Clostridium huakuii sp. nov., a novel anaerobic acetogenic bacterium isolated from methanogenic consortia.
A Gram-staining-positive, spore-forming, obligate anaerobic acetogenic bacterium, designated LAM1030 (T), was isolated from methanogenic consortia enriched from biogas slurry collected from the large-scale anaerobic digester of Modern Farming Corporation in Hebei Province, China. Cells of strain LAM1030(T) were motile, straight or spiral-rod-shaped. Strain LAM1030(T) could utilize glucose, fructose, maltose, galacatose, lactose, sucrose, cellobiose?mannitol, pyruvate, succinic acid, tryptophan as sole carbon source. Acetic acid, isovaleric acid and butanoic acid were the main productions of glucose fermentation. Sodium sulfite was used as electron acceptor. Growth of strain LAM1030(T) was completely inhibited by the addition of 20 ?g/ml of ampicillin, tetracycline, gentamicin and erythromycin. The main polar lipids of strain LAM1030(T) were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and eleven unknown glycolipids and two unknown phospholipids. No respiratory quinone was detected. The major fatty acids of strain LAM1030(T) were C16:0 (21.1%), C14:0 (10.3%) and iso-C15:0 (6.6%). The analysis on the 16S rRNA gene sequence indicated that strain LAM1030(T) belonged to the genus Clostridium and was most closely related to C. subterminale DSM 6970(T), C. thiosulfatireducens DSM 13105(T) and C. sulfidigenes DSM 18982(T), with 97.0%, 96.9% and 96.8% similarity, respectively. The G+C content of the genomic DNA of strain LAM1030(T) was 31.2±0.3 mol%. On the basis of its phenotypic, phylogenetic and chemotaxonomic characterization, strain LAM1030(T) was suggested to represent a novel species of the genus Clostridium , for which the name Clostridium huakuii sp. nov. is proposed. The type strain is LAM1030(T) (=ACCC 00698(T) = JCM 19186(T)).