Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting
Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting
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DOI：
10.1002/(sici)1097-0290(20000520)68:4
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发表时间：
2000-05-20
影响因子：
3.8
通讯作者：
Smets, BF
中科院分区：
文献类型：
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作者：
Chandran, K;Smets, BF
硝化作用涉及还原态氮物质如铵态氮（NH4 +-N）到亚硝酸盐态氮（NO2--N）和硝酸盐态氮（NO3--N）的连续生物氧化。在不同的NH4 +-N氧化为NO2--N和NO2--N氧化为NO3--N的相对动力学条件下，考察了将NH4 +-N氧化为NO3--N作为一个复合生化反应模型的适宜性。用选择性抑制剂烯丙基硫脲和叠氮化钠对混合硝化菌群中NH4 +-N氧化为NO2--N和NO2--N氧化为NO3--N进行了解偶联。用快速呼吸计量法测定了NH4 +-N氧化为NO2--N和NO2--N氧化为NO3--N的动力学参数（q（max，ns）和K-s，K-ns）。从电子平衡方程推导出脱氮、吸氧和生物质合成的化学计量系数。NH4 +-N到NO2--N的氧化不受NO2--N浓度高达100 mg NO2--N L-1的影响。NO2--N到NO3--N的氧化被NH4 +-N非竞争性抑制，但NO3--N浓度高达250 mg NO3--N L-1时不受抑制。当NH_4~+-N氧化为NO_2~--N是唯一的限速步骤时，NH_4~+-N氧化为NO_3~--N完全可以看作是一个复合过程。然而，当NH4 +-N到NO2--N的氧化和NO2--N到NO3--N的氧化都是速率限制时，描述NH4 +-N到NO3--N的氧化的估计的集总动力学参数估计是不切实际的高和相关的。这些研究结果表明，使用单步模型来描述批NH4+氧化产生错误的动力学参数时，NH4 +-NO2-氧化不是唯一的限速过程中的整个测定。在这种情况下，需要独立地定量NH4 +-N到NO2--N的氧化和NO2--N到NO3--N的氧化。(C)John Wiley & Sons，Inc. Biotechnol Bioeng 68：396 - 406，2000.
Nitrification involves the sequential biological oxidation of reduced nitrogen species such as ammonium-nitrogen (NH4+-N) to nitrite-nitrogen (NO2--N) and nitrate-nitrogen (NO3--N). The adequacy of modeling NH4+-N to NO3--N oxidation as one composite biochemical reaction was examined at different relative dynamics of NH4+-N to NO2--N and NO2--N to NO3--N oxidation. NH4+-N to NO2--N oxidation and NO2--N to NO3--N oxidation by a mixed nitrifying consortium were uncoupled using selective inhibitors allylthiourea and sodium azide, The kinetic parameters of NH4+-N to NO2--N oxidation (q(max,ns) and K-s,K-ns) and NO2--N to NO3--N oxidation (q(max,nb) and K-s,K-nb) were determined by a rapid extant respirometric technique. The stoichiometric coefficients relating nitrogen removal, oxygen uptake and biomass synthesis were derived from an electron balanced equation. NH4+-N to NO2--N oxidation was not affected by NO2--N concentrations up to 100 mg NO2--N L-1. NO2--N to NO3--N oxidation was noncompetitively inhibited by NH4+-N but was not inhibited by NO3--N concentrations up to 250 mg NO3--N L-1. When NH4+-N to NO2--N oxidation was the sole rate-limiting step, complete NH4+-N to NO3--N oxidation was adequately modeled as one composite process. However, when NH4+-N to NO2--N oxidation and NO2--N to NO3--N oxidation were both rate limiting, the estimated lumped kinetic parameter estimates describing NH4+-N to NO3--N oxidation were unrealistically high and correlated. These findings indicate that the use of single-step models to describe batch NH4+ oxidation yields erroneous kinetic parameters when NH4+-to-NO2- oxidation is not the sole rate-limiting process throughout the assay. Under such circumstances, it is necessary to quantify NH4+-N to NO2--N oxidation and NO2--N to NO3--N oxidation, independently. (C) 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 68: 396-406, 2000.