Eawag - Swiss Federal Institute of Aquatic Science and Technology

Die autotrophe Beseitigung von Stickstoff (N) durch anaerobe Ammoniumoxidation (Anammox) ist ein wichtiger Mechanismus der N-Eliminierung, sowohl in technischen als auch in natürlichen Systemen. Im Hauptstrom von Kläranlagen könnte es sogar den Betrieb unter Energieautarkie ermöglichen. Die autotrophe N-Entfernung durch Anammox-Bakterien umfasst die gleichzeitige Oxidation von Ammonium (NH₄ +) und Reduktion von Nitrit (NO₂-) unter sauerstoffarmen Bedingungen in einer Reaktion, die zuerst in einer de-nitrifizierenden Kläranlage entdeckt wurde. Das metabolische Endprodukt vom Anammoxprozess ist gelöstes N₂, was es zu einem effizienten fixierten N-Eliminierungsweg in technischen Systemen macht.

Das Ziel des multidisziplinären IsoMol Projektes ist es, die Zusammenhänge zwischen biochemischen Stoffwechselwegen, der Leistung mikrobieller Gemeinschaften, Umweltbedingungen und der mikrobiellen Zusammensetzung in der autotrophen Stickstoffeliminierung zu verstehen.
In diesem Projekt wird das Department für mikrobielle Ökologie der Eawag Kastanienbaum die Aktivität und ökologische Stabilität von Anammox-Biofilmen untersuchen. Ein besseres Verständnis über die Aktivitäten von Anammox-Konsortien ist entscheidend für die Aufrechterhaltung der Prozessstabilität und damit für die Verwendbarkeit der autotrophen N-Entfernung in größerem Maßstab. Widerstand (Grad, in dem eine Gemeinschaft Veränderungen im Angesicht von Störungen widersteht) und Resilienz (Fähigkeit der Gemeinschaft, in den Zustand vor der Störung zurückzukehren) sind zwei quantifizierbare Metriken, die die mikrobielle Gemeinschaftsstabilität direkt beeinflussen. Unser Hauptziel ist es nun, die Schlüsselmechanismen, welche Resistenz und Resilienz von mikrobiellen Gemeinschaften zugrunde liegen zu identifizieren und zu verstehen.
Wir werden Stressexperimente in kleinmaßstäbigen Bioreaktoren an der Eawag Dübendorf durchführen. Durch die Kombination von Leistungsparametern, Biodiversitätsindizes und Gentranskripten wird es uns dann möglich sein Stabilitätsgrenzbereiche abzuschätzen. Die Ergebnisse aus den Experimenten werden uns helfen, die mechanistischen Grundlagen von Stabilität und Kollaps in komplexen Anammox-Biofilmen zu verstehen.

Dr. Helmut Bürgmann Gruppenleiter Mikrobielle Öklologie Tel. +41 58 765 2165 Inviare e-mail

Dr. Robert Niederdorfer Tel. +41 58 765 2215 Inviare e-mail

Isomol: Sinergia Project (SNSF)

