%0 Journal Article %A Iino, Takao %A Mori, Koji %A Uchino, Yoshihito %A Nakagawa, Tatsunori %A Harayama, Shigeaki %A Suzuki, Ken-ichiro %T Ignavibacterium album gen. nov., sp. nov., a moderately thermophilic anaerobic bacterium isolated from microbial mats at a terrestrial hot spring and proposal of Ignavibacteria classis nov., for a novel lineage at the periphery of green sulfur bacteria %D 2010 %J International Journal of Systematic and Evolutionary Microbiology, %V 60 %N 6 %P 1376-1382 %@ 1466-5034 %R https://doi.org/10.1099/ijs.0.012484-0 %K ML, maximum-likelihood %K NJ, neighbour-joining %K MP, maximum-parsimony %I Microbiology Society, %X A moderately thermophilic chemoheterotrophic bacterium, strain Mat9-16T, was isolated from microbial mats developed in hot spring water streams from Yumata, Nagano, Japan. Cells of strain Mat9-16T were strictly anaerobic, Gram-stain-negative, non-sporulating, non-motile and short to long rods (2.0–15.5 μm in length). Strain Mat9-16T grew fermentatively with optimum growth at 45 °C, pH 7.0–7.5 and 1 % NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene revealed that strain Mat9-16T was affiliated with an uncultivated lineage, and the nearest cultivated neighbours were green sulfur bacteria belonging to the class Chlorobea with 77–83 % sequence similarity. However, strain Mat9-16T could not grow phototrophically and did not possess light-harvesting structures, morphologically and genetically, such as the chlorosomes of green sulfur bacteria. On the basis of phenotypic features and phylogenetic position, a novel genus and species are proposed for strain Mat9-16T, to be named Ignavibacterium album gen. nov., sp. nov. (=NBRC 101810T =DSM 19864T). We also propose to place the cultivated bacterial lineage accommodating the sole representative Mat9-16T in a novel class, Ignavibacteria classis nov. In addition, we present a formal description of the phylum-level taxon ‘Chlorobi’ as Chlorobi phyl. nov. %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.012484-0