A renewed view on the complex community of nitrite oxidizing bacteria derived from sewage

对污水中亚硝酸盐氧化细菌复杂群落的新认识

基本信息

批准号：
230977559
负责人：
Privatdozentin Dr. Eva Spieck
金额：
--
依托单位：
Abteilung für Mikrobiologie und Biotechnologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/230977559?language=en
关键词：
renewed view complex community nitrite

项目摘要

It has been known since a long time that nitrification is a key process of biological wastewater treatment, but still surprising features have been discovered very recently. Most of them are related to the second step of nitrification and concern nitrite oxidizing bacteria (NOB). I) In contrast to textbook knowledge about two distinct microbial guilds, complete oxidation of ammonia to nitrate (comammox) was detected, performed by the well-known Nitrospira. II) In some WWTPs in Europe of moderate climate, the cold-adapted Nitrotoga and not Nitrospira seems to be the most abundant nitrite oxidizing bacterium. III) Nitrolancea, the first nitrifier belonging to the phylum Chloroflexi, is a new candidate for nitrite oxidation in wastewaters. Therefore, it became obvious that still novel ammonia and nitrite oxidizing microorganisms with unknown physiological features can be discovered.Our findings verify that environmental variables decide in terms of niche separation and vice versa, novel NOB can be obtained by a directed cultivation approach using competitive conditions. In the first part of the project, we successfully enriched and partly isolated novel species of Nitrospira and Nitrotoga to extend the set of reference organisms for phenotypic and genomic investigations. Selected physiological characteristics were compared in order to understand the driving forces for shaping diversity of NOB. For example, incubation at elevated temperature of 42°C (and simultaneously at reduced oxygen content) was critical for proliferation of a new species of Nitrospira obtained from activated sludge. Apart from temperature and substrate concentration, we now could demonstrate that a slightly acidic pH-value is of importance for upregulation of Nitrotoga in comparison to Nitrospira in a biofilter of a cold freshwater aquaculture plant. In kinetic experiments, the substrate affinity was analyzed for 13 species of NOB belonging to five genera and it was shown that the Km value for nitrite of Nitrospira and Nitrotoga is clearly lower than that of Nitrobacter, which otherwise revealed the highest maximum activity Vmax. First competition experiments in bioreactors could confirm the advantage of Nitrotoga versus Nitrospira at low temperature (17°C), as revealed by qPCR. However, the dominance of one of two mixed NOB was clearly influenced by pH (6.5 vs 7.4) in correlation with the sample origin of Nitrotoga. Such complex regulation will be analyzed in more detail with further species of Nitrospira and Nitrotoga in the next project phase. Besides modification of mineral media and incubation conditions, we will also focus on co-cultures with heterotrophs, where the assistance of helper bacteria might facilitate proliferation of fastidious NOB. Moreover, cultivation of novel NOB phylogenetically affiliated to the Chloroflexi (relatives of Nitrolancea hollandica) will broaden our knowledge about specific growth preferences of this functional guild.

人们很早就知道硝化是生物废水处理的关键过程，但最近仍然发现了令人惊讶的特征，其中大多数与硝化的第二步有关，并涉及亚硝酸盐氧化细菌（NOB I）。）与教科书上有关两个不同微生物群的知识相反，在一些微生物中，检测到氨完全氧化成硝酸盐（comammox），这是由著名的 Nitrospira II）完成的。在气候温和的欧洲污水处理厂中，适应寒冷的 Nitrotoga 而不是 Nitrospira 似乎是最丰富的亚硝酸盐氧化细菌 III) Nitrolancea，属于 Chloroflexi 门的第一个硝化细菌，是废水中亚硝酸盐氧化的新候选细菌。很明显，仍然可以发现具有未知生理特征的新型氨和亚硝酸盐氧化微生物。我们研究结果证实，环境变量决定了生态位分离，反之亦然，可以通过使用竞争条件的定向培养方法获得新的 NOB。在该项目的第一部分，我们成功地富集并部分分离了 Nitrospira 和 Nitrotoga 的新物种。扩展了用于表型和基因组研究的参考生物组，以了解形成 NOB 多样性的驱动力。批判的对于从活性污泥中获得的新 Nitrospira 物种的增殖，除了温度和底物浓度之外，我们现在可以证明，与冷淡水水产养殖生物过滤器中的 Nitrospira 相比，微酸性 pH 值对于 Nitrotoga 的上调非常重要。在动力学实验中，对5属13种NOB进行了底物亲和力分析，结果表明，Nitrospira和Nitrotoga对亚硝酸盐的Km值为：明显低于硝化细菌，否则显示了最高的最大活性 Vmax。在生物反应器中的首次竞争实验可以证实 Nitrotoga 相对于 Nitrospira 在低温（17°C）下的优势，如 qPCR 所示。两种混合 NOB 明显受到与 Nitrotoga 样品来源相关的 pH 值（6.5 与 7.4）的影响，这种复杂的调节将通过 Nitrospira 和其他物种进行更详细的分析。 Nitrotoga 在下一阶段的项目中，除了修改矿物培养基和培养条件外，我们还将重点关注与异养生物的共培养，其中辅助细菌的协助可能会促进挑剔的 NOB 的增殖，此外，培养属于系统发育的新型 NOB。 Chloroflexi（Nitrolancea hollandica 的亲戚）将拓宽我们对这个功能性行会的特定生长偏好的了解。

项目成果

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Low Temperature and Neutral pH Define “Candidatus Nitrotoga sp.” as a Competitive Nitrite Oxidizer in Coculture with Nitrospira defluvii

DOI：
10.1128/aem.02569-18
发表时间：
2019-03
期刊：
Applied and Environmental Microbiology
影响因子：
4.4
作者：
S. Wegen;Boris Nowka;E. Spieck
通讯作者：
S. Wegen;Boris Nowka;E. Spieck

Expanded metabolic versatility of ubiquitous nitrite-oxidizing bacteria from the genus Nitrospira

DOI：
10.1073/pnas.1506533112
发表时间：
2015-09-08
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
影响因子：
11.1
作者：
Koch, Hanna;Luecker, Sebastian;Daims, Holger
通讯作者：
Daims, Holger

Comparison of Oxidation Kinetics of Nitrite-Oxidizing Bacteria: Nitrite Availability as a Key Factor in Niche Differentiation