Biodegradation of pendimethalin by Bacillus subtilis Y3

Area of Science:

• Environmental microbiology
• Bioremediation of pesticides

Background:

• Pendimethalin is a widely used herbicide.
• Microbial degradation offers a sustainable approach to herbicide removal.

Purpose of the Study:

• Isolate and identify efficient pendimethalin-degrading bacteria.
• Elucidate the metabolic pathway and key enzymes involved in pendimethalin degradation.

Main Methods:

• Isolation and identification of bacterium strain Y3 (Bacillus subtilis).
• High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS) for metabolite identification.
• Enzyme assays to detect nitroreductase activity and determine optimal conditions.

Main Results:

• Strain Y3 degraded 99.5% of 100mg/L pendimethalin in 2.5 days.
• Identified three metabolic products and proposed a new degradation pathway.
• Detected a nitroreductase enzyme, with optimal activity at 30°C and pH 7.5, influenced by various metal ions.

Conclusions:

• Bacillus subtilis strain Y3 is a highly efficient pendimethalin degrader.
• A novel microbial degradation pathway for pendimethalin has been elucidated.
• The identified nitroreductase is a key enzyme in this degradation process.