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Studies on the degradation of the insecticide endosulfan by indigenous bacterial strains

Shodhganga@INFLIBNET

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Title Studies on the degradation of the insecticide endosulfan by indigenous bacterial strains
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Contributor Banwari Lal
 
Subject endosulfan
insecticide
bacterial strains
 
Description Endosulfan, a broad-spectrum insecticide consists of the and#61537;-and and#61538;-isomers. Widespread use of the insecticide endosulfan has led to the environmental accumulation of its residues (typical value ranging from 1-6 ppm) including those of its metabolite endosulfan sulfate, which are persistent and toxic to several environmental species. Thus there is an urgent need to find ways to degrade and detoxify this compound. Also as the understanding of the ways in which this compound might be degraded is limited, the present study was to understand the different routes through which endosulfan might be degraded and isolate a suitable strain with a high ability to degrade endosulfan. Initially agricultural soils (A1, A2 and A3) were collected and used for enrichment and isolation of endosulfan degrading strains using 3 different media Rich Medium (RM, endosulfan as a cosubstrate), Sulfur Free Medium (SFM, endosulfan as a sulfur source) and Minimal Salt Medium (MSM, endosulfan as a carbon source). However, out of the 18 enrichment cultures initiated only 2 initiated with A1 and A2 soils in RM (designated as Consortium 1 and Consortium 2) displayed endosulfan degradation with the formation of the intermediate endosulfan diol. The eight strains (RM1-RM8) isolated from these consortia displayed 11.5% - 46.7% degradation of endosulfan. However abiotic losses and formation of endosulfan diol was also observed control flasks that consisted of sterile medium. Another experiment was undertaken to observe the role of pH on the transformation of endosulfan. The results revealed that while abiotic losses occurred due to volatilization etc the specific chemical hydrolysis of endosulfan to endosulfan diol occurred at pH 7 and above. In order to minimize the chemical hydrolysis to endosulfan diol, the present RM was modified (M-RM) to include buffering capacity and reducing initial pH. In this case it was observed that while the chemical transformation of endosulfan to endosulfan diol was eliminated in sterile controls.
References p.184-211
 
Date 2013-01-09T10:16:14Z
2013-01-09T10:16:14Z
2013-01-09
n.d.
July 2009
n.d.
 
Type Ph.D.
 
Identifier http://hdl.handle.net/10603/6281
 
Language English
 
Relation -
 
Rights university
 
Format 211p.
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None
 
Coverage Biotechnology
 
Publisher New Delhi
Teri University
Centre for Bioresources and Biotechnology
 
Source INFLIBNET