On December 8, 2023, Professor Hu Baolan's team from Zhejiang University published a paper titled "Methane dependent complete denitrification by a single Methanotrophic bacterium" in the journal Nature Microbiology (Impact Factor 28). After more than 1000 days of enrichment and purification cultivation, this study successfully obtained the world's first and only purified culture of a fully denitrifying anaerobic methane oxidizing bacterium, filling the gap in the coupling of methane dependent complete denitrification process in a single organism and achieving a significant breakthrough.

The core product of Changguang Chenying, the PRECI SCS-R300 Raman single-cell sorting instrument, is fortunate to provide a powerful tool for the isolation, purification, and screening of single-cell cultures after enrichment and cultivation in this study.

Abstract

Methane-dependent nitrate and nitrite removal in anoxic environments is thought to rely on syntrophy between ANME-2d archaea and bacteria in the genus 'Candidatus Methylomirabilis'. Here we enriched and purified a single Methylomirabilis from paddy soil fed with nitrate and methane, which is capable of coupling methane oxidation to nitrate reduction via nitrite to dinitrogen independently. Isotope labelling showed that this bacterium we name 'Ca. Methylomirabilis sinica' stoichiometrically performed methane-dependent complete nitrate reduction to dinitrogen gas. Multi-omics analyses collectively demonstrated that 'M. sinica' actively expressed a well-established pathway for this process, especially including nitrate reductase Nap. Furthermore, 'M. sinica' exhibited a higher nitrate affinity than most denitrifiers, implying its competitive fitness under oligotrophic nitrogen-limited conditions. Our findings revise the paradigm of methane-dependent denitrification performed by two organisms, and the widespread presence of 'M. sinica' in public databases suggests that the coupling of methane oxidation and complete denitrification in single cells substantially contributes to global methane and nitrogen budgets.

The paper links：

https://doi.org/10.1038/s41564-023-01578-6