Caproicibacterium argilliputei sp. nov., a novel caproic acid producing anaerobic bacterium isolated from pit clay

An anaerobic, Gram-positive, rod-shaped, motile and spore-forming bacterium, designated strain ZCY20-5 T , was isolated from pit clay of Chinese strong-aroma type Baijiu (Chinese liquor). Phylogenetic analyses based on 16S rRNA gene and genome sequences showed that strain ZCY20-5 T belonged to the genus Caproicibacterium , family Oscillospiracheae , but it showed low similarity to the type species Caproicibacterium amylolyticum LBM18003 T (98.00 %) and Caproicibacterium lactatifermentans LBM19010 T (95.67 %). In anaerobic yeast extract medium, growth was observed at 20–45 °C (optimum, 35–40 °C), at pH 4.0–9.0 (optimum, pH 6.5–7.0) and with 0.0–2.0 % NaCl (w/v). The predominant fatty acids were C 16 : 0 , C 14 : 0 , C 13 3-OH and C 16 3-OH, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, three phospholipids of unknown structure containing glucosamine and two unidentified phospholipids. Strain ZCY20-5 T exhibited an 81.32 % pairwise average nucleotide identity value, a 78.98 % average amino acid identity value and a 22.30 % digital DNA–DNA hybridization value compared to its closest relative C. amylolyticum LBM18003 T . Based on morphological, physiological, biochemical, chemotaxonomic, genotypic and phylogenetic results, strain ZCY20-5 T represents a novel species of Caproicibacterium , and the type strain is ZCY20-5 T (=MCCC 1A19399 T =KCTC 25590 T ).