Persistence of fipronil, a new molecule in extensive use against various insect pests is causing serious
problems to the environment. Bacillus firmus was isolated by selective enrichment from soil samples collected
from sugar fields with known history of pesticide usage and evaluated for metabolization of fipronil
in clay loam soil. Soil samples in 50 g aliquotes were fortified with fipronil @ 0.50–1.50 mg kg1 and
inoculated with B. firmus cells (45 107 CFU mL1) and incubated at 25 C. Each sample in triplicates was
drawn periodically up to 56 d and residual fipronil contents analyzed by gas liquid chromatograph. Fipronil
residues were not detected after 35 d at lower doses of fipronil (@ 0.50, 0.75 and 1.00 mg kg1). However,
at higher doses (@ 1.25 and 1.50 mg kg1) than this total metabolization of fipronil could be
observed after 35 and 42 d, respectively. Thus whereas, B. firmus proved its potential in efficient metabolization
of fipronil, the period required for the same was dose dependent. Amongst various metabolites
of fipronil degradation, fipronil sulfide was found to be the main metabolite followed by fipronil sulfone
and fipronil amide. Though, desulfinyl metabolite earlier reported as one of the main metabolite of fipronil
degradation, the existence of the same was not detected in any of the treatment.
Persistence of fipronil, a new molecule in extensive use against various insect pests is causing seriousproblems to the environment. Bacillus firmus was isolated by selective enrichment from soil samples collectedfrom sugar fields with known history of pesticide usage and evaluated for metabolization of fipronilin clay loam soil. Soil samples in 50 g aliquotes were fortified with fipronil @ 0.50–1.50 mg kg1 andinoculated with B. firmus cells (45 107 CFU mL1) and incubated at 25 C. Each sample in triplicates wasdrawn periodically up to 56 d and residual fipronil contents analyzed by gas liquid chromatograph. Fipronilresidues were not detected after 35 d at lower doses of fipronil (@ 0.50, 0.75 and 1.00 mg kg1). However,at higher doses (@ 1.25 and 1.50 mg kg1) than this total metabolization of fipronil could beobserved after 35 and 42 d, respectively. Thus whereas, B. firmus proved its potential in efficient metabolizationof fipronil, the period required for the same was dose dependent. Amongst various metabolitesof fipronil degradation, fipronil sulfide was found to be the main metabolite followed by fipronil sulfoneand fipronil amide. Though, desulfinyl metabolite earlier reported as one of the main metabolite of fipronildegradation, the existence of the same was not detected in any of the treatment.
การแปล กรุณารอสักครู่..
