Biodegradation of Dichlorovos (Organophosphate Pesticide) in Soil by Bacterial Isolates

Abstract

Excessive and continuous dispersion of pesticides which are toxic heterogeneous compound in the environment results in environmental pollution with ecological effects that require remediation. This study investigated the potential of microbial isolates to biodegrade or cleans up agricultural soil artificially contaminated with Dichlorvos (2, 2-dichlorovinyldimethylphosphate) pesticide.  A bacterial consortium which degraded Dichlorvos pesticide was isolated from agricultural soil using pour plate method.  This consortium was composed of four pure strains which were characterized based on their morphological and biochemical characteristics.  The strains were presumptively identifies as Proteus vulgaris, Vibrio sp., Serratia sp. and Acinetobacter sp. The consortium and the four bacteria were evaluated in order to discover their ability to biodegrade Dichlorvos pesticide in medium supplied with different nutrients (NH₄NO₃, KH₂PO₄ and NPK (20:10:10) fertilizer). The results showed that the bacterial consortium and the four bacteria isolates were able to grow in nutrient medium containing Dichlorvos as the only carbon source.  Moreover, the bacterial consortium was able to remove greater amount of DDP in soil amended with inorganic fertilizer (NPK) than those amended with NH₄NO₃ and KH₂PO₄, respectively.  These results indicate that the isolated strains can be used for waste biodegradation or bioremediation of organophosphate pesticide- contaminated soil or water.

Keywords: bacteria; biodegradation; dichlorvos; nutrient; organophosphate pesticides