a College of Resource and Environment , Jilin Agricultural University , Changchun , People's Republic of China.
J Environ Sci Health B. 2014;49(2):79-86. doi: 10.1080/03601234.2014.844610.
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 10(11) 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.
通过对受二甲戊灵污染的土壤进行富集培养，分离到一株高效降解二甲戊灵的细菌，命名为芽孢杆菌 N1。该菌株能以 5.0%（v/v）二甲戊灵作为唯一氮源在液体培养基中生长。最佳降解条件为温度 30℃、pH7.0。在初始浓度为 20mg/L 时，120h 内的降解率为 73.5%。当初始浓度高于 50mg/L 时，随着二甲戊灵浓度的增加，生物降解率降低。当浓度为 100mg/L 时，降解率仅为 45%。在初始浓度为 5mg/L 至 50mg/L 之间，降解符合农药降解动力学方程。当受二甲戊灵污染的土壤与浓度为 20mg/L 的 N1 菌株（接种率为 10(11)g(-1)干土）混合时，在 30 天内，二甲戊灵的降解率为 66.4%，而在没有 N1 菌株的对照土壤中，二甲戊灵的降解率仅为 19.4%。这些结果表明，N1 菌株可以显著提高污染土壤中二甲戊灵的降解率。
