近日，南丹麦大学Beate Kraft等研究人员发现，氨氧化古菌可产生氧气和氮。相关论文于2022年1月6日发表在《科学》杂志上。

通过进行氧气浓度被稀释到纳摩尔范围的培养，研究人员表明，在氧气耗尽后，海洋氨氧化古菌（Nitrosopumilus maritimus）能够产生二氮和氧气，用于氨的氧化。该途径尚未完全解析，但可能有一氧化氮和一氧化二氮作为关键的中间产物。海洋氨氧化古菌成为了少数已知能在黑暗中产生氧气的生物体。基于这种能力，研究人员重新评估了海洋氨氧化古菌在缺氧海洋环境中的作用。

据悉，氨氧化古菌（AOA）是世界海洋中最丰富的微生物群体之一，是氮循环中的关键角色。它们的能量代谢（将氨氧化成亚硝酸盐）需要氧气。然而，在无法检测到氧气的环境中，AOA也很丰富。

附：英文原文

Title: Oxygen and nitrogen production by an ammonia-oxidizing archaeon

Author: Beate Kraft, Nico Jehmlich, Morten Larsen, Laura A. Bristow, Martin Knneke, Bo Thamdrup, Donald E. Canfield

Issue&Volume: 2022-01-07

Abstract: Ammonia-oxidizing archaea (AOA) are one of the most abundant groups of microbes in the world’s oceans and are key players in the nitrogen cycle. Their energy metabolism—the oxidation of ammonia to nitrite—requires oxygen. Nevertheless, AOA are abundant in environments where oxygen is undetectable. By carrying out incubations for which oxygen concentrations were resolved to the nanomolar range, we show that after oxygen depletion, Nitrosopumilus maritimus produces dinitrogen and oxygen, which is used for ammonia oxidation. The pathway is not completely resolved but likely has nitric oxide and nitrous oxide as key intermediates. N. maritimus joins a handful of organisms known to produce oxygen in the dark. On the basis of this ability, we reevaluate the role of N. maritimus in oxygen-depleted marine environments.

DOI: abe6733

Source: https://www.science.org/doi/10.1126/science.abe6733