Identification and Characterization of Bacterial Strains Capable of Degrading Atrazine and Metribuzin Herbicides in Sugarcane Fields

The usage of degrading bacterial strains has emerged as an innovative method to reduce pollution resulting from herbicide application. In 2022–2023, bacterial strains capable of degrading atrazine and metribuzin were isolated and identified from contaminated soils of six sugarcane farms in Khuzestan province, Iran. The study found 13 strains capable of growing in a specific culture medium (SSM) containing 10% atrazine, and 10 strains in a metribuzin-containing medium. Phenotypic tests, along with amplification of the 16S rRNA gene region, identified Stenotrophomonas sp, Brucella sp, Ensifer adhaerens , Pseudomonas aeruginosa , and Pseudomonas putida for atrazine, and Stenotrophomonas sp, Brucella sp, and E. adhaerens for metribuzin. Furthermore, the results indicated that E. adhaerens and Brucella sp. were able to grow on a combination of these two herbicides. Stenotrophomonas sp 22A displayed the lowest minimum inhibitory concentration (MIC) value (120 μL/mL) for atrazine, while Brucella sp 64A exhibited the highest MIC value at (230 μL/mL). Furthermore, the lowest MIC value for metribuzin was observed in Stenotrophomonas sp 63 M (180 μL/mL), in contrast to E. adhaerens 90 M which recorded the highest MIC value (230 μL/mL). The growth curve of bacterial absorbance rate (OD600) was measured using a microplate reader, and P. aeruginosa 15A and Stenotrophomonas sp 63 M had the highest degradation rate for atrazine and metribuzin, respectively. In conclusion, the use of degrading bacterial strains has notable potential as a method for reducing pollution resulting from herbicide use.