Biodegradation of triadimefon by Stenotrophomonas sp. Y56 and its bioaugmentation in agricultural soil

Triadimefon (TF) is a pervasive triazole fungicide characterized by its high structural stability and environmental persistence, posing enduring ecological risks to soil systems. Microorganisms were the main drivers for TF removal in the environment; however, TF-degrading strains and their bioaugmentation applications remain insufficiently understood. In this study, a novel TF-degrading bacterium, Stenotrophomonas sp. Y56 was isolated from the activated sludge. The degradation efficiency of strain Y56 for 20 mg/L TF reached 76% within 24 h under the optimal conditions of pH 7.0-8.0 and 37-42 ℃, and with the addition of 0.6% acetate and 0.6% peptone. Strain Y56 degraded TF by carbonyl reduction to form triadimenol. The degradation half-life (T_1/2) of TF at concentrations of 110 mg/kg in agricultural soil by strain Y56 ranged from 3.9 to 5.0 d, which was 3.4-5.5 times shorter than that in natural soil (where the T_1/2 was 17.2-21.4 d). Strain Y56 alleviated TF-induced disruption of soil community structure, successfully colonized the soil, and concurrently promoted interactions within the bacterial community. This study provided critical insights into the environmental biochemistry of TF and a promising bioaugmentation strategy for TF-contaminated sites.