Candidatus "Methylomirabilis oxyfera" is a candidate species of Gram-negative bacteria belonging to the NC10 phylum, characterized for its capacity to couple anaerobic methane oxidation with nitrite reduction in anoxic environments.

"M. oxyfera" has been identified in several environments including rice paddy soil in China,[7] multiple river and lake sediments,[8] and wastewater sludge in The Netherlands.

"M. oxyfera" is predicted to inhabit environments with high concentrations of nitrogen and methane, near boundaries that separate oxic and anoxic zones.

These organisms may also play a role in reducing the nutrient loads within freshwater ecosystems that have been contaminated with fertilizers.

[8] Nitrites are usually undesirable in the environment, can be detrimental to human health, and can lead to eutrophication of aquatic ecosystems and algal blooms.