Bowmanella denitrificans gen. nov., sp nov., a denitrifying bacterium isolated from seawater from An-Ping Harbour, Taiwan

A heterotrophic, non-fermentative, denitrifying isolate, designated strain BD1(T), was obtained from a seawater sample collected in the shallow coastal region of An-Ping Harbour, Tainan, Taiwan. The cells of strain BD1(T) were Gram-negative. Cells grown in broth cultures were curved rods that were motile by means of a single polar flagellum. Growth occurred between 10 and 40 degrees C, with an optimum at 30-35 degrees C. Strain BD1(T) grew in NaCl levels of 0-10%, with better growth occurring at 1-3%. It grew aerobically and could achieve anaerobic growth by adopting a denitrifying metabolism with nitrate or nitrous oxide as the terminal electron acceptor. The major fatty acids were C-16:0, C-18:1 omega 7c and summed feature 3 (C-16:1 omega 7c and/or C-15:0 iso 2-OH). The polar lipids consisted of phosphatidylethanolamine (56.6%) and phosphatidylglycerol (43.4%). The isoprenoid quinones were Q-8 (81.5%), Q-9 (11.1%) and Q-10 (7.4%). The DNA G + C content was 50.0 mol%. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain BD1(T) formed a distinct lineage in the Gammaproteobacteria and that it exhibited the highest level of sequence similarity with species of the genera Alteromonas (92.8-93.7%), Aestuariibacter (93.0%), Glaciecola (90.4-92.7%)and Salinimonas (91.8%). Strain BD1(T) was distinguishable from species of these genera by the presence of Q-9 and Q-10. Phenotypically, strain BD1(T) was also distinguishable from species of these genera in that it did not require NaCl for growth and was capable of denitrification. On the basis of the polyphasic data from this study, the isolate represents a novel species within a novel genus, for which the name Bowmanella denitrificans gen. nov., sp. nov. is proposed. The type strain of Bowmanella denitrificans is BD1(T) (= BCRC 17491(T) = JCM 13378(T)).