Scholarlink

<p>Low temperature can suppress biological nitrogen removal (BNR) efficiency. Although nitrogen removal (NR) characteristics of single psychrotolerant bacteria have been extensively studied, synergistic interactions between functionally distinct psychrotolerant nitrogen-removing consortia remain unexplored. In this study, a composite microbial agent, designated NDC-6, was generated by coculturing a psychrotolerant nitrifying consortium NC1 (<i>Pseudomonas veronii</i> HN1, <i>P. poae</i> HN2, and <i>P. peli</i> HN3) and an aerobic denitrifying consortium DC1 (<i>Aeromonas</i> sp. AD1, <i>P. extremaustralis</i> AD2, and <i>Serratia liquefaciens</i> AD3) at a 1:1 inoculation ratio, and its NR performance was systematically evaluated. After 3 days of incubation at 10&#xa0;°C, NDC-6 achieved removal efficiencies of 89.3%, 88.1%, 85.5%, and 95.3% for NH<sub>4</sub><sup>+</sup>-N, NO<sub>3</sub><sup>−</sup>-N, total nitrogen (TN), and chemical oxygen demand (COD), which were significantly higher than those of individual strains or single-function consortia. Sodium succinate was identified as the optimal carbon source, which simultaneously improved biomass growth and NR efficacy of NDC-6. Optimal culture conditions determined using response surface methodology were as follows: C/N ratio, 6; temperature, 10.2&#xa0;°C; pH, 7.2; and shaking speed, 156&#xa0;rpm. Under these conditions, the verification experiment achieved a TN removal efficiency of 89.8%, closely approaching the theoretically predicted maximum of 90.2%. Nitrogen balance and functional gene (<i>hao</i>, <i>nap</i>A, <i>nir</i>S, <i>nir</i>K, <i>cnor</i>B, and <i>nos</i>Z) expression analyses revealed that under low-temperature and aerobic conditions, NDC-6 achieved NR primarily through dual pathways of bacterial assimilation and dissimilation, converting NH<sub>4</sub><sup>+</sup>-N and NO<sub>3</sub><sup>−</sup>-N into intracellular nitrogen and N<sub>2</sub>. The dissimilatory mechanism relied on synergistic metabolism and functional complementation between NC1 and DC1, mediated by their respective functional genes. This study provides mechanistic insights into the biological treatment of nitrogen-containing wastewater, particularly under low-temperature conditions, and offers a novel strategy for such treatment.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Development of a psychrotolerant composite microbial agent for nitrogen removal and its nitrogen metabolism pathways

  • 期刊论文

  • 发表日期：

    2026年1月8日

查看全文
  • Yihua Dong,
  • Jing Xu,
  • Feng Chen,
  • Liang Li,
  • Guangsheng Qian,
  • Peng Zhang

摘要

Low temperature can suppress biological nitrogen removal (BNR) efficiency. Although nitrogen removal (NR) characteristics of single psychrotolerant bacteria have been extensively studied, synergistic interactions between functionally distinct psychrotolerant nitrogen-removing consortia remain unexplored. In this study, a composite microbial agent, designated NDC-6, was generated by coculturing a psychrotolerant nitrifying consortium NC1 (Pseudomonas veronii HN1, P. poae HN2, and P. peli HN3) and an aerobic denitrifying consortium DC1 (Aeromonas sp. AD1, P. extremaustralis AD2, and Serratia liquefaciens AD3) at a 1:1 inoculation ratio, and its NR performance was systematically evaluated. After 3 days of incubation at 10 °C, NDC-6 achieved removal efficiencies of 89.3%, 88.1%, 85.5%, and 95.3% for NH4+-N, NO3−-N, total nitrogen (TN), and chemical oxygen demand (COD), which were significantly higher than those of individual strains or single-function consortia. Sodium succinate was identified as the optimal carbon source, which simultaneously improved biomass growth and NR efficacy of NDC-6. Optimal culture conditions determined using response surface methodology were as follows: C/N ratio, 6; temperature, 10.2 °C; pH, 7.2; and shaking speed, 156 rpm. Under these conditions, the verification experiment achieved a TN removal efficiency of 89.8%, closely approaching the theoretically predicted maximum of 90.2%. Nitrogen balance and functional gene (hao, napA, nirS, nirK, cnorB, and nosZ) expression analyses revealed that under low-temperature and aerobic conditions, NDC-6 achieved NR primarily through dual pathways of bacterial assimilation and dissimilation, converting NH4+-N and NO3−-N into intracellular nitrogen and N2. The dissimilatory mechanism relied on synergistic metabolism and functional complementation between NC1 and DC1, mediated by their respective functional genes. This study provides mechanistic insights into the biological treatment of nitrogen-containing wastewater, particularly under low-temperature conditions, and offers a novel strategy for such treatment.