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.

自长期以来，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。它们中的大多数与硝化的第二步有关，并关注亚硝酸盐氧化细菌（NOB）。 i）与有关两个不同微生物行会的教科书知识相反，检测到氨（Comammox）的氨（Comammox）的完全氧化，由著名的硝基螺旋体进行。 ii）在欧洲的某些WWTP中，中度气候的一些WWTP，冷适应的硝化核酸和不是硝基螺旋体似乎是最丰富的亚硝酸盐氧化细菌。 iii）硝基素是氯曲线叶绿素的第一个硝酸盐，是废水中亚硝酸盐氧化的新候选者。因此，很明显，仍然可以发现具有未知生理特征的新氨和亚硝酸盐氧化微生物。我们的发现验证了环境变量根据利基分离而决定的，反之亦然，新颖的NOB可以通过竞争条件通过定向的培养方法来获得。在该项目的第一部分中，我们成功地富集了硝基螺旋藻和硝基核的新型新型物种，以扩展表型和基因组研究的参考生物集。比较选定的生理特征，以了解塑造NOB多样性的驱动力。例如，在42°C的升高温度（同时减少的氧气含量下）的孵育对于从活化污泥中获得的新硝基螺旋体的增殖至关重要。除了温度和底物浓度外，我们现在可以证明，与冷淡水水产养殖厂的生物滤器相比，与硝基核心相比，略带酸性的pH值对于上调硝基果会很重要。在动力学实验中，分析了属于五个属的13种NOB物种的底物亲和力，并表明硝基核心和硝基核的亚硝酸盐的KM值明显低于硝酸杆菌的氮气值，否则表明最大最大活性Vmax。 QPCR揭示的，生物反应器中的首次竞争实验可以证实在低温（17°C）下硝基核与硝基螺旋体的优势。然而，与氮的样品起源相关的两个混合NOB之一的优势显然受pH（6.5 vs 7.4）的影响。在下一个项目阶段，将使用其他硝基螺旋体和硝基核种类对这种复杂的调节进行更详细的分析。除了修改矿物培养基和孵化条件外，我们还将重点关注与异嗜性养殖的共同培养，在此，辅助细菌的帮助可能会占据挑剔的NOB的增殖。此外，新型NOB基因发育的培养与叶绿素（硝基氮的亲戚）的培养将扩大我们对该功能性公会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