Microbial Degradation of the Organophosphorous Insecticide, Malathion Using the Natural Bacterial Isolate, Pseudomonas aeruginosa
Keywords:Malathion, Pseudomonas aeruginosa, Biodegradation, Pesticide, Bacteria.
Background: Pesticides are applied in agricultural fields to control pest population and to achieve crop
protection. But some of them persist in the environment and cause damage to the ecosystem. Hence, their
degradation becomes necessary. Microbes possess the capacity to degrade such xenobiotic compounds.
Objectives: The present study has been designed to isolate a bacterial strain effectively degrading Malathion
and to test its efficiency of degradation.
Materials and Methods: The bacterial strain was isolated from soil samples collected from agricultural
fields after serial dilution. Based on biochemical tests, it was identified. In 50, 100, 150 and 200 ppm
concentrations of Malathion in minimal broth, parameters like orthophosphate released, pH and turbidity
were measured for thirty hours. Influence of cell types and carbohydrate sources was also studied.
Results: The selected bacterial strain was identified as Pseudomonas aeruginosa. During treatment, both
orthophosphate levels and turbidity exhibited an increase while pH showed a decline. All the supplemented
carbohydrate sources enhanced degradation. Immobilized cells performed better than that of free cells in
long term treatment.
Conclusion: From the above findings it can be concluded that the isolated bacterial strain could be used in
the treatment of pesticide contaminants in agricultural fields.