Efficient aerobic nitrate removal and nitrogen metabolism of the salt-tolerant Halomonas alkaliphila HYJ1

作者：Zimin Chai, Wei Yao, Hongwei Chen, Yiliang He, Maosheng Zheng · 发表于：Journal of Environmental Management · 年份：2025 · DOI：10.1016/j.jenvman.2025.127024 · 被引用次数：7 · 研究领域：Wastewater Treatment and Nitrogen Removal、Microbial Community Ecology and Physiology、Microbial Fuel Cells and Bioremediation

The rapid expansion of the mariculture industry has significantly increased the production of nitrogen-rich wastewater, highlighting an urgent need for more efficient treatment technologies. However, the high salinity in mariculture wastewater severely inhibits microbial metabolism, underscoring the critical necessity for introducing high-efficient salt-tolerant strains to enhance the nitrogen removal process. To address this challenge, a salt-tolerant bacterial strain, Halomonas alkaliphila HYJ1, with remarkable aerobic nitrate removal capability was successfully isolated and identified in this study. Under salinity concentration ranging from 2 % to 5 %, strain HYJ1 achieved 100 % nitrate removal efficiency within 20 h. The optimal conditions included sodium acetate as carbon source, C/N ratio of 4–8, pH 9.0, and dissolved oxygen levels of 10–30 %. The whole-genome analysis revealed that strain HYJ1 harbored key genes including narHIG , napAB, nasA , nirD , glnA , gltB , gdhA and amt , but lacked the conventional denitrifying genes responsible for reducing nitrite to N 2 , suggesting the strain employs a dissimilatory/assimilatory nitrate reduction pathway: NO-3-N → NO-2-N→ NH+ 4-N → glutamate. Transcriptional analysis further indicated that the strain accumulates abundant compatible solutes and regulates Na + /H + antiporters to resist salinity stress. Bioaugmentation tests demonstrated that strain HYJ1 significantly enhanced nitrate removal efficiency by 92.9 % within 1 h ...