一株多环芳烃降解菌的筛选及其降解特性

微生物修复是治理土壤多环芳烃(polycyclic aromatic hydrocarbons, PAHs)污染的主要方法，而高效降解菌筛选是微生物修复技术的重要基础。从北京焦化厂土壤中筛选分离得到一株PAHs降解菌Q3，通过生理生化和16S rDNA等分析手段鉴定其为Rhodococcus rhodochrous。结果表明：该菌株对芘的耐受能力较强，可降解初始浓度为200 mg·L⁻¹的芘；该菌株具有降解广谱性，可利用苯并[a]芘、苯并[b]荧蒽、二苯并[a,h]蒽、苯并[g,h,i]苝等9种PAHs为唯一碳源进行代谢，特别是对苯并[a]芘等高环PAHs具有较好的降解效果；此外，该菌株可有效降解模拟液中的混合PAHs，并且对野外被PAHs长期污染的土壤具有较好的强化修复效果。投加菌株处理后的处理组与对照组相比，土壤PAHs总去除率提高了24%。以上结果表明该菌株对环境中被PAHs污染的土壤具有较好的强化修复潜力，可为PAHs污染土壤的微生物修复技术提供技术参考。

Screening and degradation characteristics of a PAHs-degrading bacteria

Microbial remediation is the main way to remove polycyclic aromatic hydrocarbons (PAHs) from the contaminated soil. It is essential to screen highly efficient degrading bacteria for bioremediation of PAHs-contaminated environment. A PAHs-degrading strain Q3 was isolated from PAHs contaminated soil in Beijing Coking Plant and identified as Rhodococcus rhodochrous by biochemical analysis and 16S rDNA sequence. The results showed the strain Q3 could tolerate pyrene, and could degrade it with initial concentration up to 200 mg·L−1 in liquid medium. Meanwhile, Q3 showed broad-spectra property for PAHs degradation, and could use nine individual PAHs, including phenanthrene, pyrene, benzoanthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, dibenzo[a, h]anthracene or benzo[g, h, i]perylene, as sole carbon source to perform metabolism. Especially for PAHs with high-ring structures, such as benzo[a]pyrene, a relatively high degradation capacity also occurred. In addition, the strain Q3 could effectively degrade the mixed PAHs in the simulated solution, and had a good effect on enhancing remediation for long-term PAHs contaminated soil. The PAHs removal rate in treatment group increased by 24% compared with the control group. The results can provide a technical reference for the bioremediation technology of PAHs contaminated soil.