Azoarcus taiwanensis sp. nov., a denitrifying species isolated from a hot spring

The strain NSC3^T, a novel, facultative, chemolithotrophic, denitrifying, alkaliphilic, sulfide-oxidizing bacterium isolated from a hot spring in Yang-Ming Mountain, Taiwan, was Gram negative, rod shaped, and motile by single polar flagella and grew facultatively by adopting a denitrifying metabolism. The 16S rRNA sequence analysis revealed that strain NSC3^T belongs to beta subclass of the Proteobacteria and most closely related to Azoarcus evansii KB740^T (95.44 %), Azoarcus toluvorans Td-21^T (95.21 %), Azoarcus tolulyticus Tol-4^T (95.08 %), and Azoarcus toluclasticus MF63^T (94.94 %). The phylogenetic analyses based on 16S rRNA gene sequences indicated that the strain NSC3^T formed a distinct lineage in the Betaproteobacteria and that it exhibited the highest level of sequence similarity with species of the genera Azoarcus (95.28–93.13 %). The major fatty acids of the type strain were C_16:0 (26.9 %), C_16:1w7c (28.9 %), C_18:0 (9.6 %), and C_18:1w7c/w6c (29.9 %). The DNA G+C content of genomic DNA was 63.7 mol%. On the basis of the 16S rRNA sequence similarity, phenotypic and genotypic characteristics, and chemotaxonomic data, the strain NSC3^T could be differentiated from other species of the genus Azoarcus. Therefore, strain NSC3^T (equal to BCRC 80111^T and DSM 24109^T) is proposed as a novel species in genus Azoarcus, for which the name Azoarcus taiwanensis sp. nov. is proposed. The strain NSC3^T is deposited in Bioresource Collection and Research Center, Taiwan, under the reference number BCRC 80111^T, and German Collection of Microorganisms and Cell Cultures, Germany (DSMZ), with DSM 24109^T.