Abstract：Abstract Atrazine (2-chloro-4-ethylamino-6-isopropyl-amino-1,3,5-triazine) is widely used in many countries, and has great threat to the environment and human beings. In order to obtain a highly efficient atrazine-degrading bacteria, the present study isolated a bacterial strain (LY-2) which could use atrazine as a sole nitrogen source to grow by enrichment culture. The source was from the surface soil of maize field where atrazine had been used for many years. LY-2 was identified as Enterobacter sp. strain. It was the first reported Enterobacter sp. strain in detail that could degrade atrazine. The results of PCR test showed that LY-2 contained atrazine-degrading gene atzA, atzB, and atzC, which were involved in the degradation of atrazine to cyanuric acid. The strain LY-2 could degrade 98.7% atrazine (100 mg/L) within 48 h. The optimum temperature range of the strain was 25~35 ℃ and the optimum pH range was 6~9. Additional nitrogen sources did not affect the degradation of atrazine. The experiment of soil remediation showed that the highest degradation rate of the strain was 86.7% after incubation for 7 d, and the highest degradation rate of strain was 90.1% after incubation for 14 d, the concentration of atrazine in contaminated soil was 100 mg/kg. The strain LY-2 shows good bioremediation effect in a relatively short period of time and has a better potential for bioremediation of atrazine-contaminated soil.
