Carbon sources that enable enrichment of 1,4-dioxane-degrading bacteria in landfill leachate
- 1 Downloads
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.
KeywordsCarbon source 1,4-Dioxane-degrading bacteria Enrichment Landfill leachate Soluble di-iron monooxygenase thm/dxm genes
This study was partially supported by JSPS KAKENHI Grant Numbers JP16K12624 and JP19H04301.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Amann RI, Ludwig W, Schleiter KH (1995) Phylogenetic identification and in situ detection of individual microbial cells without cultivation. Microbiol Rev 59:143–169Google Scholar
- Aoyagi T, Morishita F, Sugiyama Y, Ichikawa D, Mayumi D, Kikuchi Y, Ogata A, Muraoka K, Habe H, Hori T (2018) Identification of active and taxonomically diverse 1,4-dioxane degraders in a full-scale activated sludge system by high-sensitivity stable isotope probing. ISME J 12:2376–2388CrossRefGoogle Scholar
- Caporaso JG, Kuczynski J, Stombaugh J, Bittinger K, Bushman FD, Costello EK, Fierer N, Peña AG, Goodrich JK, Gordon JI, Huttley GA, Kelley ST, Knights D, Koenig JE, Ley RE, Lozupone CA, McDonald D, Muegge BD, Pirrung M, Reeder J, Sevinsky JR, Turnbaugh PJ, Walters WA, Widmann J, Yatsunenko T, Zaneveld J, Knight R (2010) QIIME allows analysis of high-throughput community sequencing data. Nat Methods 7:335–336CrossRefGoogle Scholar
- International Agency for Research on Cancer (IARC) (1999) 1,4-Dioxane. In: IARC monographs on the evaluation of carcinogenic risks to humans, vol. 71, Re-evaluation of some organic chemicals, hydrazine and hydrogen peroxide. IARC, Lyon, pp. 589–602Google Scholar
- Li M, Mathieu J, Liu Y, Van Orden ET, Yang Y, Fiorenza S, Alvarez PJJ (2014) The abundance of tetrahydrofuran/dioxane monooxygenase genes (thmA/dxmA) and 1,4-dioxane degradation activity are significantly correlated at various impacted aquifers. Environ Sci Technol Lett 1:122–127CrossRefGoogle Scholar
- Parales RE, Adamus JE, White N, May HD (1994) Degradation of 1,4-dioxane by an actinomycete in pure culture. Appl Environ Microbiol 60:4527–4530Google Scholar
- Wang B, Teng Y, Xu Y, Chen W, Ren W, Li Y, Christie P, Luo Y (2018) Effect of mixed soil microbiomes on pyrene removal and the response of the soil microorganisms. Sci Total Environ 640–641:9–17Google Scholar
- White GF, Russell NJ, Tidswell EC (1996) Bacterial scission of ether bonds. Microbiol Rev 60:216–232Google Scholar