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Isolation, Screening and Selection of Efficient Chlorpyriphos Degrading Microorganisms

KrishiKosh

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Title Isolation, Screening and Selection of Efficient Chlorpyriphos Degrading Microorganisms
 
Creator Anuja George
 
Contributor K.S.Jagadeesh
 
Subject Agricultural Microbiology
 
Description The focus of the present study was to develop bacteria capable of bioremediation of
chlorpyriphos contaminated soil. This was attempted by isolating 28 bacterial isolates from
chlorpyriphos enriched soil samples and screening for biodegradation of the pesticide. Of the
screened bacterial isolates, 13 grew on mineral salts medium containing 100 ppm
chlorpyriphos as the sole carbon source. There was only a slight increase in the release of
chloride when the medium was supplemented with additional carbon sources such as succinic
acid, glucose and maltose (@ 1 g/l). The most promising chlorpyriphos degrading bacteria
were Pseudomonas sp. JA 15 and Enterobacter sp. JA 8 which degraded the pesticide by 98
and 93 per cent respectively in 7 days. Calcium alginate-immobilized Pseudomonas JA15
strain resulted in complete degradation of chlorpyriphos by 100 hours. Thin layer
chromatographic analysis of all the isolates revealed appearance of an unknown metabolite
having Rf value in the range 0.15-0.19. The enzyme involved in chlorpyriphos degradation
by Pseudomonas JA15 isolate was found to be extracellular.
These efficient strains were selected for the bioremediation of chlorpyriphos
contaminated soil. The bioaugmentation of the strains alone and in combination to the
contaminated soil resulted in higher degradation rate than was observed in uninoculated soils.
The phytotoxic effects of the pesticide on germination and growth of cowpea were
counteracted by the strains. The population of chlorpyriphos degrading bacteria in the
polluted soil was found to increase throughout the period of investigation due to breakdown
of the pesticide. The seed inoculation technique proved to be a promising method of
delivering the strain for the bioremediation of chlorpyriphos contaminated soil, as cowpea
root exudates supported the growth and multiplication of JA 15 strain.
 
Date 2016-10-17T10:46:23Z
2016-10-17T10:46:23Z
2005
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/80658
 
Format application/pdf
 
Publisher UAS, Dharwad