
and destruction of red blood cells. Short term exposure to glyphosate can cause
breathing difficulties, loss of muscle control and convulsions.
Isoprothiolane (di-isopropyl 1, 3-dithiolan-2-ylidenemalonate), a systemic
fungicide, is effective against Pyricularia oryzae, which causes blast disease in
rice. It is applied at 3.2–4.8 kg/ ha. Because of a high rate of application, there is
an appreciable risk of ground water and surface water contamination by
isoprothiolane, particularly in the agro-climatic zone having light soil and high
rainfall. With continuous usage, these pesticides enter the human body via food
chain. Residues of these pesticides have been detected in soil, water and air.
A microbial consortium capable of degrading glyphosate and
isoprothiolane was isolated in the laboratory by long term enrichment. The
consortium was made of 10 bacterial isolates of which 7 belonged to
Pseudomonas sp. and one each of Flavobacterium , Vibrio and Burkholderia sp.
Conditions were optimized by response surface methodology. The maximum
predicted percentage degradation of 100, 100, 100, 82 and 73 was obtained
respectively for, 20, 40, 50, 75 and 100 ppm initial glyphosate concentrations at
pH 6.60 with an incubation temperature of 30 0C and inoculum concentration of
1146 g protein/ml. Similarly the maximum predicted percentage degradation of
100, 100, 100, 100 and 95.5 was obtained respectively for 5, 10, 20, 30 and 50
ppm initial isoprothiolane concentrations at pH levels 7.7, 6.8, 6.2, 4.7 and 4.6
with an incubation temperature of 30 0C and inoculum concentration of 50 g
protein/ml. The degradation of these pesticides by the microbial consortium
increased with time. The degradation reached 100% by 120 h of incubation for
these pesticides.
Residues of glyphosate and isoprothiolane are generally analyzed by thin
layer chromatography, gas chromatography and High performance liquid
chromatography which are expensive, labour intensive, require extensive clean
up and are not suited for on field assay. Immunoassay is highly sensitive,
specific, on- field method, does not need sample clean up and has high
throughput of samples. In our lab we attempted to develop an immunoassay for
the detection of glyphosate and isoprothiolane by using avian antibodies.
Glyphosate and isoprothiolane levels up to 2 ng could be detected by Well- Dot.
Signal amplification improved the detection signal with the same sensitivity.
Immunosensor based on DNA coated CdS nanoparticles and antibody coated
CdS nanoparticles were developed for the detection of glyphosate and
isoprothiolane. The detection limit by these nanoparticles based methods was
0.2 ng /ml.
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Contributor |
Manonmani, H. K.
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Date |
2011
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Type |
Thesis
NonPeerReviewed |
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Format |
pdf
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Language |
en
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Identifier |
http://ir.cftri.com/10738/1/arul_selvi_a.pdf
Arul Selvi, A. (2011) “Studies on Bioremediation of Isoprothiolane, fungicide/insecticide and Glyphosate, a herbicide and Monitoring of Biodegradation using Biosensors. Doctoral thesis, University of Mysore. |
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