氟乐灵降解菌Bacillus sp.的分离鉴定及其降解特性

Separation, Identification and Degradation Characteristics of Trifluralin Degrading Strain Bacillus sp.

[目的]从长期被氟乐灵污染的土壤中筛选出能以氟乐灵为唯一碳氮源生长的细菌,并对其降解特性进行研究。[方法]以连作15年以上棉田土壤为材料,采用直接稀释涂布法分离得到1株能够降解氟乐灵的细菌D8,通过形态特征、生理生化特性和16S r DNA序列分析,对菌株D8进行鉴定;通过单因素试验研究降解特性。[结果]鉴定菌株D8为蜡样芽孢杆菌(Bacillus cereus),在氟乐灵质量浓度为50 mg/L、接种量为4%、外加氮源酵母浸粉0.1%、温度37℃、p H值为5.0的条件下,接种3 d后对氟乐灵降解率达到59.89%以上。[结论]该研究为氟乐灵的生物降解和土壤修复提供理论依据。

[Aims] The aims were to screen out the bacteria which capable of growing on trifluralin as a sole carbon and nitrogen source from the soil have been polluted with trifluralin, and the degradation characteristics were studied. [Methods] The strain D8, a bacterium which was able to degrade trifluralin, was separated from the soil which continuous cropping cotton for more than 15 years by direct dilution coating separation. Base on shape, physiological and biochemical characteristics, 16S rDNA sequence analysis, the degradation characteristics were studied by single factor experiment. [Results] The strain D8 was identified as Bacillus cereus. The optimal degrading conditions were： initial concentration of trifluralin of 50 mg/L, inoculation amount of 4%, additional nitrogen source of yeast extract powder 0.1%, pH 5.0 at 37 ℃. Under the optimal conditions, the degrading efficiency could reach more than 59.89% after 3 days. [Conclusions] The study provides theoretical basis for biodegradation of trifluralin and soil remediation.