Persistence and biodegradation of quinalphos using soil microbes.

Area of Science:

• Environmental Microbiology
• Bioremediation
• Environmental Chemistry

Background:

• Organophosphate pesticides, like quinalphos, are persistent environmental pollutants.
• Quinalphos contamination poses risks to aquatic ecosystems and human health.
• Natural soil microbial communities offer potential solutions for pesticide degradation.

Purpose of the Study:

• To isolate and identify soil microorganisms capable of degrading quinalphos.
• To evaluate the efficiency of indigenous microbes for quinalphos biodegradation in aqueous media.
• To investigate both natural and induced biodegradation pathways of quinalphos.

Main Methods:

• Isolation of Bacillus and Pseudomonas spp. from quinalphos-contaminated soils.
• Batch experiments to assess quinalphos degradation in aqueous solutions.
• Analysis of quinalphos and metabolite concentrations using UV-Vis spectrophotometry and HPLC.
• Identification of degradation products using mass spectrometry.

Main Results:

• Isolated Bacillus and Pseudomonas spp. demonstrated quinalphos degradation capabilities.
• Natural degradation showed a metabolite (dihydroxy quinalphos oxon) after 160 days.
• Induced biodegradation by isolated microbes achieved >80% quinalphos degradation within 17 days.
• No quinalphos metabolites were detected during the induced biodegradation process.

Conclusions:

• Indigenous soil microbes, specifically Bacillus and Pseudomonas spp., are effective in degrading quinalphos.
• Induced biodegradation using these microbes offers a rapid and efficient method for quinalphos removal from water.
• Microbial bioremediation presents a promising strategy for managing organophosphate pesticide pollution.