潮间带沉积物厌氧烃降解细菌的多样性及Desulfovibrio subterraneus ND17的分离鉴定

潮间带作为海陆交界处，易受到来自海洋的石油污染，且各类石油烃进入沉积物后的降解过程尚不清楚。前人在各类生境中对好氧微生物烃降解方面已有较多研究，但对近海潮间带环境中的厌氧烃降解鲜有报道。本研究对青岛女岛湾潮间带沉积物深层样品以混合烃（中长链烷烃、多环芳烃）为碳源，硫酸盐作为电子受体进行厌氧富集培养。富集菌群的细菌多样性表明在混合烃作为碳源的作用下，优势菌群转变为脱硫叠球菌科（Desulfosarcinaceae）、脱硫杆菌科（Desulfobacteraceae）等具有石油烃降解潜力的硫酸盐还原菌。经分离纯化得到一株厌氧烃降解菌ND17，与地下脱硫弧菌属模式种Desulfovibrio subterraneus HN2T 16S rRNA基因序列的相似度为99.93%。进一步实验表明，菌株ND17在厌氧条件下对二十四烷和菲的降解率可分别达到53.9%和35.7%。这也是首次对脱硫弧菌属单菌在厌氧条件下进行石油烃降解的研究。脱硫弧菌作为一种广泛分布在厌氧环境的细菌，本研究为进一步认识其在海洋石油污染环境中的修复潜力提供了支撑。

Diversity of anaerobic hydrocarbon-degrading bacteria in intertidal sediments and isolation and identification of Desulfovibrio subterraneus ND17

As a junction between land and sea, the intertidal zone is vulnerable to oil pollution from the ocean, and the degradation process of various types of petroleum hydrocarbons entering the sediment is still unclear. There have been many studies on aerobic microbial hydrocarbon degradation, but little has been reported on anaerobic hydrocarbon degradation in the offshore intertidal environment. In this study, anaerobic enrichment culture was conducted on deep intertidal sediment samples from Qingdao Nüdao Bay with mixed hydrocarbons (medium and long chain alkanes and polycyclic aromatic hydrocarbons) as carbon source and sulfate as electron acceptor. The bacterial diversity of the enriched flora indicated that the dominant flora changed to Desulfosarcinaceae, Desulfobacteraceae and other sulfate-reducing bacteria with petroleum hydrocarbon degradation potential under the effect of mixed hydrocarbons as carbon source. An anaerobic hydrocarbon-degrading strain ND17 was obtained by isolation and purification, with 99.93% similarity to the 16S rRNA gene sequence of Desulfovibrio subterraneus HN2T, the model species of Desulfovibrio subterraneus genus. Further experiments showed that strain ND17 could degrade eicosanoids and phenanthrene up to 53.9% and 35.7%, respectively, under anaerobic conditions. This is the first study on the degradation of petroleum hydrocarbons under anaerobic conditions by a single bacterium of the genus Desulfovibrio. As a widely distributed bacterium in anaerobic environments, this study supports further understanding of its remediation potential in marine petroleum-contaminated environments.