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bioRxiv · 10.1101/2023.10.19.563143

Effective biotechnology for reducing N2O-emissions from farmland: N2O-respiring bacteria vectored by organic waste

Hiis, E. G.·Vick, S. H. W.·Molstad, L.·Rosdal, K.·Jonassen, K. R.·Winiwarter, W.·Bakken, L. R.
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Abstract

Farmed soils contribute to global warming primarily by N2O-emissions, and mitigation has proven difficult. However, a novel approach with promising results in the laboratory, exploits organic wastes both as substrates and vectors for strains of N2O-respiring bacteria (NRB), selected for their ability to survive in soil. Here we demonstrate a strong effect in field experiments: fertilization with waste from biogas-production, in which the strain Cloacibacterium sp. CB-01 had grown aerobically to [~]6*109 cells mL-1, reduced N2 O-emissions by 50-95 %. The strong and long-lasting effect of CB-01 is ascribed to its tenacity in soil, rather than its biokinetic parameters, which were inferior to other NRB-strains. Scaling up to EU level, we find that national anthropogenic N2O-emissions can be reduced by 5-20 %, and more if including other organic wastes. This opens an avenue for cost-effective reduction of N2O-emissions for which other mitigation options are currently lacking.

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Hiis, E. G., Vick, S. H. W., Molstad, L., Rosdal, K., Jonassen, K. R., Winiwarter, W., Bakken, L. R.. 2023-10-19. Effective biotechnology for reducing N2O-emissions from farmland: N2O-respiring bacteria vectored by organic waste. https://doi.org/10.1101/2023.10.19.563143

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