Adriano Joss, Eawag

Moritz F. Lehmann, Universität Basel

Joachim Mohn, EMPA

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   0 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=22551, pid=124)
      originalId => protected22551 (integer)
      authors => protected'Niederdorfer,&nbsp;R.; Fragner,&nbsp;L.; Yuan,&nbsp;L.; Hausherr,&nbsp;D.; W
         ei,&nbsp;J.; Magyar,&nbsp;P.; Joss,&nbsp;A.; Lehmann,&nbsp;M.&nbsp;F.; Ju,&n
         bsp;F.; Bürgmann,&nbsp;H.' (178 chars)
      title => protected'Distinct growth stages controlled by the interplay of deterministic and stoc
         hastic processes in functional anammox biofilms' (123 chars)
      journal => protected'Water Research' (14 chars)
      year => protected2021 (integer)
      volume => protected200 (integer)
      issue => protected'' (0 chars)
      startpage => protected'117225 (14 pp.)' (15 chars)
      otherpage => protected'' (0 chars)
      categories => protected'mainstream anammox; biofilm succession; FISH; amplicon sequencing; sequencin
         g; batch reactor; biofilm structure' (111 chars)
      description => protected'Mainstream anaerobic ammonium oxidation (anammox) represents one of the most
          promising energy-efficient mechanisms of fixed nitrogen elimination from wa
         stewaters. However, little is known about the exact processes and drivers of
          microbial community assembly within the complex microbial biofilms that sup
         port anammox in engineered ecosystems. Here, we followed anammox biofilm dev
         elopment on fresh carriers in an established 8m<sup>3</sup> mainstream anamm
         ox reactor that is exposed to seasonal temperature changes (∼25-12°C) and
          varying NH<sub>4</sub><sup>+</sup> concentrations (5-25 mg/L). We use fluor
         escence in situ hybridization and 16S rRNA gene sequencing to show that thre
         e distinct stages of biofilm development emerge naturally from microbial com
         munity composition and biofilm structure. Neutral modelling and network anal
         ysis are employed to elucidate the relative importance of stochastic versus 
         deterministic processes and synergistic and antagonistic interactions in the
          biofilms during their development. We find that the different phases are ch
         aracterized by a dynamic succession and an interplay of both stochastic and 
         deterministic processes. The observed growth stages (<em>Colonization, Succe
         ssion and Maturation</em>) appear to be the prerequisite for the anticipated
          growth of anammox bacteria and for reaching a biofilm community structure t
         hat supports the desired metabolic and functional capacities observed for bi
         ofilm carriers already present in the system (∼100g<sub>NH4-N</sub> m<sup>
         3</sup> d<sup>-1</sup>). We discuss the relevance of this improved understan
         ding of anammox-community ecology and biofilm development in the context of 
         its practical application in the start-up, configuration, and optimization o
         f anammox biofilm reactors.' (1775 chars)
      serialnumber => protected'0043-1354' (9 chars)
      doi => protected'10.1016/j.watres.2021.117225' (28 chars)
      uid => protected22551 (integer)
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   1 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=22399, pid=124)
      originalId => protected22399 (integer)
      authors => protected'Gruber,&nbsp;W.; Niederdorfer,&nbsp;R.; Ringwald,&nbsp;J.; Morgenroth,&nbsp;
         E.; Bürgmann,&nbsp;H.; Joss,&nbsp;A.' (113 chars)
      title => protected'Linking seasonal N<sub>2</sub>O emissions and nitrification failures to micr
         obial dynamics in a SBR wastewater treatment plant' (126 chars)
      journal => protected'Water Research X' (16 chars)
      year => protected2021 (integer)
      volume => protected11 (integer)
      issue => protected'' (0 chars)
      startpage => protected'100098 (13 pp.)' (15 chars)
      otherpage => protected'' (0 chars)
      categories => protected'nitrification; denitrification; activated sludge microbiome; physico-chemica
         l monitoring; amplicon sequencing' (109 chars)
      description => protected'Nitrous oxide (N<sub>2</sub>O) is a strong greenhouse gas and causal for str
         atospheric ozone depletion. During biological nitrogen removal in wastewater
          treatment plants (WWTP), high N<sub>2</sub>O fluxes to the atmosphere can o
         ccur, typically exhibiting a seasonal emission pattern. Attempts to explain 
         the peak emission phases in winter and spring using physico-chemical process
          data from WWTP were so far unsuccessful and new approaches are required. Th
         e complex and diverse microbial community of activated sludge used in biolog
         ical treatment systems also exhibit substantial seasonal patterns. However, 
         a potentially causal link between the seasonal patterns of microbial diversi
         ty and N<sub>2</sub>O emissions has not yet been investigated. Here we show 
         that in a full-scale WWTP nitrification failure and N<sub>2</sub>O peak emis
         sions, bad settleability of the activated sludge and a turbid effluent stron
         gly correlate with a significant reduction in the microbial community divers
         ity and shifts in community composition. During episodes of impaired perform
         ance, we observed a significant reduction in abundance for filamentous and n
         itrite oxidizing bacteria in all affected reactors. In some reactors that di
         d not exhibit nitrification and settling failures, we observed a stable micr
         obial community and no drastic loss of species. Standard engineering approac
         hes to stabilize nitrification, such as increasing the aerobic sludge age an
         d oxygen availability failed to improve the plant performance on this partic
         ular WWTP and replacing the activated sludge was the only measure applied by
          the operators to recover treatment performance in affected reactors. Our re
         sults demonstrate that disturbances of the sludge microbiome affect key stru
