Identification of a denitrifying gliding bacterium, isolated from soil and able to reduce nitrous oxide in the presence of sulfide and acetylene, as Flexibacter canadensis.

We have reexamined the properties of a gliding bacterium, Is-11, which was previously isolated from soil because of its ability to denitrify and to reduce nitrous oxide in the presence of sulfide and normally inhibitory concentrations of acetylene. Occurrence of such an organism may have important implications for the use of the acetylene inhibition assay for measuring denitrification rates in reduced, sulfidic environments. Although originally tentatively identified as a Cytophaga sp., extensive morphological, physiological, and biochemical tests as well as G+C analysis and DNA hybridization studies now indicate that the soil isolate Is-11 is a strain of Flexibacter canadensis. Key words: gliding bacteria, Flexibacter canadensis, denitrification, acetylene, sulfide, nitrous oxide.