Biodegradation of endosulfan by soil bacterial cultures

• A soil bacterium was able to use technical grade endosulfan as the carbon source.
• The isolate degraded α and β isomers of endosulfan without forming toxic products.
• The isolate was identified as Agrobacterium tumefaciens.
• The strain can be used as an efficient biocatalyst for remediating endosulfan.

Three bacterial isolates enriched from historically contaminated soil samples were investigated for their ability to use 100 mg L−1 of technical grade endosulfan as sole source of carbon and energy under aerobic conditions in liquid phase. Among the three isolates, maximum biodegradation ability was obtained by PT-3 which degraded >99% of 100 mg L−1 of endosulfan after 90 h of incubation and also used it as the source of sulfur. The isolate, PT-3 was identified as Agrobacterium tumefaciens and was able to use both α and β isomers of endosulfan with equal efficiencies without the accumulation of known toxic intermediates or end products. Endosulfan is known to be highly toxic to nitrogen fixing bacteria such as Rhizobium sp thereby reducing the fertility of soil. A. tumefaciens is a well known inhabitant of agricultural fields and therefore may be a valuable bioaugmenting agent for remediation of endosulfan contaminated sites.

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