The aromatic hydrocarbon naphthalene, which occurs in coal and oil, can be degraded by aerobic or anaerobic microorganisms. A wide‐spread electron acceptor for the latter is sulfate. Evidence for in situ naphthalene degradation stems in particular from the detection of 2‐naphthoate and [5,6,7,8]‐tetrahydro‐2‐naphthoate in oil field samples. Because such intermediates are usually not detected in laboratory cultures with high sulfate concentrations, one may suppose that conditions in reservoirs, such as sulfate limitation, trigger metabolite release. Indeed, if naphthalene‐grown cells of marine sulfate‐reducing Deltaproteobacteria (strains NaphS2, NaphS3 and NaphS6) were transferred to sulfate‐free medium, they released 2‐naphthoate and [5,6,7,8]‐tetrahydro‐2‐naphthoate while still consuming naphthalene. With 2‐naphthoate as initial substrate, cells produced [5,6,7,8]‐tetrahydro‐2‐naphthoate and the hydrocarbon, naphthalene, indicating reversibility of the initial naphthalene‐metabolizing reaction. The reactions in the absence of sulfate were not coupled to observable growth. Excretion of naphthalene‐derived metabolites was also achieved in sulfate‐rich medium upon addition of the protonophore carbonyl cyanide4‐(trifluoromethoxy)phenylhydrazone or the ATPase inhibitor N,N′‐dicyclohexylcarbodiimide. In conclusion, obstruction of electron flow and energy gain by sulfate limitation offers an explanation for the occurrence of naphthalene‐derived metabolites in oil reservoirs, and provides a simple experimental tool for gaining insights into the anaerobic naphthalene oxidation pathway from an energetic perspective.

中文翻译：

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能量缺乏对厌氧海洋萘降解硫酸盐还原菌释放代谢物的影响。

发生在煤和石油中的芳香烃萘可以被好氧或厌氧微生物降解。后者的广泛电子受体是硫酸盐。原位萘降解的证据尤其来自于油田样品中2-萘甲酸和[5,6,7,8]-四氢-2-萘甲酸的检测。由于通常在高硫酸盐浓度的实验室培养物中未检测到此类中间产物，因此人们可能会认为储层中的条件（例如硫酸盐限制）会触发代谢物的释放。的确，如果将海洋生长减少硫酸盐的三角洲细菌的萘生长细胞（菌株NaphS2，NaphS3和NaphS6）转移到无硫酸盐的培养基中，它们会释放2-萘甲酸和[5,6,7,8]-四氢-2-萘甲酸。同时仍在消耗萘。以2-萘甲酸酯为初始底物，细胞产生[5,6,7,8]-四氢-2-萘甲酸和烃萘，表明初始萘代谢反应具有可逆性。不存在硫酸盐的反应未与可观察到的生长耦合。通过添加质子载体羰基氰化物4-（三氟甲氧基）苯ase或ATPase抑制剂，也可以在富含硫酸盐的培养基中排泄萘衍生的代谢物。N，N'-二环己基碳二亚胺。总之，硫酸盐限制阻碍电子流动和能量获取，这为油藏中萘衍生的代谢物的发生提供了解释，并为从能量的角度深入了解厌氧萘氧化途径提供了简单的实验工具。