Optimized atrazine biodegradation in Egyptian soils via native bacterial isolates and molecular insights using...

Area of Science:

• Environmental Microbiology
• Bioremediation Technologies
• Agricultural Science

Background:

• Atrazine is a widely used herbicide, posing environmental risks due to soil and water contamination.
• Effective bioremediation strategies are crucial for mitigating the ecological impact of atrazine pollution.

Purpose of the Study:

• To isolate and identify effective atrazine-degrading bacteria from Egyptian soil.
• To optimize biodegradation conditions using response surface methodology (RSM).
• To assess the potential of identified strains for agricultural bioremediation.

Main Methods:

• Isolation and screening of bacterial strains from atrazine-polluted soil.
• Identification using 16S rRNA sequencing and phylogenetic analysis.
• Biodegradation efficiency assessment using High-Performance Liquid Chromatography (HPLC).
• Optimization of biodegradation parameters using Response Surface Methodology (RSM) with Central Composite Design (CCD).

Main Results:

• Thirty-four out of forty-four bacterial isolates demonstrated atrazine degradation capabilities.
• Klebsiella sp. (HA19) and Ochrobactrum sp. (A7) showed high degradation efficiencies (81% and 81.3%).
• Optimized RSM conditions resulted in enhanced degradation rates of 94.2% and 96.7% for HA19 and A7, respectively.
• Degradation pathway involves deethylatrazine intermediate, with genes atzA, atzC, and atzD confirmed.

Conclusions:

• Klebsiella sp. and Ochrobactrum sp. are effective atrazine biodegraders with potential for bioremediation.
• RSM optimization significantly improves atrazine biodegradation efficiency.
• This study provides a viable, biosafety solution for atrazine-contaminated agricultural fields in Egypt.