Nitrous oxide emission potentials of <italic>Burkholderia</italic> species isolated from the leaves of a boreal peat moss <italic>Sphagnum fuscum</italic>*.

Using a culture-based nitrous oxide (N₂O) emission assay, three active N₂O emitters were isolated from <italic>Sphagnum fuscum</italic> leaves and all identified as members of <italic>Burkholderia</italic>. These isolates showed N₂O emission in the medium supplemented with <inline-graphic></inline-graphic> but not with <inline-graphic></inline-graphic>, and <italic>Burkholderia</italic> sp. SF-E2 showed the most efficient N₂O emission (0.20 μg·vial⁻¹·day⁻¹) at 1.0 mM KNO₃. In <italic>Burkholderia</italic> sp. SF-E2, the optimum pH for N₂O production was 5.0, close to that of the phyllosphere of <italic>Sphagnum</italic> mosses, while the optimum temperature was uniquely over 30 °C. The stimulating effect of additional 1.5 mM sucrose on N₂O emission was ignorable, but <italic>Burkholderia</italic> sp<italic>.</italic> SF-E2 upon exposure to 100 mg·L⁻¹<italic>E</italic>-caffeic acid showed uniquely 67-fold higher N₂O emission. All of the three N₂O emitters were negative in both acetylene inhibition assay and PCR assay for <italic>nosZ</italic>-detection, suggesting that N₂O reductase or the gene itself is missing in the N₂O-emitting <italic>Burkholderia</italic>. [ABSTRACT FROM AUTHOR]