Bacteria degrade atrazine and nicosulfuron in soil

A bacterial strain isolated from corn soil demonstrated the ability to simultaneously degrade atrazine e nicosulfuron and also promote improvements in soil attributes. Study identified the bacteria Priestess aryabhattai YB01 as an agent with potential for bioremediation in agricultural systems. The results indicate degradation of up to 56,99% for atrazine and 44,51% for nicosulfuron under optimized conditions.

The study demonstrates a direct impact on reducing residues of herbicides widely used in corn cultivation. Both compounds exhibit high persistence in the environment. Atrazine can remain in the soil for hundreds of days. Nicosulfuron also has a prolonged residual effect, especially in saline soils. These residues affect subsequent crops and reduce productivity.

YB01 strain

The YB01 strain was isolated from an area with a history of continuous herbicide application. Laboratory tests indicated greater degradation activity in the first 24 hours. Optimal conditions involved a temperature close to 30-35 °C, neutral pH, and inoculation of around 1%. Models based on artificial neural networks allowed the definition of ideal parameters to maximize degradation.

Genomic analysis revealed genes associated with the degradation of organic compounds. Metabolic mechanisms linked to hydrolysis and redox reactions were identified.

In the case of atrazine, degradation occurs through pathways that lead to the formation of cyanuric acid. This compound exhibits lower environmental toxicity compared to the original herbicide.

For nicosulfuron, degradation involves the breaking of specific chemical bonds, forming compounds such as ADMP and ASDM. These metabolites exhibit lower toxicity. Research indicates lower relative efficiency in the degradation of this herbicide, possibly due to the lower expression of specific genes in the soil.

Tests and efficiency

Soil tests confirmed the strain's efficiency. Atrazine degradation reached 76,77% after five days at higher inoculation density. For nicosulfuron, the rate reached approximately 53%. The results indicate the influence of native microbiota and soil composition on the process's efficiency.

In addition to degradation, the application of the bacteria promoted improvements in the chemical attributes of the soil. There was an increase of 4,03% in available nitrogen, 13,08% in phosphorus, and 7,17% in potassium. The organic matter content increased by 15,11%. The strain also reduced the soil pH, an effect associated with the production of organic acids.

Soil enzymatic activity increased after inoculation. Increases in urease, phosphatase, catalase, and sucrase were recorded. These indicators point to greater microbial activity and potential improvement in nutrient cycling.

The structure of the microbial community also changed. There was an increase in bacterial and fungal diversity. Groups associated with the decomposition of organic matter and nutrient cycling became predominant. This effect indicates synergy between the introduced strain and the native microbiota.

Further information at doi.org/10.1016/j.pestbp.2026.107099