Journal Article

Anaerobic naphthalene degradation by sulfate-reducing Desulfobacteraceae from various anoxic aquifers

Bahr, Arne, Bombach, Petra, Richnow, Hans H., Seifert, Jana, Duarte, Márcia, Vogt, Carsten, Herbst, Florian-Alexander, von Bergen, Martin, Kümmel, Steffen, Jehmlich, Nico, Pieper, Dietmar H.

2015

Overview

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 13C-labeled CO2 from [13C6]-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. By combining laboratory microcosms, stable isotope tools, illumina amplicon sequencing and metaproteomics, it is demonstrated that phylotypes affiliated to the known sulfate-reducing hydrocarbon-degrading Desulfobacterium sp. 47 are widespread anaerobic naphthalene degraders.

• Publisher: Oxford University Press
• Subject: Anaerobiosis / Aquifers / Biodegradation / Carbon dioxide / Carboxy-Lyases - metabolism / Chemical properties / Contaminants / Deltaproteobacteria - enzymology / Deltaproteobacteria - genetics / Deltaproteobacteria - metabolism / Depletion / Ecology / Enrichment / Environmental aspects / Environmental Pollutants - metabolism / Environmental Restoration and Remediation - methods / Freshwater environments / Groundwater / Groundwater - microbiology / Metabolic pathways / Metabolites / Methods / Microbiology / Microcosms / Mineralization / Naphthalene / Naphthalenes - metabolism / Oxidation-Reduction / Oxidoreductases - metabolism / Physiological aspects / Polycyclic aromatic hydrocarbons / Reductases / RNA, Ribosomal, 16S - genetics / rRNA 16S / Sediment samplers / Sulfate reduction / Sulfate-reducing bacteria / Sulfates / Sulfates - metabolism / Sulfides