Nitratireductor pacificus sp nov., isolated from a pyrene-degrading consortium

Strain pht-3B(T) was isolated from a pyrene-degrading consortium of an enriched sediment from the Pacific Ocean, collected during the screening of polycyclic aromatic hydrocarbon-degrading bacteria. Cells were Gram-negative, short rods that were motile by means of flagella. Growth was observed at 0-7% NaCl and 10-41 C. The isolate was able to reduce nitrate to nitrite, but not to nitrogen. 16S rRNA gene sequence comparisons showed that strain pht-3B(T) was most closely related to Nitratireductor aquibiodomus NL21(T) (97.3% 16S rRNA gene sequence similarity), N. indicus C115(T) (97.1 %), N. basaltis J3(T) (96.8 %) and N. kimnyeongensis KY 101(T) (96.7%). DNA-DNA hybridization between strain pht-3B(T) and these reference strains revealed 55, 54, 28 and 42% DNA-DNA relatedness, respectively. The dominant fatty acids were C-19:0 omega 8c cyclo (22.6%) and summed feature 8 (consisting of C-18:1 omega 7c and/or C-18:1 omega 6c; 60.4%). The G+C content of the chromosomal DNA was 63 molok. These characteristics were in good agreement with those of members of the genus Nitratireductor. According to cell morphology, physiology, fatty acid composition, 16S rRNA gene sequence analysis and DNA-DNA relatedness, the isolate belonged to the genus Nitratireductor but could be readily distinguished from recognized species of the genus. Therefore a novel species is proposed to accommodate strain pht-3B(T), for which the name Nitratireductor pacificus sp. nov. is proposed. The type strain is pht-3B(T) (=CCTCC AB 209302(T)=LMG 25541(T)=MCCC 1A01024(T)).