{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T06:12:36Z","timestamp":1788502356885,"version":"build-2803163510"},"reference-count":42,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T00:00:00Z","timestamp":1788480000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"\n Sulfur-driven autotrophic denitrification (SADN) is a promising biotechnology for nitrogen removal from low-carbon wastewater; however, nitrous oxide (N\n 2<\/jats:sub>\n O) emissions remain a significant environmental concern. This study systematically investigated the effects of different nitrogen oxide electron acceptors on denitrification performance, microbial community succession, distribution of the N\n 2<\/jats:sub>\n O reductase gene\n nosZ<\/jats:italic>\n clade, and the ecological functions of\n Thiobacillus<\/jats:italic>\n using sequential enrichment cultivation. Among the tested conditions, the nitrate (\n \n \n \n \n NO<\/mml:mtext>\n <\/mml:mrow>\n \n 3<\/mml:mn>\n <\/mml:mrow>\n \n -<\/mml:mo>\n <\/mml:mrow>\n <\/mml:msubsup>\n <\/mml:math>\n <\/jats:inline-formula>\n )-fed system achieved the highest denitrification and sulfur oxidation rates, with the lowest net N\n 2<\/jats:sub>\n O accumulation, whereas the nitrite (\n \n \n \n \n NO<\/mml:mtext>\n <\/mml:mrow>\n \n 2<\/mml:mn>\n <\/mml:mrow>\n \n -<\/mml:mo>\n <\/mml:mrow>\n <\/mml:msubsup>\n <\/mml:math>\n <\/jats:inline-formula>\n )-fed condition led to severe N\n 2<\/jats:sub>\n O accumulation due to an imbalance between N\n 2<\/jats:sub>\n O production and reduction. High-throughput sequencing and quantitative PCR analyses revealed that\n Thiobacillus<\/jats:italic>\n became the primary sulfur-oxidizing denitrifier in the presence of\n \n \n \n \n NO<\/mml:mtext>\n <\/mml:mrow>\n \n 3<\/mml:mn>\n <\/mml:mrow>\n \n -<\/mml:mo>\n <\/mml:mrow>\n <\/mml:msubsup>\n <\/mml:math>\n <\/jats:inline-formula>\n ,\n \n \n \n \n NO<\/mml:mtext>\n <\/mml:mrow>\n \n 2<\/mml:mn>\n <\/mml:mrow>\n \n -<\/mml:mo>\n <\/mml:mrow>\n <\/mml:msubsup>\n <\/mml:math>\n <\/jats:inline-formula>\n , and nitric oxide, accompanied by substantial enrichment of\n nirS<\/jats:italic>\n and clade I\n nosZ<\/jats:italic>\n genes. In contrast, N\n 2<\/jats:sub>\n O-fed conditions promoted a more functionally diverse community enriched with clade II\n nosZ<\/jats:italic>\n bacteria, including\n Azonexus<\/jats:italic>\n and\n Dechloromonas<\/jats:italic>\n . Metagenomic analyses recovered three distinct\n Thiobacillus<\/jats:italic>\n metagenome-assembled genomes (MAGs 10, 11, and 25), each with distinct denitrification and sulfur oxidation capacities. MAG 10 contains genes for complete sulfur oxidation and denitrification, including clade I\n nosZ<\/jats:italic>\n and\n nirS<\/jats:italic>\n genes. Conversely, the\n nosZ<\/jats:italic>\n gene was not detected in MAG 11, whereas the\n norB\/norC<\/jats:italic>\n genes were present, indicating their potential role as an N\n 2<\/jats:sub>\n O producer. MAG 25 exhibits N\n 2<\/jats:sub>\n O-responsive functional enrichment upon N\n 2<\/jats:sub>\n O feeding, reflecting a specialized ecological strategy centered on sulfur oxidation coupled with N\n 2<\/jats:sub>\n O reduction. Overall, these findings show that electron acceptors play a key role in shaping microbial succession,\n nosZ<\/jats:italic>\n clade distribution, and the dual roles of\n Thiobacillus<\/jats:italic>\n in N\n 2<\/jats:sub>\n O cycling depending on conditions. This study provides new insights into microbial ecology and offers potential strategies for mitigating N\n 2<\/jats:sub>\n O emissions in SADN processes.\n <\/jats:p>","DOI":"10.3389\/fmicb.2026.1903473","type":"journal-article","created":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T05:29:21Z","timestamp":1788499761000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Electron acceptor-dependent duality of nitrous oxide metabolism in Thiobacillus during sulfur autotrophic denitrification"],"prefix":"10.3389","volume":"17","author":[{"given":"Muchun","family":"Zhou","sequence":"first","affiliation":[{"name":"Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shohei","family":"Yasuda","sequence":"additional","affiliation":[{"name":"Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway","place":["Galway, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hiroto","family":"Miura","sequence":"additional","affiliation":[{"name":"Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tianxiang","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Megumi","family":"Kuroiwa","sequence":"additional","affiliation":[{"name":"Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoguang","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Environment, Nanjing Normal University","place":["Nanjing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akihiko","family":"Terada","sequence":"additional","affiliation":[{"name":"Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,4]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"129950","DOI":"10.1016\/j.biortech.2023.129950","article-title":"Nitrous oxide emissions in novel wastewater treatment processes: a comprehensive review","volume":"391","author":"An","year":"2024","journal-title":"Bioresour. 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