Abstract
The biotransformation of atrazine added to a mixture
of cotton and wheat straw (CWS) and inoculated with
the white-rot fungus, Pleurotus pulmonarius, was
studied, as a proposed system for bioremediation. The
concentration of methanol-extractable atrazine was
reduced, due to both biological transformation and
physical-chemical adsorption to the straw. Only 32%
of the total radioactivity added as 14C-ring-labeled
atrazine to pasteurized CWS inoculated with Pleurotus
was extracted two weeks after fungal colonization, and
less than 70% from non-inoculated CWS. The reduction
in extractable radioactivity increased with time of
incubation. No mineralization of the triazine ring was
found during six weeks of incubation, but transformation
to two groups of atrazine metabolites, chlorinated
and dechlorinated, occurred, as a result of the activity
of the fungus inoculated and natural bacterial population.
Unextractable radioactivity was recovered after
digesting the colonized substrate with H2S04, indicating
adsorption of the herbicide and its metabolites to
the straw. The results suggest that this process can be
used to detoxify atrazine by both adsorption and biodegradation.
Copyright © 1996 Elsevier Science Ltd.
AbstractThe biotransformation of atrazine added to a mixtureof cotton and wheat straw (CWS) and inoculated withthe white-rot fungus, Pleurotus pulmonarius, wasstudied, as a proposed system for bioremediation. Theconcentration of methanol-extractable atrazine wasreduced, due to both biological transformation andphysical-chemical adsorption to the straw. Only 32%of the total radioactivity added as 14C-ring-labeledatrazine to pasteurized CWS inoculated with Pleurotuswas extracted two weeks after fungal colonization, andless than 70% from non-inoculated CWS. The reductionin extractable radioactivity increased with time ofincubation. No mineralization of the triazine ring wasfound during six weeks of incubation, but transformationto two groups of atrazine metabolites, chlorinatedand dechlorinated, occurred, as a result of the activityof the fungus inoculated and natural bacterial population.Unextractable radioactivity was recovered afterdigesting the colonized substrate with H2S04, indicatingadsorption of the herbicide and its metabolites tothe straw. The results suggest that this process can beused to detoxify atrazine by both adsorption and biodegradation.Copyright © 1996 Elsevier Science Ltd.
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