Biodegradation of pyrazosulfuron-ethyl by Acinetobacter sp. CW17

Area of Science:

• Environmental microbiology
• Bioremediation of pesticides

Background:

• Pyrazosulfuron-ethyl is a widely used herbicide.
• Soil contamination by pyrazosulfuron-ethyl poses environmental risks.
• Microbial degradation offers a sustainable remediation approach.

Purpose of the Study:

• To isolate and identify microorganisms capable of degrading pyrazosulfuron-ethyl.
• To investigate the optimal conditions for pyrazosulfuron-ethyl biodegradation by the isolated strain.
• To elucidate the degradation pathway of pyrazosulfuron-ethyl.

Main Methods:

• Isolation of pyrazosulfuron-ethyl-degrading bacteria from contaminated soil.
• Identification of the bacterial strain using Biolog, phenotypic characteristics, and 16S rRNA gene sequencing.
• Optimization of biodegradation conditions (concentration, pH, temperature) and analysis of degradation products using LC/MS.

Main Results:

• Acinetobacter sp. strain CW17 was isolated and identified.
• Optimal degradation occurred at 30°C and neutral pH, with varying efficiency based on initial pyrazosulfuron-ethyl concentration (48.0% at 5.0 mg/L, 77.0% at 20.0 mg/L, 32.6% at 50.0 mg/L after 7 days).
• Two degradation metabolites were identified, suggesting cleavage of the sulfonylurea bridge.

Conclusions:

• Acinetobacter sp. CW17 is a promising candidate for pyrazosulfuron-ethyl bioremediation.
• Biodegradation efficiency is influenced by environmental factors like temperature and pH.
• The bacterium degrades pyrazosulfuron-ethyl via sulfonylurea bridge cleavage.