Isolation and nitrogen transformation characterization of a moderately halophilic nitrification-aerobic denitrification strain <i>Halomonas</i> sp. 5505.

Zhuobin XIE; Yun WANG; Gangqiang JIANG; Yuwei LI; Wenchang LI; Yifan LIU; Zhangxiu WU; Yuanyuan HUANG; Shukun TANG

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Isolation and nitrogen transformation characterization of a moderately halophilic nitrification-aerobic denitrification strain Halomonas sp. 5505.

Author: Zhuobin XIE ¹ ; Yun WANG ¹ ; Gangqiang JIANG ² ; Yuwei LI ¹ ; Wenchang LI ¹ ; Yifan LIU ¹ ; Zhangxiu WU ¹ ; Yuanyuan HUANG ¹ ; Shukun TANG ³
Author Information

1. School of Science and Technology, Lingnan Normal University, Zhanjiang 524048, Guangdong, China.
2. Urumqi Customs Technology Center, Urumqi 830063, Xinjiang, China.
3. Yunnan Institute of Microbiology, Key Laboratory for Conservation and Utilization of Bio-Resource, and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming 650091, Yunnan, China.
Publication Type:Journal Article
Keywords: Halomonas sp. 5505; biological nitrogen removal; heterotrophic nitrification-aerobic denitrification; high-salt wastewater; nitrogen metabolism pathway
MeSH: Halomonas/classification*; Nitrogen/isolation & purification*; Denitrification; Nitrification; Wastewater/microbiology*; Aerobiosis; Biodegradation, Environmental; Salinity
From: Chinese Journal of Biotechnology 2025;41(6):2467-2482
CountryChina
Language:Chinese
Abstract: The biological nitrogen removal technology utilizing heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria has shown effectiveness in wastewater treatment. However, the nitrogen removal efficiency of HN-AD bacteria significantly decreases as the salinity increases. To tackle the challenge of treating high-salt and high-nitrogen wastewater, we isolated a moderately halophilic HN-AD strain 5505 from a salt lake in Xinjiang. The strain was identified based on morphological, physiological, and biochemical characteristics and the 16S rRNA gene sequence. Single-factor experiments were carried out with NH₄⁺-N, NO₃^--N, and NO₂^--N as sole or mixed nitrogen sources to study the nitrifying effect, denitrifying effect, and nitrogen metabolism pathway of the strain. The strain was identified as Halomonas sp.. It can grow in the presence of 1%-25% (W/V) NaCl and exhibited efficient nitrogen removal ability in the presence of 3%-8% NaCl. At the optimal NaCl concentration (8%), the strain showed the NH₄⁺-N, NO₃^--N and NO₂^--N removal rates of 100.0%, 94.11% and 74.43%, respectively. Strain 5505 removed inorganic nitrogen mainly by assimilation, which accounted for over 62.68% of total nitrogen removal. In the presence of mixed nitrogen sources, strain 5505 showed a preference for utilizing ammonia, with a potential HN-AD pathway of NH₄⁺→NH₂OH→NO₂^-→NO₃^-→NO₂^-→NO/N₂O/N₂. The findings provide efficient salt-tolerant bacterial resources, enhance our understanding of biological nitrogen removal, and contribute to the nitrogen removal efficiency improvement in the treatment of high-salt and high-nitrogen wastewater.