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Background <p>The rapid expansion of the aquaculture industry has intensified the discharge of nitrogen-rich wastewater, posing significant ecological risks. Biological treatment with HN-AD bacteria is sustainable, but most conventional strains lack long-term environmental resilience. The key bottleneck is identifying novel, robustly adaptable strains, especially spore-forming Gram-positive bacteria. Moreover, the non-canonical metabolic mechanisms that distinguish such strains remain largely unexplored. This study isolated a novel HN-AD strain, <i>Paenibacillus glycanilyticus</i> DQ-1, from aquaculture sludge and investigated its nitrogen removal performance and genomic metabolic pathways.</p> Methods <p>Strain DQ-1 was isolated and identified through 16&#xa0;S rRNA gene sequencing and morphological analysis. Its nitrogen removal efficiency was evaluated under aerobic conditions with different nitrogen sources, including ammonium nitrogen (NH₄<sup>+</sup>-N), nitrate nitrogen (NO₃<sup>−</sup>-N), total inorganic nitrogen (TIN) and hydroxylamine nitrogen (NH<sub>2</sub>OH-N). Whole-genome sequencing was conducted using the PacBio Sequel II platform to identify functional genes and reconstruct the nitrogen metabolic pathways.</p> Results <p>Strain DQ-1 achieved 93.26% NH₄⁺-N and 100% NO₃⁻-N removal within 36&#xa0;h, with 95.92% TIN removal. Genomic analysis revealed a complete assimilatory nitrate reduction pathway (<i>nasAB</i> and <i>nirBD</i>). Notably, while the canonical hydroxylamine oxidoreductase gene (<i>hao</i>) is absent, the strain showed 74.67% NH<sub>2</sub>OH-N removal and harbors a putative ammonia monooxygenase gene (<i>amo</i>). These results suggest that DQ-1 employs a novel non-canonical pathway, distinct from known HN-AD models, for efficient nitrogen transformation.</p> Conclusions <p><i>P. glycanilyticus</i> DQ-1 differs from typical HN-AD bacteria in its spore-forming ability and a novel <i>hao</i>-independent pathway. This study provides the first comprehensive genomic insight into the nitrogen removal capacity of <i>P. glycanilyticus</i>, expanding the microbial resource pool for sustainable environmental remediation.</p>

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A novel HN-AD strain Paenibacillus glycanilyticus DQ-1 with high-efficiency nitrogen removal capacity: genomic insights into its nitrogen metabolic mechanism

  • 期刊论文

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  • 发表日期：

    2026年5月19日

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  • Le-Nan Shi,
  • Yang-gang Han,
  • Hai Liang,
  • Tiejun Li,
  • Hui Shi,
  • Lei Jin

摘要

Background

The rapid expansion of the aquaculture industry has intensified the discharge of nitrogen-rich wastewater, posing significant ecological risks. Biological treatment with HN-AD bacteria is sustainable, but most conventional strains lack long-term environmental resilience. The key bottleneck is identifying novel, robustly adaptable strains, especially spore-forming Gram-positive bacteria. Moreover, the non-canonical metabolic mechanisms that distinguish such strains remain largely unexplored. This study isolated a novel HN-AD strain, Paenibacillus glycanilyticus DQ-1, from aquaculture sludge and investigated its nitrogen removal performance and genomic metabolic pathways.

Methods

Strain DQ-1 was isolated and identified through 16 S rRNA gene sequencing and morphological analysis. Its nitrogen removal efficiency was evaluated under aerobic conditions with different nitrogen sources, including ammonium nitrogen (NH₄+-N), nitrate nitrogen (NO₃−-N), total inorganic nitrogen (TIN) and hydroxylamine nitrogen (NH2OH-N). Whole-genome sequencing was conducted using the PacBio Sequel II platform to identify functional genes and reconstruct the nitrogen metabolic pathways.

Results

Strain DQ-1 achieved 93.26% NH₄⁺-N and 100% NO₃⁻-N removal within 36 h, with 95.92% TIN removal. Genomic analysis revealed a complete assimilatory nitrate reduction pathway (nasAB and nirBD). Notably, while the canonical hydroxylamine oxidoreductase gene (hao) is absent, the strain showed 74.67% NH2OH-N removal and harbors a putative ammonia monooxygenase gene (amo). These results suggest that DQ-1 employs a novel non-canonical pathway, distinct from known HN-AD models, for efficient nitrogen transformation.

Conclusions

P. glycanilyticus DQ-1 differs from typical HN-AD bacteria in its spore-forming ability and a novel hao-independent pathway. This study provides the first comprehensive genomic insight into the nitrogen removal capacity of P. glycanilyticus, expanding the microbial resource pool for sustainable environmental remediation.