An anaerobic, Gram-stain-positive, spore-forming bacterium, designated strain PYR-10T, was isolated from a mesophilic methanogenic consortium. Cells were 0.7-1.2×6.0-6.3 µm, straight or slightly curved rods, with flagellar motility. Growth was observed in PYG (peptone-yeast glucose) medium at pH 5.5-8.0 (optimum, pH 6.5), 30-55 °C (45 °C) and in NaCl concentrations of 0-15 g l-1 (0 g l-1). Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain PYR-10T belongs to the genus Clostridium. The strain showed 95.4, 93.7, 93.5 and 93.0 % 16S rRNA gene sequence similarity to Clostridium swellfunianum DSM 27788T, Clostridium pascui DSM 10365T, Clostridium pasteurianum DSM 525T and Clostridium punense DSM 28650T, respectively. The genomic DNA G+C content was 27.7 mol%. The major cellular fatty acids of strain PYR-10T were iso-C15 : 0, C16 : 0, C16 : 0 DMA, anteiso-C15 : 0 and C14 : 0. The main polar lipids were glycolipid, phosphoaminoglycolipid, diphosphatidylglycerol, phosphatidylglycerol, phospholipids, phosphatidylethanolamine and lipids. An unknown menaquinone was detected. 2,6-Diaminopimelic acid was not detected. The whole-cell sugars contained ribose and lower amounts of glucose. Based on the results of phylogenetic, chemotaxonomic and phenotypic analyses, strain PYR-10T represents a novel species of the genus Clostridium, for which the name Clostridium prolinivorans sp. nov. is proposed. The type strain is strain PYR-10T (=JCM 33161T=CCAM 531T=CGMCC 1.5286T).
Keywords: Clostridium; Clostridium prolinivorans; saccharolytic; thermophilic.