以亚硝氮为唯一氮源生长的海洋紫色硫细菌去除无机三态氮

Inorganic nitrogen removal by a marine purple sulfur bacterium capable of growth on nitrite as sole nitrogen source

【目的】揭示以亚硝氮为唯一氮源生长的海洋紫色硫细菌去除水体中无机三态氮的特征和规律。【方法】在光照厌氧环境下,以乙酸盐为唯一有机物,在分别以氨氮、亚硝态氮、硝态氮为唯一氮源和三氮共存的模拟水体中,采用Nessler’s试剂分光光度法、N-(1-萘基)-乙二胺分光光度法和紫外分光光度法分别测定水体中氨氮、亚硝态氮和硝态氮的含量,比浊法测定菌体生物量。【结果】随着时间的延长,海洋紫色硫细菌Marichromatium gracile YL28分别在氨氮、亚硝态氮和硝态氮为唯一氮源的水体中对三氮的去除量增加,生物量增大,水体pH升高,并逐渐趋于平衡;YL28对氨氮的最大去除量和最大耐受浓度分别为9.64 mmol/L和36.64 mmol/L,当氨氮浓度低于3.21 mmol/L时,去除率可达97.61%以上;与氨氮相比,以亚硝态氮和硝态氮为唯一氮源,菌体的生长速率、生物量和水体最终pH较低,但对亚硝态氮和硝态氮的去除速率和去除量仍然很高,当亚硝态氮和硝态氮浓度分别达13.50 mmol/L和22.90 mmol/L时,YL28仍能够完全去除。在三氮共存的水体中,YL28也能良好的去除无机三态氮,对亚硝态氮和硝态氮去除能力更强。【结论】在模拟水体中,海洋紫色硫细菌YL28能够分别以氨氮、亚硝态氮和硝态氮为唯一氮源生长,具有良好的耐受和去除无机三态氮的能力,尤其对亚硝态氮具有良好的去除能力。本研究为进一步开发高效脱氮,尤其是去除亚硝态氮的不产氧光合细菌水质调节剂奠定了基础,也为微生物制剂的合理应用提供参考。

[Objective] To clarify the removal of ammonium, nitrate and nitrite by a marine purple sulfur bacterium capable of growing on nitrite as sole nitrogen source. [Methods] Ammonium, nitrate and nitrite concentration in simulated wastewater were determined using the Nessler＇s reagent spectrophotometry, N-（1-naphthyl）-1,2-diaminoethane dihydrochloride spectrophotometry, UVspectrophotometry, respectively. [Results] The removal of ammonium, nitrate and nitrite as well as bacterial biomass and pH increased with time, and then tended to equilibrium. Strain YL28 exhibited effective ammonium removal ability, with a maximal removal and tolerance of 9.64 mmol/L and 36.64 mmol/L, respectively. The removal rate exceeded 97.61% when the concentration of ammonium was less than 3.21 mmol/L. Compared to ammonium, the cell growth rate, biomass and pH of wastewater enhanced slowly while using nitrate and nitrite as sole nitrogen source. However, the removal of nitrate and nitrite were higher than that of ammonium. Nitrate and nitrite in wastewater could be completely removed when their concentrations were up to 13.50 mmol/L and 22.90 mmol/L, respectively. When the three inorganic nitrogen existed simultaneously in wastewater, ammonium, nitrate and nitrate could be removed by strain YL28, the removal of nitrate and nitrite was higher than that of ammonium. [Conclusion] Strain YL28 would be a promising candidate for bioremediation of polluted aquaculture wastewater, especially for nitrite-polluted marine culture wastewater.