Biodegradation of triazine herbicide metribuzin by the strain Bacillus sp. N1 |
| |
Authors: | Hao Zhang Yubin Zhang Zhiguang Hou Xian Wu Henan Gao Fengjie Sun |
| |
Institution: | 1. College of Resource and Environment , Jilin Agricultural University , Changchun , People's Republic of China;2. College of Plant Sciences , Jilin University , Changchun , People's Republic of China;3. School of Science and Technology , Georgia Gwinnett College , Lawrenceville , Georgia , USA |
| |
Abstract: | By enrichment culturing of soil contaminated with metribuzin, a highly efficient metribuzin degrading bacterium, Bacillus sp. N1, was isolated. This strain grows using metribuzin at 5.0% (v/v) as the sole nitrogen source in a liquid medium. Optimal metribuzin degradation occurred at a temperature of 30ºC and at pH 7.0. With an initial concentration of 20 mg L?1, the degradation rate was 73.5% in 120 h. If the initial concentrations were higher than 50 mg L?1, the biodegradation rates decreased as the metribuzin concentrations increased. When the concentration was 100 mg L?1, the degradation rate was only 45%. Degradation followed the pesticide degradation kinetic equation at initial concentrations between 5 mg L?1 and 50 mg L?1. When the metribuzin contaminated soil was mixed with strain N1 (with the concentration of metribuzin being 20 mg L?1 and the inoculation rate of 1011 g?1 dry soil), the degradation rate of the metribuzin was 66.4% in 30 days, while the degradation rate of metribuzin was only 19.4% in the control soil without the strain N1. These results indicate that the strain N1 can significantly increase the degradation rate of metribuzin in contaminated soil. |
| |
Keywords: | Metribuzin triazine herbicide biodegradation Bacillus sp N1 GC phylogenetic analysis |
|
|