1,4-Dioxane (DX) is a recalcitrant cyclic ether that has gained attention as an emerging pollutant in the aquatic environment. Enrichment of indigenous DX-degrading bacteria, which are considered to be minor populations even in DX-impacted environments, is the key for efficient biological DX removal. Therefore, this study aimed to explore carbon sources applicable for the enrichment of DX-degrading bacteria present in landfill leachate, which is a potential source of DX pollution. Microorganisms collected from landfill leachate were cultivated on six different carbon sources (DX, tetrahydrofuran (THF), 1,3,5-trioxane (TX), ethylene glycol (EG), diethylene glycol (DEG), and 1,4-butanediol (BD)) in a sequential batch mode. Consequently, enrichment cultures cultivated on THF in addition to DX improved the DX degradation ability compared to that of the original leachate sample, while those on the other test carbon sources did not. The results indicated that THF can be an alternative carbon source to enrich DX-degrading bacteria, and that TX, EG, DEG and BD are not applicable to concentrate DX-degrading bacteria in complex microbial consortia. In addition, sequencing analyses of 16S rRNA and soluble di-iron monooxygenase (SDIMO) genes revealed notable dominance of thm/dxm genes involved in group 5 SDIMO both in DX- and THF-enrichment cultures. The analysis also showed a predominance of Pseudonocardia in THF-enrichment culture, suggesting that Pseudonocardia harboring thm/dxm genes contributes to enhanced DX degradation in THF-enrichment culture.

中文翻译：

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能够使垃圾填埋场渗滤液中的1,4-二恶烷降解细菌富集的碳源。

1,4-二恶烷（DX）是一种顽固性环状醚，作为水生环境中的新兴污染物而受到关注。高效降解生物DX的关键在于，富含原生DX降解细菌的细菌即使在受到DX影响的环境中也被视为少数群体。因此，本研究旨在探索可用于富集垃圾渗滤液中存在的降解DX的细菌的碳源，垃圾渗滤液是DX污染的潜在来源。从垃圾渗滤液中收集的微生物在六种不同的碳源（DX，四氢呋喃（THF），1,3,5-三恶烷（TX），乙二醇（EG），二甘醇（DEG）和1,4-丁二醇（ BD））。所以，与原始渗滤液样品相比，除了DX之外，在THF上培养的富集培养物还改善了DX的降解能力，而其他测试碳源上的却没有。结果表明，四氢呋喃可以作为富集降解DX细菌的碳源，而TX，EG，DEG和BD不适用于浓缩复杂微生物群落中降解DX的细菌。此外，对16S rRNA和可溶性二铁单加氧酶（SDIMO）基因的测序分析表明，在DX和THF富集培养中均参与第5组SDIMO的thm / dxm基因。分析还显示占优势假诺卡氏菌在THF-富集培养物，这表明假窝藏THM / DXM基因有助于增强DX降解在THF-富集培养。