sp. nov., a thermophilic, nitrogen-fixing fermentative bacterium isolated from a terrestrial hot spring in Japan.

A novel nitrogen-fixing fermentative bacterium, designated as YA01, was isolated from Nakabusa hot springs in Japan. The short-rod cells of strain YA01 were Gram-positive and non-sporulating. Phylogenetic trees of the 16S rRNA gene sequence and concatenated sequences of 40 single-copy ribosomal genes revealed that strain YA01 belonged to the genus and was closely related to 108, DSM 6725 and 2002. The 16S rRNA gene sequence of strain YA01 shares less than 98.1 % identity to the known species. The G+C content of the genomic DNA was 34.8 mol%. Strain YA01 shares low genome-wide average nucleotide identity (90.31-91.10 %), average amino acid identity (91.45-92.10 %) and <70 % digital DNA-DNA hybridization value (41.8-44.2 %) with the three related species of the genus . Strain YA01 grew at 50-78 °C (optimum, 70 °C) and at pH 5.0-9.5 (optimum, pH 6.5). Strain YA01 mainly produced acetate by consuming d(+)-glucose as a carbon source. The main cellular fatty acids were iso-C (35.7 %), C (33.3 %), DMA (6.6 %) and iso-C (5.9 %). Based on its distinct phylogenetic position, biochemical and physiological characteristics, and the major cellular fatty acids, strain YA01 is considered to represent a novel species of the genus for which the name sp. nov. is proposed (type strain YA01=DSM 112098=JCM 34253).