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从潜在多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)污染的油田区域采集土壤样品,以菲为唯一碳源且添加硝酸根的培养基来富集土壤中的菲反硝化降解菌群.随后,通过定量PCR(Polymerase Chain Reaction)测定了获取的富集菌群中反硝化相关功能基因(硝酸还原酶基因nar G、亚硝酸还原酶基因nir S)的丰度,并通过Illumina Mi Seq测序对其中的细菌群落结构进行解析.结果表明,获取到的3个菌群(PDN-1、PDN-2和PDN-3)12 d内对菲的降解率分别为45.18%、34.04%和25.92%.各富集培养菌群中nar G的丰度均高于nir S,且菲降解率最高的PDN-1中的反硝化相关基因丰度较低.Illumina Mi Seq测序结果表明,菲降解率最高的富集菌群PDN-1同时也具有较高的细菌多样性指数,变形菌门(Proteobacteria)、疣微菌门(Verrucomicrobia)和拟杆菌门(Bacteroidetes)是各富集菌群中的优势菌门,且Proteobacteria在3个富集菌群PDN-1(97.78%)、PDN-2(96.57%)、PDN-3(93.90%)中的比例均最高.变形菌门的Pseudomonas(γ-Proteobacteria)和Methylophilus(β-Proteobacteria)则是各富集菌群中最大的优势菌属,前者为公认的PAHs降解菌,而后者则为能够利用还原型“一碳化合物”的特殊菌属.细菌多样性与菲的降解率呈正相关,表明菲的反硝化降解可能是多种细菌参与的共同结果.上述结果可为揭示典型PAHs反硝化降解的微生物机制提供理论依据,同时为深入研究反硝化与菲代谢的偶联机理打下基础.
Soil samples were collected from oilfields contaminated with Polycyclic Aromatic Hydrocarbons (PAHs), and phenanthrene was added as a carbon source and nitrate was added to enrich the soil for phenanthrene-denitrification degradation. Subsequently, PCR (Polymerase Chain Reaction) was used to determine the abundance of denitrification-related functional genes (nitrate reductase gene narG, nitrite reductase gene nir S) in the enriched microflora. The abundance of the bacteria (PDN-1, PDN-2 and PDN-3) within 12 d were 45.18%, 34.04% and 25.92%, respectively. The abundance of nar G was higher than that of nir S in cultured bacteria and the abundance of denitrification-related genes in PDN-1 with the highest phenanthrene degradation rate was lower.Illumina Mi Seq sequencing results showed that the enrichment bacteria with the highest phenanthrene degradation rate Cluster PDN-1 also has a high bacterial diversity index. Proteobacteria, Verrucomicrobia and Bacteroidetes are the dominant fungi in each enriched microbial community, and Proteobacteria Among the three enrichment groups PDN-1 (97.78%), PDN-2 (96.57%) The highest proportion of PDN-3 (93.90%) were Pseudomonas (γ-Proteobacteria) and Methylophilus (β-Proteobacteria) While the latter was a special genus that could utilize reduced carbon monoxide.The bacterial diversity was positively correlated with the phenanthrene biodegradation rate, indicating that the denitrification of phenanthrene may be the common result of a variety of bacteria. The results can provide a theoretical basis for revealing the microbial mechanism of denitrification degradation of typical PAHs, and lay a foundation for further study on the coupling mechanism of denitrification and phenanthrene metabolism.