Nitrous Oxide Reduction by an Obligate Aerobic Bacterium, <i>Gemmatimonas aurantiaca</i> Strain T-27

다국어 초록 (Multilingual Abstract)

<P>IMPORTANCE Emission of N2O, a potent greenhouse gas and ozone depletion agent, from the soil environment is largely determined by microbial sources and sinks. N2O reduction by organisms with N2O reductases (NosZ) is the only known biological sink of N2O at environmentally relevant concentrations (up to similar to 1,000 parts per million by volume [ppmv]). Although a large fraction of nosZ genes recovered from soil is affiliated with nosZ found in the genomes of the obligate aerobic phylum Gemmatimonadetes, N2O reduction has not yet been confirmed in any of these organisms. This study demonstrates that N2O is reduced by an obligate aerobic bacterium, Gemmatimonas aurantiaca strain T-27, and suggests a novel regulation mechanism for N2O reduction in this organism, which may also be applicable to other obligate aerobic organisms possessing nosZ genes. We expect that these findings will significantly advance the understanding of N2O dynamics in environments with frequent transitions between oxic and anoxic conditions.</P>