Aerobic ammonia and nitrite oxidation reactions are fundamental biogeochemical reactions contributing to the global nitrogen cycle. Although aerobic nitrite oxidation yields 4.8-folds less Gibbs free energy (∆G_r) than aerobic ammonia oxidation in the NH₄⁺-feeding marine recirculating trickling biofilter reactors operated in the present study, nitrite-oxidizing and not ammonia-oxidizing Nitrospira (sublineage IV) outnumbered ammonia-oxidizing Nitrosomonas (relative abundance; 53.8% and 7.59% respectively). CO₂ assimilation efficiencies during ammonia or nitrite oxidation were 0.077 μmol-¹⁴CO₂/μmol-NH₃ and 0.053–0.054 μmol-¹⁴CO₂/μmol-NO₂⁻ respectively, and the difference between ammonia and nitrite oxidation was much smaller than the difference of ∆G_r. Free-energy efficiency of nitrite oxidation was higher than ammonia oxidation (31%–32% and 13% respectively), and high CO₂ assimilation and free-energy efficiencies were a determinant for the dominance of Nitrospira over Nitrosomonas. Washout of Nitrospira and Nitrosomonas from the trickling biofilter reactors was also examined by quantitative PCR assay. Normalized copy numbers of Nitrosomonas amoA were 1.5- to 1.7-folds greater than Nitrospira nxrB and 16S rRNA gene in the reactor effluents. Nitrosomonas was more susceptible for washout than Nitrospira in the trickling biofilter reactors, which was another determinant for the dominance of Nitrospira in the trickling biofilter reactors.

中文翻译：

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海洋再循环滴流生物滤池反应器中亚硝酸盐氧化亚硝化螺菌和氨氧化亚硝化单胞菌的生长

好氧氨和亚硝酸盐氧化反应是有助于全球氮循环的基本生物地球化学反应。_{尽管在本研究中运行的 NH 4} ^{+进料海洋再循环滴流生物滤池反应器中，有氧亚硝酸盐氧化产生的吉布斯自由能 (} ΔG _r ) 比有氧氨氧化低 4.8 倍，但亚硝酸盐氧化而非氨氧化Nitrospira（亚系IV) 数量超过氨氧化亚硝化单胞菌（相对丰度；分别为 53.8% 和 7.59%）。氨或亚硝酸盐氧化过程中的CO ₂同化效率为 0.077 μmol- ¹⁴ CO ₂ /μmol-NH ₃和0.053-0.054 μmol- ¹⁴ CO ₂ /μmol-NO ₂ ^-，氨和亚硝酸盐氧化的差异远小于ΔG _r的差异。亚硝酸盐氧化的自由能效率高于氨氧化（分别为 31%–32% 和 13%），高 CO ₂同化和自由能效率是Nitrospira优于Nitrosomonas的决定因素。还通过定量 PCR 测定检查了从滴流生物过滤器反应器中冲洗掉的Nitrospira和Nitrosomonas 。亚硝化单胞菌 amoA的标准化拷贝数比反应器流出物中的Nitrospira nxrB和 16S rRNA 基因高 1.5 到 1.7 倍。Nitrosomonas比Nitrospira在滴流生物过滤器反应器中更容易被冲刷，这是Nitrospira在滴流生物过滤器反应器中占主导地位的另一个决定因素。