A novel anaerobic, endospore-forming bacterium (strain M08 DMBT) was isolated from a terrestrial mud volcano (Taman Peninsula, Russia). Cells of the strain were motile rods 1.3-2.0 µm long and 0.4 µm in diameter. The temperature range for growth was 5-42 °C, with an optimum at 30 °C. The pH range for growth was H 6.5-11.0, with an optimum at pH 8.0. Growth of strain M08 DMBT was observed at NaCl concentrations of 0-5.0 % (w/v) with an optimum at 1.0 %. Strain M08 DMBT utilized 3,4-dimethoxybenzoic acid, 2-methoxyphenol, carbon monoxide, glucose, fructose, mannose, xylose and yeast extract. The end product of glucose fermentation was acetate. The DNA G+C content of strain M08 DMBT was 32.3 mol% (obtained via whole genome sequencing). The closest phylogenetic relative of strain M08 DMBT was Alkalibaculum bacchi (family Eubacteriaceae, class Clostridia) with 95.17 % 16S rRNA gene sequence similarity. Based on the phenotypic, genotypic and phylogenetic characteristics of the isolate, strain M08 DMBT is considered to represent a novel species of the genus Alkalibaculum, for which the name Alkalibaculum sporogenes sp. nov. is proposed. The type strain of Alkalibaculum sporogenes is M08 DMBT (=KCTC 15840T=VKM B-3387T).
Keywords: Eubacteriaceae; acetogen; endospores; methoxylated aromatic compounds.