Azospirillum fermentarium sp. nov., a nitrogen-fixing species isolated from a fermenter

An aerobic, Gram-stain-negative, spiral or rod-shaped, non-spore-forming, diazotrophic bacterium (strain CC-LY743T) was isolated from a fermentative tank in Taiwan. Strain CC-LY743T was able to grow at 20–37 °C and pH 6.0–8.0 and tolerated up to 3.0 % (w/v) NaCl. It was positive for nitrogen fixation, with activity of 10.6 nmol ethylene h−1. 16S rRNA gene sequence analysis of strain CC-LY743T showed highest similarity to Azospirillum picis DSM 19922T (96.1 %), Azospirillum oryzae JCM 21588T (96.0 %) and Azospirillum rugosum DSM 19657T (96.0 %) and lower similarity ( Azospirillum species. Highest nifH gene sequence similarities were obtained with Azospirillum brasilense BCRC 12270T (92.0 %), Azospirillum formosense BCRC 80273T (92.3 %) and A. rugosum DSM 19657T (91.8 %). It was positive in the rapid identification by a genus-specific primer set. The predominant quinone system was ubiquinone 10 (Q-10) and the DNA G+C content was 69.6±0.1 mol%. The major fatty acids found in strain CC-LY743T were n-C16 : 0, C19 : 0 cyclo ω8c, C14 : 0 3-OH/C16 : 1 iso I, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. Based on its phylogenetic, phenotypic and chemotaxonomic features, strain CC-LY743T is considered to represent a novel species within the genus Azospirillum for which the name Azospirillum fermentarium sp. nov. is proposed. The type strain is CC-LY743T ( = BCRC 80505T = JCM 18688T = LMG 27264T).