Microbial selenite reduction coupled to anaerobic oxidation of methane

• Published in: The Science of the total environment Vol. 669; pp. 168 - 174
• Main Authors: Bai, Ya-Nan, Wang, Xiu-Ning, Lu, Yong-Ze, Fu, Ling, Zhang, Fang, Lau, Tai-Chu, Zeng, Raymond J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.06.2019
• Subjects: Anaerobiosis; Bacteria - metabolism; DAMO; Denitrification; Methane - metabolism; Methane oxidation; Microbial community; Microscopy, Electron, Scanning; Nitrate; Oxidation-Reduction; Photoelectron Spectroscopy; RNA, Bacterial - analysis; RNA, Ribosomal, 16S - analysis; Selenious Acid - metabolism; Selenite reduction; Sequence Analysis, RNA; DAMO; Nitrate; Methane oxidation; Microbial community; Selenite reduction
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.03.119

Denitrifying anaerobic methane oxidation (DAMO) is the process of coupling the anaerobic oxidation of methane (AOM) with denitrification, which plays an important part in controlling the flow of methane in anoxic niches. In this study, we explored the feasibility of microbial selenite reduction using methane by DAMO culture. Isotopic 13CH4 and long-term experiments showed that selenite reduction was coupled to methane oxidation, and selenite was ultimately reduced to Se (0) by the analyses of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The introduction of nitrate, the original electron acceptor in the DAMO culture, inhibited selenite reduction. Meanwhile, the microbial community of DAMO culture was significantly changed when the electron acceptor was changed from nitrate to selenite after long-term selenite reduction. High-throughput 16S rRNA gene sequencing indicated that Methylococcus (26%) became the predominant microbe performing selenite reduction and methane oxidation and the possible pathways of AOM accompanied with selenite reduction were proposed. This study revealed more potential relation during the biogeochemical cycle of carbon, nitrogen, and selenium. [Display omitted] •Selenite can be reduced to Se (0) coupled with methane oxidation.•Selenite reduction is inhibited by nitrate, the original electron acceptor of DAMO.•The abundance of DAMO microbes decrease when selenite reduction is performed.•Methylococcus (26%) becomes the predominant microbe in the system.•The possible pathways of AOM accompanied with selenite reduction are proposed.