Vibrio nitrifigilis sp. nov., a marine nitrogen-fixing bacterium isolated from the lagoon sediment of an islet inside an atoll

A nitrogen-fixing isolate of facultatively anaerobic, marine bacterium, designated strain NFV-1 T , was recovered from the lagoon sediment of Dongsha Island, Taiwan. It was a Gram-negative rod which exhibited motility with monotrichous flagellation in broth cultures. The strain required NaCl for growth and grew optimally at about 25–35 °C, 3% NaCl and pH 7–8. It grew aerobically and could achieve anaerobic growth by fermenting d -glucose or other carbohydrates as substrates. NH 4 Cl could serve as a sole nitrogen source for growth aerobically and anaerobically, whereas growth with N 2 as the sole nitrogen source was observed only under anaerobic conditions. Cellular fatty acids were predominated by C 16:1 ω 7 c , C 16:0 , and C 18:1 ω 7 c . The major polar lipids consisted of phosphatidylethanolamine and phosphatidylserine. Strain NFV-1 T had a DNA G + C content of 42.5 mol%, as evaluated according to the chromosomal DNA sequencing data. Analyses of sequence similarities and phylogeny based on the 16S rRNA genes, together with the housekeeping genes, gyrB , ftsZ , mreB , topA and gapA , indicated that the strain formed a distinct species-level lineage in the genus Vibrio of the family Vibrionaceae . These phylogenetic data and those from genomic and phenotypic characterisations support the establishment of a novel Vibrio species, for which the name Vibrio nitrifigilis sp. nov. (type strain NFV-1 T = BCRC 81211 T = JCM 33628 T ) is proposed.