Preliminary study on thiamethoxam degrading bacteria isolated from corn plantation

Abstract

Aims: Thiamethoxam (THIA) is a pesticide that has been widely used for its effectiveness in controlling and preventing insect pests. However, the use of THIA diffused in soil, surface and groundwater pose severe toxicity to the ecosystem. The hazardous pollution caused by the toxicity of THIA demands for remediation to ensure degradation of THIA into its safe constituent elements. Thus, the aim of this study is to isolate and identify potential THIA degraders for future bioremediation. Methodology and results: Bacteria were isolated from soil sample collected at a corn plantation which utilizes THIA as a source of pesticide. Overall, two bacterial isolates were isolated from the soil sample. The bacterial isolates were screened and identified for their ability to degrade pesticide by culturing in minimal salt media (MSM) supplemented with 50 mg/L THIA. The growth of isolates was observed and analyzed through spectrophotometry analysis, standard plate count method and pH value of culture medium. As a result, isolate THIA 1 had been found to possess the ability to degrade pesticide as it showed a high rate in growth of bacteria compared to its controls. Meanwhile, isolate THIA 2 showed no degrading activities while under treatment as it showed similar rate of growth towards its control. Isolate THIA 1 was identified as Acinetobacter sp. UMTFA THIA 1. Conclusion, significance and impact of study:The isolation and identification of the pesticide degrading bacteria will provide promising source of pesticide degrading enzyme that can be further developed for enzymatic pesticide biodegradation. This will pave the way forward in bioremediation where new effective degradation tools can be developed for pesticide residue which otherwise lead to serious ecological problem.