         ctural and functional microbial groups, which lead to seasonal N<sub>2</sub>
         O emission patterns. To reduce N<sub>2</sub>O emissions from WWTP, it is the
         refore crucial to understand the drivers that lead to the microbial populati
         on dynamics in the activ...' (2012 chars)
      serialnumber => protected'2589-9147' (9 chars)
      doi => protected'10.1016/j.wroa.2021.100098' (26 chars)
      uid => protected22399 (integer)
      _localizedUid => protected22399 (integer)modified
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      _versionedUid => protected22399 (integer)modified
      pid => protected124 (integer)
   2 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=22407, pid=124)
      originalId => protected22407 (integer)
      authors => protected'Magyar,&nbsp;P.&nbsp;M.; Hausherr,&nbsp;D.; Niederdorfer,&nbsp;R.; Stöcklin
         ,&nbsp;N.; Wei,&nbsp;J.; Mohn,&nbsp;J.; Bürgmann,&nbsp;H.; Joss,&nbsp;A.; L
         ehmann,&nbsp;M.&nbsp;F.' (175 chars)
      title => protected'Nitrogen isotope effects can be used to diagnose N transformations in wastew
         ater anammox systems' (96 chars)
      journal => protected'Scientific Reports' (18 chars)
      year => protected2021 (integer)
      volume => protected11 (integer)
      issue => protected'1' (1 chars)
      startpage => protected'7850 (12 pp.)' (13 chars)
      otherpage => protected'' (0 chars)
      categories => protected'' (0 chars)
      description => protected'Anaerobic ammonium oxidation (anammox) plays an important role in aquatic sy
         stems as a sink of bioavailable nitrogen (N), and in engineered processes by
          removing ammonium from wastewater. The isotope effects anammox imparts in t
         he N isotope signatures (<sup>15</sup>N/<sup>14</sup>N) of ammonium, nitrite
         , and nitrate can be used to estimate its role in environmental settings, to
          describe physiological and ecological variations in the anammox process, an
         d possibly to optimize anammox-based wastewater treatment. We measured the s
         table N-isotope composition of ammonium, nitrite, and nitrate in wastewater 
         cultivations of anammox bacteria. We find that the N isotope enrichment fact
         or <sup>15</sup>ε for the reduction of nitrite to N<sub>2</sub> is consiste
         nt across all experimental conditions (13.5‰ ± 3.7‰), suggesting it
          reflects the composition of the anammox bacteria community. Values of <sup>
         15</sup>ε for the oxidation of nitrite to nitrate (inverse isotope effect, 
         - 16 to - 43‰) and for the reduction of ammonium to N<sub>2</sub> (nor
         mal isotope effect, 19-32‰) are more variable, and likely controlled by ex
         perimental conditions. We argue that the variations in the isotope effects c
         an be tied to the metabolism and physiology of anammox bacteria, and that th
         e broad range of isotope effects observed for anammox introduces complicatio
         ns for analyzing N-isotope mass balances in natural systems.' (1428 chars)
      serialnumber => protected'2045-2322' (9 chars)
      doi => protected'10.1038/s41598-021-87184-0' (26 chars)
      uid => protected22407 (integer)
      _localizedUid => protected22407 (integer)modified
      _languageUid => protectedNULL
      _versionedUid => protected22407 (integer)modified
      pid => protected124 (integer)
   3 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=22013, pid=124)
      originalId => protected22013 (integer)
      authors => protected'Niederdorfer,&nbsp;R.; Hausherr,&nbsp;D.; Palomo,&nbsp;A.; Wei,&nbsp;J.; Mag
         yar,&nbsp;P.; Smets,&nbsp;B.&nbsp;F.; Joss,&nbsp;A.; Bürgmann,&nbsp;H.' (147 chars)
      title => protected'Temperature modulates stress response in mainstream anammox reactors' (68 chars)
      journal => protected'Communications Biology' (22 chars)
      year => protected2021 (integer)
      volume => protected4 (integer)
      issue => protected'1' (1 chars)
      startpage => protected'23 (12 pp.)' (11 chars)
      otherpage => protected'' (0 chars)
      categories => protected'' (0 chars)
      description => protected'Autotrophic nitrogen removal by anaerobic ammonium oxidizing (anammox) bacte
         ria is an energy-efficient nitrogen removal process in wastewater treatment.
          However, full-scale deployment under mainstream conditions remains challeng
         ing for practitioners due to the high stress susceptibility of anammox bacte
         ria towards fluctuations in dissolved oxygen (DO) and temperature. Here, we 
         investigated the response of microbial biofilms with verified anammox activi
         ty to DO shocks under 20 °C and 14 °C. While pulse disturbances of 0.3 mg 
         L<sup>−1</sup> DO prompted only moderate declines in the NH<sub>4</sub><su
         p>+</sup> removal rates, 1.0 mg L<sup>−1</sup> DO led to complete but reve
         rsible inhibition of the NH<sub>4</sub><sup>+</sup> removal activity in all 
         reactors. Genome-centric metagenomics and metatranscriptomics were used to i
         nvestigate the stress response on various biological levels. We show that te
         mperature regime and strength of DO perturbations induced divergent response
         s from the process level down to the transcriptional profile of individual t
         axa. Community-wide gene expression differed significantly depending on the 
         temperature regime in all reactors, and we found a noticeable impact of DO d
         isturbances on genes involved in transcription, translation, replication and
          posttranslational modification at 20 °C but not 14 °C. Genome-centric ana
         lysis revealed that different anammox species and other key biofilm taxa dif
         fered in their transcriptional responses to distinct temperature regimes and
          DO disturbances.' (1537 chars)
      serialnumber => protected'2399-3642' (9 chars)
      doi => protected'10.1038/s42003-020-01534-8' (26 chars)
      uid => protected22013 (integer)
      _localizedUid => protected22013 (integer)modified
      _languageUid => protectedNULL
      _versionedUid => protected22013 (integer)modified
      pid => protected124 (integer)

