A novel bacterial strain, S-12T, of a member of the genus Phreatobacterwas isolated from a cathode of a microbial fuel cell from Suwon City, South Korea. Cells were Gram-staining-negative, aerobic, non-sporulating rods, motile by means of a polar flagellum, and formed white round colonies. The strain grew at the range of 10-40 °C (optimum, 28-30 °C), pH 6.0-10.0 (optimum 7.0-8.0) and 0-1 % NaCl. The 16S rRNA gene sequence analysis showed the relatedness of S-12T to Phreatobacter stygiusYC6-17T (98.2 %) and Phreatobacter oligotrophusPI_21T (98.1 %). The major respiratory quinone was ubiquinone Q-10. Polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and an unidentified lipid. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The DNA G+C content was 69.3 mol%. On the basis of its differences from species of the genus Phreatobacter with validly published names, strain S-12T is identified as representing a novel species, for which the proposed name is Phreatobactercathodiphilus sp. nov., with S-12T as the type strain (=KACC 18497T=JCM 31612T).
Keywords: Phreatobacter cathodiphilus; new taxa; plant microbial fuel cell; taxonomy.