大西洋洋中脊深海多环芳烃降解菌群的优势菌分析

摘要：【目的】为了分析大西洋洋中脊深海海水及表层沉积物中多环芳烃(PAHs)降解菌群中的优势菌。【方法】采用富集培养法和平板涂布法从深海样品中分离可培养细菌及PAHs降解菌。通过16S rRNA基因测序完成系统发育分析。采用变性梯度凝胶电泳（DGGE）及DNA测序分析降解菌群中的优势菌。【结果】总共分离到16株细菌，包括一株PAHs降解菌Novosphingobium sp. 4D。系统发育分析发现，可培养细菌中两个最大的类群分别与Alcanivorax dieselolei NO1A（5/16）和Tistrella mobilis TISTR 1108T（5/16）亲缘关系最近。DGGE结果表明，在菌群MC2D中菌株4L（以及4M、4N， Alcanivorax dieselolei NO1A， 99.21％）、4D（Novosphingobium pentaromativorans US6-1T，97.07％）和4B（以及4E、4H、4K，Tistrella mobilis TISTR 1108T，＞99％）是降解菌群中的优势菌。而降解菌群MC3CO中的优势菌是菌株5C（以及5H，Alcanivorax dieselolei NO1A，＞99％）、条带5-8代表的未培养菌株（Novosphingobium aromaticivorans DSM 12444T，99.41%）、5J（Tistrella mobilis TISTR 1108T，99.52％）和5F（以及5G，Thalassospira lucentensis DSM 14000T，＜97％）。【结论】本研究发现在大西洋洋中脊深海海水及表层沉积物中Alcanivorax、Novosphingobium、Thalassospira、Tistrella属的细菌是PAHs降解菌群中的优势菌，其中的主要降解菌是Novosphingobium属的细菌。

Predominant strains of polycyclic aromatic hydrocarbon-degrading consortia from deep sea of the Middle Atlantic Ridge

Objective] In order to identify the predominant strains of polycyclic aromatic hydrocarbon (PAH)-degrading consortia harboring in sea water and surface sediment collected from deep sea of the Middle Atlantic Ridge. Methods] We employed enrichment method and spread-plate method to isolate cultivable bacteria and PAHs degraders from deep sea samples. Phylogenetic analysis was conducted by 16S rRJNA gene sequencing of the bacteria. Then we analyzed the dominant bacteria in the PAHs-degrading consortia by denaturing gradient gel electrophoresis (DGGE) combined with DNA sequencing. Results] Altogether 16 cultivable bacteria were obtained, including one PAHs degrader Novosphingobium sp. 4D. Phylogenetic analysis showed that strains closely related to Alcanivorax dieselolei N01A (5/16) and Tistrella mobilis TISTR 1108T(5/16) constituted two biggest groups among the cultivable bacteria. DGGE analysis showed that strain 4L (also 4M and 4N, Alcanivorax dieselolei NO1A,99.21%),4D ( Novosphingobium peruaromativorans US6-lT,97.07%) and 4B (also 4E,4H and 4K, Tistrella mobilis TISTR 1108T, >99%) dominated the consortium MC2D. While in consortium MC3CO,the predominant strains were strain 5C (also 5H, Alcanivorax dieselolei NO1A, > 99% ) , uncultivable strain represented by band 5-8 (Novosphingobium aromaticivorans DSM 12444T ,99.41% ) ,5J ( Tistrella mobilis TISTR 1108T ,99.52% ) and 5F (also 5G, Thalassospira lucentensis DSM 14000T , < 97 % ) . Conclusion] We found that strains of genus Alcanivorax, Novosphingobium, Tistrella and Thalassospira were predominant bacteria of PAHs-degrading consortia in sea water and surface sediment of Middle Atlantic Ridge deep sea, with Novosphingobium spp. as their main PAHs degraders.