Atrazine mineralization by Stenotrophomonas maltophilia and Agrobacterium tumefaciens Egyptian soil isolates

Atrazine is a water pollutant that has serious effects to human being and living organisms, thus it should be eliminated for environmental safety. Among the various methods used for its removal, biodegradation gains attraction due to its cost-effectiveness and environmental friendly nature. For this purpose, soil samples having previous history of treatment with atrazine were collected from El-Beheira Governorate, Egypt. The efficiency of the isolates to remove and mineralize atrazine was tested. Two bacterial strains achieved high removal percentage (up to 80% for S3) of atrazine during the first 7 h. These two bacterial strains were identified as Stenotrophomonas maltophilia and Agrobacterium tumefaciens using molecular identification based on sequencing of 16S rRNA gene. All the 16S nucleotides sequences of bacteria were applied and conserved in GeneBank. Agrobacterium tumefaciens mineralizes higher percentage of atrazine at shorter time relative to Stenotrophomonas maltophilia. External carbon source plays a key role in atrazine mineralization.