Biodegradation of Endosulfan by a Soil Bacterium

A bacterium capable of metabolizing endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepine3-oxide) was isolated from cotton-growing soil and effectively shown to degrade endosulfan into endosulfan sulfate. The bacterium degraded 50% of the compound within 3 days of incubation. Endosulfan sulfate was the only terminal product and no other metabolites were formed during the incubation. Endosulfan and its metabolites were analyzed by gas chromatography. The metabolites formed indicated that the organism follows an oxidative pathway for metabolism of this pesticide. Therefore, the present study, microbial degradation of endosulfan by a soil bacterium, may provide a basis for the development of bioremediation strategies to remediate the pollutants in the environment.

Key Words:

• Endosulfan
• Microbial degradation
• Cotton
• Soils

ACKNOWLEDGEMENTS

One of the authors (HMS) wishes to thank Australian Center for International Agricultural Research, Australia for awarding him the John All Wright Fellowship during this period. We thank Dr. John H Skerritt, Deputy Director (Research) ACIAR Australia and Dr N.G.K. Karanth, former Deputy Director and Head, Food Protectants and Infestation Control Department, Central Food Technological Research Institute, Mysore, India, for sharing their knowledge and their guidance.