A halophilic aerobic-heterotrophic strain Halomonas venusta SND-01: Nitrogen removal by ammonium assimilation and heterotrophic nitrification-aerobic denitrification

• Published in: Bioresource technology 2023-04, Vol.374, p.128758, Article 128758
• Main Authors: Huang, Mei-Qi, Cui, You-Wei, Yang, Hou-Jian, Xu, Meng-Jiao, Cui, Yubo, Chen, Zhaobo
• Format: Article
• Language: English
• Subjects: Aerobic-heterotrophic nitrogen removal (AHNR); Aerobiosis; Ammonium assimilation; Ammonium Compounds - metabolism; Assimilatory nitrate reduction; Complete genome sequencing; Denitrification; Heterotrophic nitrification–aerobic denitrification (HN-AD); Heterotrophic Processes; Nitrates - metabolism; Nitrification; Nitrites - metabolism; Nitrogen - metabolism; Wastewater
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.128758

[Display omitted] •An aerobic-heterotrophic nitrogen removal strain was isolated from saltern sediment.•The strain removed nitrogen from high-salinity (2–10% (w/v) NaCl) wastewater.•Nitrogen removal occurred via ammonium assimilation and HN-AD processes.•The complete genome of the strain was sequenced.•A complex nitrogen metabolism network was proposed. Nitrogen (N) removal from high-salinity wastewater is a major challenge. The aerobic-heterotrophic nitrogen removal (AHNR) process has been demonstrated to be feasible for treating hypersaline wastewater. In this study, Halomonas venusta SND-01, a halophilic strain capable of performing AHNR, was isolated from saltern sediment. The strain achieved ammonium, nitrite, and nitrate removal efficiencies of 98%, 81%, and 100%, respectively. The N balance experiment suggests that this isolate removes N mainly via assimilation. Various functional genes related to N metabolism were found in the genome of the strain, establishing a complex AHNR pathway that includes ammonium assimilation, heterotrophic nitrification-aerobic denitrification, and assimilatory nitrate reduction. Four key enzymes in the N removal process were successfully expressed. The strain exhibited high-adaptability under C/N ratios of 5–15, salinities of 2%−10% (m/v), and pH of 6.5–9.5. Therefore, the strain shows high potential for treating saline wastewater with different inorganic N compositions.