Mechanism of atrazine metabolism by the microbial Y9 community and related soil–plant remediation effects

A bacterial community with atrazine-degrading capability, designated Y9, was enriched from cool-temperate farmland soil having a long-term atrazine (ATZ) application history. Under optimized culture conditions, Y9 degraded 98.62% of 50 mg/L ATZ within 8 h, with a half-life of only 2.02 h. A metabolomic analysis revealed that Y9 metabolizes ATZ to cyanuric acid via the synergistic cooperation of dechlorination-hydrolysis and oxidative dealkylation pathways. In soil remediation experiments, Y9 degraded 70% of 50 mg/kg ATZ within 1 day and achieved complete degradation within 14 days. Pot experiments demonstrated that soil remediated by Y9 alleviated the phytotoxic effects of ATZ on soybean, with plant growth indices and physiological functions recovering to normal levels. This study provides a bacterial community resource and theoretical basis for the bioremediation of ATZ-contaminated soil.