Plant Science Research, Vol. 34, 2012

Isolation and characterization of a chlorpyrifos degrading bacterium from rice soil

The organophosphorus insecticide, chlorpyrifos has been widely used in agriculture, in veterinary against house hold pests, and in field agriculture for subterranean termite control. Due to its slow rate of degradation in soil it can persist for extended periods in soil with significant concern to the environment. A soil bacterium capable of utilizing chlorpyrifos as the sole source of carbon and energy was isolated from rice soil enriched with repeated application of chlorpyrifos (10 mg/kg). The strain named CRRI NF3, was preliminarily identified as Bacillus sp. based on its morphological, physiological and biochemical tests as well as 16s rRNA gene sequence analysis. Bioremediation of chlorpyrifos was examined using CRRI NF3 inoculated to the soil treated with 10 mg/kg chlorpyrifos and resulted in faster degradation than control soils without any inoculation. The optimum pH, temperature could have promoted degradation.