Clostridium swellfunianum sp. nov., a novel anaerobic bacterium isolated from the pit mud of Chinese Luzhou-flavor liquor production

A novel Gram-positive, strictly anaerobic, spore-forming, rod-shaped bacterium, designated strain S11-3-10ᵀ, was isolated from the pit mud used for Chinese Luzhou-flavor liquor production. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that the strain formed a monophyletic clade with the closely related type strains of Clostridium cluster I and was most closely related to Clostridium amylolyticum JCM 14823ᵀ (94.38 %). The temperature, pH, and NaCl range for growth was determined to be 20–45 °C (optimum 37 °C), 4.0–10.0 (optimum pH 7.3), and 0–3.0 % (w/v), respectively. The strain was able to tolerate up to 7.5 % (v/v) ethanol. Yeast extract or peptone was found to be required for growth. Acids were found to be produced from glucose, mannose and trehalose. The major end products from glucose fermentation were identified as ethanol, acetate and hydrogen. The polar lipids were found to consist of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and unidentified phospholipids and polar lipids. The major fatty acids (>5 %) were identified as iso-C₁₅:₀, C₁₆:₀, C₁₆:₀ dma, C₁₄:₀, anteiso-C₁₅:₀ and iso-C₁₃:₀. No respiratory quinone was detected. The diamino acid in the cell wall peptidoglycan was identified as meso-diaminopimelic acid and the whole-cell sugars were found to include galactose and glucose as major components. The DNA G+C content was determined to be 36.4 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic evidence, the isolate is considered to represent a novel species of the genus Clostridium for which the name Clostridium swellfunianum sp. nov. is proposed. The type strain is S11-3-10ᵀ (=DSM 27788ᵀ = JCM 19606ᵀ = CICC 10730ᵀ).