Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA.
Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, USA.
Microb Ecol. 2018 Aug;76(2):362-371. doi: 10.1007/s00248-017-1136-2. Epub 2018 Jan 11.
Over-the-counter pharmaceutical compounds can serve as microbial substrates in wastewater treatment processes as well as in the environment. The metabolic pathways and intermediates produced during their degradation, however, are poorly understood. In this study, we investigate an anaerobic wastewater community that metabolizes naproxen via demethylation. Enriched cultures, established from anaerobic digester inocula receiving naproxen as the sole carbon source, transformed naproxen to 6-O-desmethylnaproxen (DMN) within 22 days. Continual enrichment and culture transfer resulted in consistent demethylation of naproxen with no loss of DMN observed. Methane was generated at 0.83 mmol per 1 mmol transformed naproxen. In addition to naproxen, the consortium readily demethylated syringic acid and vanillic acid. DNA analysis revealed a community of acetogenic bacteria and syntrophic acetate oxidizing archaea. Combined with the biotransformation data, this suggests the enriched consortium performs aromatic O-demethylation through a syntrophic relationship between specific acetogens, acetate oxidizers, and methanogens. The proposed model of carbon transfer through the anaerobic food web highlights the significance of linked community interactions in the anaerobic transformation of aromatic O-methyl compounds such as naproxen.
非处方药物化合物可以作为废水处理过程中的微生物基质，也可以存在于环境中。然而，它们在降解过程中产生的代谢途径和中间产物还知之甚少。在这项研究中，我们研究了一种通过去甲基化作用代谢萘普生的厌氧废水群落。从仅以萘普生为碳源的厌氧消化物接种物中富集的培养物，在 22 天内将萘普生转化为 6-O-去甲基萘普生 (DMN)。持续的富集和培养物转移导致萘普生的持续去甲基化，没有观察到 DMN 的损失。每转化 1 毫摩尔萘普生可生成 0.83 毫摩尔甲烷。除了萘普生，该群落还很容易地去甲基化丁香酸和香草酸。DNA 分析显示出一群产乙酸细菌和协同乙酸氧化古菌。结合生物转化数据，这表明富集的群落通过特定产乙酸菌、乙酸氧化菌和产甲烷菌之间的协同关系进行芳香族 O-去甲基化。通过厌氧食物网传递碳的提议模型突出了在芳香族 O-甲基化合物（如萘普生）的厌氧转化过程中，相关群落相互作用的重要性。
