Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Feb 20:912:168953.
doi: 10.1016/j.scitotenv.2023.168953. Epub 2023 Dec 11.

Metagenomics coupled with thermodynamic analysis revealed a potential way to improve the nitrogen removal efficiency of the aerobic methane oxidation coupled to denitrification process under the hypoxic condition

Xingkun Xu  1 , Weixiang Wu  2 , Xinyu Li  1 , Changxun Zhao  1 , Yong Qin  3
Affiliations

Metagenomics coupled with thermodynamic analysis revealed a potential way to improve the nitrogen removal efficiency of the aerobic methane oxidation coupled to denitrification process under the hypoxic condition

Xingkun Xu et al. Sci Total Environ. .

Abstract

Aerobic methane (CH4) oxidation coupled to denitrification (AME-D) is a promising wastewater treatment process for CH4 utilization and nitrogen removal. However, it is unclear which CH4-derived carbons are suitable for the AME-D process and how these organics are metabolized. In this study, metagenomics coupled with a thermodynamic model were used to explore the microorganisms and their metabolic mechanisms in an AME-D membrane biofilm reactor (MBfR) with high nitrogen removal efficiency. Results revealed that the aerobic methanotrophs of Methylomonas with the CH4-based fermentation potential were highly enriched and played an important role in CH4 conversion in the MBfR. Bacteria of Xanthomonadaceae, Methylophilaceae, Bacteroidetes, Rhodocyclaceae, Hyphomicrobium were the main denitrifiers. C1 compounds (methanol, formaldehyde and formate) and CH4-based fermentation products are promising cross-feeding intermediates of the AME-D. Specially, by means of integrating the CH4-based fermentation with denitrification, the minimum amount of CH4 required to remove per mole of nitrate can be further reduced to 1.25 mol-CH4 mol-1-NO3-, even lower than that of methanol. Compared to the choice to secrete methanol, type I aerobic methanotrophs require a 15 % reduction in the amount of oxygen required to secrete fermentation metabolites, but a 72 % increase in the amount of CH4-C released. Based on this trade-off, optimizing oxygen supply strategies will help to construct engineered microbiomes focused on aerobic methanotrophs with CH4-based fermentation potential. This study gives an insight into C and N conversions in the AME-D process and highlights the role of CH4-based fermentation in improving the nitrogen removal efficiency of the AME-D process.

Keywords: Aerobic methanotroph; Denitrifier; Membrane biofilm reactor; Microbial mechanism.

PubMed Disclaimer

Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

LinkOut - more resources