Sustained bacterial N<sub>2</sub>O reduction at acidic pH.

He, Guang; Chen, Gao; Xie, Yongchao; Swift, Cynthia M; Ramirez, Diana; Cha, Gyuhyon; Konstantinidis, Konstantinos T; Radosevich, Mark et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Nitrous oxide (N<sub>2</sub>O) is a climate-active gas with emissions predicted to increase due to agricultural intensification. Microbial reduction of N<sub>2</sub>O to dinitrogen (N<sub>2</sub>) is the major consumption process but microbial N<sub>2</sub>O reduction under acidic conditions is considered negligible, albeit strongly acidic soils harbor nosZ genes encoding N<sub>2</sub>O reductase. Here, we study a co-culture derived from acidic tropical forest soil that reduces N<sub>2</sub>O at pH 4.5. The co-culture exhibits bimodal growth with a Serratia sp. fermenting pyruvate followed by hydrogenotrophic N<sub>2</sub>O reduction by a Desulfosporosinus sp. Integrated omics and physiological characterization revealed interspecies nutritional interactions, with the pyruvate fermenting Serratia sp. supplying amino acids as essential growth factors to the N<sub>2</sub>O-reducing Desulfosporosinus sp. Thus, we demonstrate growth-linked N<sub>2</sub>O reduction between pH 4.5 and 6, highlighting microbial N<sub>2</sub>O reduction potential in acidic soils.

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