Biodegradation of atrazine by Arthrobacter sp C3, isolated from the herbicide-contaminated corn field

The s-triazine herbicide, atrazine, has been well acknowledged as an important source causing contamination of soil, water, and sediment. Functional bacteria are one of the critical candidates for removing residual atrazine from contaminated environments. Here, seven bacterial strains showing atrazine-degrading ability were isolated from long-term atrazine-contaminated corn field and identified based on 16S rRNA gene sequencing. Among these bacterial isolates, a bacterium, later designated as Arthrobacter sp. C3, was found to be capable of completely degrading 25 mg/l atrazine. The high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis indicated that the atrazine was dechlorinated to hydroxyatrazine, a non-phytotoxic compound. The functional gene, trzN, which participates in the first step of atrazine degradation was successfully amplified and showed high similarity to the known trzN genes from different bacterial genera. Based on the HPLC-MS and the functional gene analysis, the functional bacterium C3 was speculated to degrade atrazine via dechlorination, which detoxified the herbicide. This study suggested a great potential of Arthrobacter sp. C3 to be used in indigenous bioremediation of atrazine in field.