NOX2N - Transformation of biogas digestates to a fertilizer which reduce N2O emissions

N2O

N2O emissions account for 1/3 of the total climate forcing of food production. This N2O is generated through successive nitrification then denitrification by soil microbiota, fuelled by elevated nitrogen levels from fertilisers. If global warming is to be limited to 2°C as set in the Paris Agreement, mitigation options for these N2O emissions will need to be developed!

NOX2N Technology

The technology pioneers a novel approach to transform inexpensive biogas digestates into a high-density enrichment of non-denitrifying N2O-reducing bacteria (NNRB), which creates opportunity for scalable and feasible inoculation of agricultural soils with desired bacteria. The use of NOX2N technology to modify the soil microbiome, be it for for reduced climate emissions or increased crop yields, fits well with current claims that microbiome-based innovations will play crucial roles in circular economy approaches to meet the United Nations sustainable development goals.



NOX2N project

The NOX2N project (project partners: Veas WWTP, NMBU and Ard Innovation) is supported by the Norwegian Research Counsil under the programme "Innovation in the public sector" and aims to increase the Technology Readyness Level (TRL) of the technology to 5-6. This by implementing a pilot plant in the existing sludge treatment line at Veas WWTP and by validating the concept in different organic waste substrates. The projects advisory board consist of stakeholders representing government legislators, environmental agencies, producers and end-users.

NOX2N in the media


Forklart – Aftenposten Podkast - To gode klimanyheter - Aftenposten.no

NMBU-forskere fant en bakterie som spiser lystgass - "Det ble en del high-fives" - Nationen.no

Nytt våpen mot global oppvarming: - Et særdeles stort gjennombrudd - Aftenposten.no

    -   Stort gjennombrudd: Kan kutte utslipp fra landbruket med 95 prosent - Nationen.no

    -   Nytt våpen mot global oppvarming: – Et særdeles stort gjennombrudd - BergensTidende.no

    -   Nytt våpen mot glo­bal opp­varming: – Et sær­deles stort gjennom­brudd - Aftenbladet.no

   -   Ny metode kan redusere skadelig lystgassutslipp fra landbruket kraftig Mat og Marked

Ny metode kan redusere lystgassutslipp fra landbruket med 95 prosent - NMBU.no

Alf Bjørseths inspirasjonspris 2022 - NMBU.no

Winner of Alf Bjørseths Inspirational Award - Scatech Innovation

Bakterier som spiser lystgass, skal hjelpe landbruket med klimakutt - Nationen.no

En glad miljøhistorie om kloakk og lystgass - NMBU.no

Bakterier som spiser lystgass, kan kutte klimagassutslipp fra landbruket - Forskning.no

Veas innvolvert i NMBU-forskningsprosjekt om lystgasspisende bakterier - Biogassbransjen.no

Lystige bakterier kan gjøre landbruket mer klimavennlig - VAnytt.no


Publications

4: Meta-omics analyses of dual substrate enrichment culturing of nitrous oxide respiring bacteria suggest that attachment and complex polysaccharide utilisation contributed to the ability of Cloacibacterium strains to reach dominance

Synopsis:
 
The dual substrate enrichment strategy effectively selected operational taxonomic units (OTU’s) which were able to grow (or as a minimum survive) both in soil and digestate. The genetic elements and molecular mechanisms responsible for the success of these phenotypes and which were enriched for during dual enrichment, however, are still to be determined. In this work, we used combined metagenomics and metaproteomics to 1) examine the organisms and genes which were enriched during the dual substrate enrichment with a focus on nitrogen transformation genes 2) investigate what traits benefitted the enrichment winners and 3) examine the proteins/metabolisms used by the enrichment winner during growth in the dual-substrate enrichment.

Vick SHW, Jonassen KR, Arntzen MØ, Lycus P, Bakken LR (2023) Meta-omics analyses of dual substrate enrichment culturing of nitrous oxide respiring bacteria suggest that attachment and complex polysaccharide utilisation contributed to the ability of Cloacibacterium strains to reach dominance, bioRxiv 2023.06.04.543644; doi: https://doi.org/10.1101/2023.06.04.543644

3: A dual enrichment strategy provides soil and digestate competent N2O-respiring bacteria for mitigating climate forcing in agriculture (mBio, Open access)

Synopsis:

An enrichment strategy, based on ecological concepts (Lotka-Voltera competition model), was designed to enrich and isolate generalist NRBs to provide organisms capable of sustaining their activity in both soil- and digestate environments. As predicted by the Lotka-Volterra competition model, cluster analysis identified generalist operational taxonomic units (OTUs) which became dominant, digestate/soil-specialists which did not, and a majority that were gradually diluted out. We isolated several NRBs circumscribed by dominating generalist OTUs. Their denitrification genes and phenotypes predicted a variable capacity to act as N2O-sinks, while all genomes predicted broad catabolic capacity, showing prolonged N2O reducing activity in soil microcosm experiments, thus contrasting previous attempts to enrich NRB by anaerobic incubation of digestate only, which selected for organisms with a catabolic capacity limited to fermentation products.

Jonassen KR, Ormaasen I, Duffner C, Hvidsten TR, Frostegård Å, Bakken LR, Vick SHW (2021b) A dual enrichment strategy provides soil-and digestate-competent N2O-respiring bacteria for mitigating climate forcing in agriculture. mBio, e00788-22. https://doi.org/10.1128/mbio.00788-

2: Nitrous oxide respiring bacteria in biogas digestates for reduced agricultural emissions (The ISME Journal, Open access)

Synopsis:

Here we show that manipulating soil metabolism by heavy inoculation with NRBs is realistic if one can tap in to the organic waste value chain and use the residue from anaerobic digestion (digestate) as substrate and vector for the growth and transferral of NRBs to soil. However, in these first attempts to enrich and isolate suitable digestate competent NRBs in live digestate it became clear that the enriched organisms’ competitive strengths in soil was modest, with only transient effects on soil N2O emissions, likely because the isolated NRBs were metabolically streamlined to utilization of fermentation intermediates produced by the active methanogenic community.

Jonassen KR, Hagen LH, Vick SHW, Arntzen MØ, Eijsink VGA, Frostegård Å, Lycus P, Molstad L, Pope PB, Bakken LR (2021) Nitrous oxide respiring bacteria in biogas digestates for reduced agricultural emissions. The ISME Journal, 1-11. https://doi.org/10.1038/s41396-021-01101-x

1: Biogas digestate as substrate and vector for the intorduction of N2O-respiring bacteria to soil (phd-thesis)

Jonassen KR (2021) Biogas digestate as substrate and vector for the introduction of N2O-respiring bacteria to soil (doctoral thesis), Available from: Brage NMBU Thesis 2021:53 ISBN: 978-82-575-1824-0, Norwegian University of Life Sciences.


Coming publications (tentative title)

5: Testing NRB enriched digestate in field scale - significant N2O reductions!

Synopsis:

Upscaling the NRB-technology in soil bucket trials and larger field scale trials; fertilizing various agricultural soils with NRB-enriched digestate efficiently reduces N2O emissions by 40 - 95 % depending on soil type.