Pseudomonas oryzihabitans EN-F4菌株的脱氮特征及羟胺对其脱氮过程的促进作用

Nitrogen removal characteristics of Pseudomonas oryzihabitans EN-F4 with/without the supplementation of hydroxylamine

摘要:

【目的】异养硝化-好氧反硝化（heterotrophic nitrification-aerobic denitrification，HN-AD）微生物在生物脱氮中具有重要作用，而能同时去除废水中多种无机氮尤其是羟胺的HN-AD微生物报道较少。本研究从菜地中分离筛选出一株能同时去除羟胺和亚硝酸盐的HN-AD菌株EN-F4，探究其脱氮特征以及羟胺对其脱氮过程的影响，为提高废水处理效率奠定基础。【方法】通过形态学和16S rRNA基因测序对该菌株进行鉴定，并利用批量试验研究该菌株的脱氮特征，结合氮平衡、酶活性和特异性酶抑制剂探索菌株的HN-AD机理，最后通过添加羟胺研究其对不同氮源转化的影响。【结果】菌株EN-F4经鉴定为栖稻假单胞菌（Pseudomonas oryzihabitans），该菌株在25℃条件下对铵盐、羟胺、亚硝酸盐和硝酸盐的去除效率分别为99.27%、99.13%、87.01%和85.20%，对应的最大去除速率分别为8.27、1.85、5.10和5.31 mg/（L·h）。更突出的是，外加羟胺后不会抑制该菌的反硝化能力，反而促进了亚硝酸盐和总氮的去除，其最大去除速率分别提升至7.80 mg/（L·h）和7.51 mg/（L·h）。结合酶活性的成功检测、氮平衡和HN-AD特异性酶抑制剂分析证实了菌株具有优异的HN-AD能力。【结论】菌株Pseudomonas oryzihabitans EN-F4可以在25℃条件下高效地进行HN-AD去除废水中的多种无机氮，且羟胺能显著促进亚硝酸盐和总氮的去除。

Abstract:

[Objective] The microorganisms with the function of heterotrophic nitrification-aerobic denitrification (HN-AD) play a key role in the biological removal of nitrogen, while little is known about the HN-AD microorganisms capable of simultaneous removing multiple inorganic nitrogen sources, especially hydroxylamine, from wastewater. In this study, a HN-AD strain EN-F4 capable of simultaneous removing hydroxylamine and nitrite was isolated from a vegetable field. We explored its nitrogen removal characteristics and the effects of hydroxylamine on the nitrogen conversion process, aiming to lay a foundation for improving the efficiency of wastewater treatment. [Methods] The strain EN-F4 was identified based on morphological characteristics and 16S rRNA gene sequence. Batch experiments were carried out to determine the nitrogen conversion characteristics of the strain EN-F4. The nitrogen balance, enzyme activity, and specific enzyme inhibitor tests were conducted to decipher the HN-AD mechanism of the strain EN-F4. Finally, the effects of hydroxylamine addition on the conversion of different nitrogen sources were explored. [Results] The isolate EN-F4 was identified as Pseudomonas oryzihabitans. The strain cultured at 25℃ showed the ammonium, hydroxylamine, nitrite, and nitrate removal efficiencies of 99.27%, 99.13%, 87.01%, and 85.20% and the maximum nitrogen removal rates of 8.27, 1.85, 5.10, and 5.31 mg/(L·h), respectively. The addition of hydroxylamine did not inhibit the denitrifying ability of the strain EN-F4, while it promoted the removal of nitrite and total nitrogen by the strain, with the maximum removal rates reaching 7.80 and 7.51 mg/(L·h), respectively. The enzyme activity, nitrogen balance, and specific enzyme inhibitors confirmed the strong HN-AD capability of the strain. [Conclusion] Pseudomonas oryzihabitans EN-F4 could efficiently remove inorganic nitrogen sources from wastewater by HN-AD at 25℃, and hydroxylamine could significantly promote the removal of nitrite and total nitrogen.