Nitrogen removal capability and mechanism of a novel heterotrophic nitrification–aerobic denitrification bacterium Halomonas sp. DN3

• Published in: Bioresource technology Vol. 387; p. 129569
• Main Authors: Xie, Yumeng, Tian, Xiangli, He, Yu, Dong, Shuanglin, zhao, Kun
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2023
• Subjects: Denitrification; Genome analysis; Nitrification; Nitrogen assimilation; Nitrogen removal; Nitrogen removal; Denitrification; Genome analysis; Nitrogen assimilation; Nitrification
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129569

[Display omitted] •Significant removal capability of inorganic N was detected in strain DN3.•N assimilation dominated the NH4+-N, NO3−-N, and NO2−-N removal process.•Hetertrophic nitrification pathway of DN3 was revealed: NH4+ → NH2OH → NO → N2O → N2.•N eliminating assays under various conditions showed bacterial potential application.•A candidate for treatment of mariculture wastewater was provided by this work. Recently, the functional microorganisms capable of eliminating nitrogenous waste have been applied in mariculture systems. As a potential candidate for treating mariculture wastewater, strain DN3 eliminated 100% of ammonia and nitrate and 96.61%–100% of nitrite within 72 h, when single nitrogen sources at concentrations of 0–50 mg/L. Strain DN3 also exhibited the efficient removal performance of mixed-form nitrogen (ammonia, nitrate, and nitrite) at salinity 30 ‰, C/N ratio 20, and 180 rpm. The nitrogen assimilation pathway dominated inorganic nitrogen metabolism, with less nitrogen (14.23%-25.02% of TN) lost into the air via nitrification and denitrification, based on nitrogen balance analysis. Moreover, the bacterial nitrification pathway was explored by enzymatic assays and inhibition assays. These complex nitrogen assimilation and dissimilation processes were further revealed by bacterial genome analysis. These results provide important insight into nitrogen metabolism of Halomonas sp. and theoretical support for treating mariculture wastewater with strain DN3.