Heterotrophic nitrification by Alcaligenes faecalis links organic and inorganic nitrogen metabolism

作者：Yaling Qin, Zonglin Liang, Guomin Ai, Weifeng Liu, Yong Tao, Cheng‐Ying Jiang, Shuang‐Jiang Liu, De‐Feng Li · 发表于：The ISME Journal · 年份：2024 · DOI：10.1093/ismejo/wrae174 · 被引用次数：29 · 研究领域：Wastewater Treatment and Nitrogen Removal、Nitric Oxide and Endothelin Effects、Neutrophil, Myeloperoxidase and Oxidative Mechanisms

Heterotrophic nitrification remains a mystery for decades. It has been commonly hypothesized that heterotrophic nitrifiers oxidize ammonia to hydroxylamine and then to nitrite in a way similar to autotrophic AOA and AOB. Recently, heterotrophic nitrifiers from Alcaligenes were found to oxidize ammonia to hydroxylamine and then to N2 ("dirammox", direct ammonia oxidation) by the gene cluster dnfABC with a yet-to-be-reported mechanism. The role of a potential glutamine amidotransferase DnfC clues the heterotrophic ammonia oxidation might involving in glutamine. Here, we found Alcaligenes faecalis JQ135 could oxidize amino acids besides ammonia. We discovered that glutamine is an intermediate of the dirammox pathway and the glutamine synthetase gene glnA is essential for both A. faecalis JQ135 and the Escherichia coli cells harboring dnfABC gene cluster to oxidize amino acids and ammonia. Our study expands understanding of heterotrophic nitrifiers and challenges the classical paradigm of heterotrophic nitrification.