Comparison of Oxidation Kinetics of Nitrite-Oxidizing Bacteria: Nitrite Availability as a Key Factor in Niche Differentiation
Comparison of Oxidation Kinetics of Nitrite-Oxidizing Bacteria: Nitrite Availability as a Key Factor in Niche Differentiation
复制标题
DOI：
10.1128/aem.02734-14
复制
发表时间：
2015-01-01
影响因子：
4.4
通讯作者：
Spieck, Eva
中科院分区：
文献类型：
--
作者：
Nowka, Boris;Daims, Holger;Spieck, Eva
硝化作用对自然生态系统和污水处理厂中的氮循环有着巨大的影响。数学模型作为工具来捕捉这些生物系统的复杂性，但动力学参数，特别是亚硝酸盐氧化细菌（NOB）的缺乏，因为数量有限的纯培养物，直到最近。在这项研究中，我们比较了六个纯培养物和一个富集培养物代表三个属的NOB（硝化杆菌，硝化螺菌，Nitrotoga）的亚硝酸盐氧化动力学。与半饱和常数（Km）之间的9和27 μ M的亚硝酸盐，硝化螺菌适应生活在显着的底物限制。硝化细菌表现出广泛的低底物亲和力，与K-M值之间的49和544亩M亚硝酸盐。然而，在过量的亚硝酸盐供应下，硝化细菌的优势显现出来，维持64至164 μ mol亚硝酸盐/mg蛋白/h的高最大比活性（V-max），与硝化螺菌的18至48 μ mol亚硝酸盐/mg蛋白/h的较低活性相反。在17摄氏度的低温下测得的“北极硝托加”的V-max（26 μ mol亚硝酸盐/mg蛋白/h）和K-m（58 μ M亚硝酸盐）表明，特别是在寒冷的生境中，硝托加可以有利地与其他NOB竞争。确定的动力学参数代表硝化模型的改进的基础值，并将支持在自然和工程生态系统的群落结构和硝化速率的预测。
Nitrification has an immense impact on nitrogen cycling in natural ecosystems and in wastewater treatment plants. Mathematical models function as tools to capture the complexity of these biological systems, but kinetic parameters especially of nitrite-oxidizing bacteria (NOB) are lacking because of a limited number of pure cultures until recently. In this study, we compared the nitrite oxidation kinetics of six pure cultures and one enrichment culture representing three genera of NOB (Nitrobacter, Nitrospira, Nitrotoga). With half-saturation constants (K-m) between 9 and 27 mu M nitrite, Nitrospira bacteria are adapted to live under significant substrate limitation. Nitrobacter showed a wide range of lower substrate affinities, with K-m values between 49 and 544 mu M nitrite. However, the advantage of Nitrobacter emerged under excess nitrite supply, sustaining high maximum specific activities (V-max) of 64 to 164 mu mol nitrite/mg protein/h, contrary to the lower activities of Nitrospira of 18 to 48 mu mol nitrite/mg protein/h. The V-max (26 mu mol nitrite/mg protein/h) and K-m (58 mu M nitrite) of "Candidatus Nitrotoga arctica" measured at a low temperature of 17 degrees C suggest that Nitrotoga can advantageously compete with other NOB, especially in cold habitats. The kinetic parameters determined represent improved basis values for nitrifying models and will support predictions of community structure and nitrification rates in natural and engineered ecosystems.