Niederdorfer, R.; Fragner, L.; Yuan, L.; Hausherr, D.; Wei, J.; Magyar, P.; Joss, A.; Lehmann, M. F.; Ju, F.; Bürgmann, H. (2021) Distinct growth stages controlled by the interplay of deterministic and stochastic processes in functional anammox biofilms, Water Research, 200, 117225 (14 pp.), doi:10.1016/j.watres.2021.117225, Institutional Repository

Gruber, W.; Niederdorfer, R.; Ringwald, J.; Morgenroth, E.; Bürgmann, H.; Joss, A. (2021) Linking seasonal N₂O emissions and nitrification failures to microbial dynamics in a SBR wastewater treatment plant, Water Research X, 11, 100098 (13 pp.), doi:10.1016/j.wroa.2021.100098, Institutional Repository

Magyar, P. M.; Hausherr, D.; Niederdorfer, R.; Stöcklin, N.; Wei, J.; Mohn, J.; Bürgmann, H.; Joss, A.; Lehmann, M. F. (2021) Nitrogen isotope effects can be used to diagnose N transformations in wastewater anammox systems, Scientific Reports, 11(1), 7850 (12 pp.), doi:10.1038/s41598-021-87184-0, Institutional Repository

Niederdorfer, R.; Hausherr, D.; Palomo, A.; Wei, J.; Magyar, P.; Smets, B. F.; Joss, A.; Bürgmann, H. (2021) Temperature modulates stress response in mainstream anammox reactors, Communications Biology, 4(1), 23 (12 pp.), doi:10.1038/s42003-020-01534-8, Institutional Repository

Abteilung Oberflächengewässer

Ökologische Stabilität von mikrobiellen Gemeinschaften in gemischten Nitritation-Anammox (Subprojekt von IsoMol)