Kümmel Steffen, Herbst Florian-Alexander, Bahr Arne, Duarte Márcia, Pieper Dietmar H, Jehmlich Nico, Seifert Jana, von Bergen Martin, Bombach Petra, Richnow Hans H, Vogt Carsten
UFZ - Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstraße 15, D-04318 Leipzig, Germany University of Freiburg, Faculty of Biology, Schaenzlestraße 1, D-79104 Freiburg, Germany.
UFZ - Helmholtz Centre for Environmental Research, Department of Proteomics, Permoserstraße 15, D-04318 Leipzig, Germany.
FEMS Microbiol Ecol. 2015 Mar;91(3). doi: 10.1093/femsec/fiv006. Epub 2015 Jan 13.
Polycyclic aromatic hydrocarbons (PAH) are widespread and persistent environmental contaminants, especially in oxygen-free environments. The occurrence of anaerobic PAH-degrading bacteria and their underlying metabolic pathways are rarely known. In this study, PAH degraders were enriched in laboratory microcosms under sulfate-reducing conditions using groundwater and sediment samples from four PAH-contaminated aquifers. Five enrichment cultures were obtained showing sulfate-dependent naphthalene degradation. Mineralization of naphthalene was demonstrated by the formation of sulfide concomitant with the depletion of naphthalene and the development of (13)C-labeled CO2 from [(13)C6]-naphthalene. 16S rRNA gene and metaproteome analyses revealed that organisms related to Desulfobacterium str. N47 were the main naphthalene degraders in four enrichment cultures. Protein sequences highly similar to enzymes of the naphthalene degradation pathway of N47 were identified, suggesting that naphthalene was activated by a carboxylase, and that the central metabolite 2-naphthoyl-CoA was further reduced by two reductases. The data indicate an importance of members of the family Desulfobacteraceae for naphthalene degradation under sulfate-reducing conditions in freshwater environments.
多环芳烃（PAH）是广泛存在且持久的环境污染物，尤其是在无氧环境中。厌氧多环芳烃降解细菌的存在及其潜在代谢途径鲜为人知。在本研究中，利用来自四个多环芳烃污染含水层的地下水和沉积物样本，在硫酸盐还原条件下于实验室微观环境中富集多环芳烃降解菌。获得了五种富集培养物，显示出依赖硫酸盐的萘降解。通过硫化物的形成以及萘的消耗和[¹³C₆] - 萘中¹³C标记的CO₂的生成，证明了萘的矿化。16S rRNA基因和元蛋白质组分析表明，与脱硫杆菌属菌株N47相关的生物体是四种富集培养物中的主要萘降解菌。鉴定出与N47萘降解途径的酶高度相似的蛋白质序列，表明萘由羧化酶激活，并且中心代谢物2 - 萘甲酰辅酶A由两种还原酶进一步还原。数据表明脱硫杆菌科成员在淡水环境中硫酸盐还原条件下对萘降解具有重要作用。
