A Gram-stain-negative, long-rod-shaped and facultative aerobic bacterium, designated HB-1T, was isolated from a round hay bale at the Kansas State University Beef Stocker Unit. The results of phylogenetic analysis of 16S rRNA gene sequences indicated that strain HB-1T clustered within the genus Gemmobacter and its closest relatives were Gemmobacter aquaticus A1-9T (98.0 %), Gemmobacter lutimaris YJ-T1-11T (98.0 %), Gemmobacter fontiphilus JS43T (97.8 %), Gemmobacter aquatilis DSM 3857T (97.5 %) and Gemmobacter lanyuensis Orc-4T (96.9 %). Additional phylogenomic analysis also indicated that strain HB-1T belongs to the genus Gemmobacter. The draft genome of strain HB-1T had a total length of 4.23 Mbp and contained 4071 protein-coding genes. The average nucleotide identity values between the genomes of strain HB-1T and the three most-related type strains ranged from 77.5 to 78.1 %. The DNA G+C content of strain HB-1T was 63.7 mol%. The novel strain grew at 10-37 °C, pH 5-10 and with 0-2 % NaCl. Oxidase and catalase activities were positive. Cells were 0.3-0.4 µm wide, 3.0-7.0 µm long and usually found in pairs or chains of cells. The major respiratory quinone of strain HB-1T was Q-10 (90 %), with a minor amount of Q-9 (10 %). The major fatty acids were C18 : 1 ω7c (54.6 %) and C16 : 0 (18.2 %). On the basis of phenotypic, phylogenetic and chemotaxonomic data, strain HB-1T (=DSM 109828T=ATCC TSD-211T) is considered to represent a novel species of the genus Gemmobacter, for which the name Gemmobacter serpentinus sp. nov. is proposed.
Keywords: anaerobic growth; conserved forage; fermentation genes.