Caproicibacterium lactatifermentans sp. nov., isolated from pit clay used for the production of Chinese strong aroma-type liquor

Abstract

Two recently reported bacterial strains that were identified as the dominant caproate-producing bacteria in pit clay, were further characterized to determine their phylogeny and taxonomy. The two strains, designated as LBM19010 T and JNU-WLY1368, were short rod-shaped, Gram-stain-positive, non-motile and strictly anaerobic. Analysis of the 16S rRNA gene sequences revealed that strains LBM19010 T and JNU-WLY1368 shared a 16S rRNA gene sequence similarity of 99.93 % and belonged to a recent proposed genus Caproicibacterium in the family Oscillospiraceae . The proposed type strain, LBM19010 T , showed the highest 16S rRNA gene sequence similarity to Caproicibacterium amylolyticum LBM18003 T (96.34%), followed by Caproiciproducens galactitolivorans JCM 30532 T (94.14 %). The pairwise average nucleotide identity and average amino acid identity values between strains LBM19010 T and LBM18003 T were 74.84 and 76.18 %, respectively. Growth of strain LBM19010 T occurred at pH 4.5–7.5 (optimum, pH 5.0–5.5), 20–40 °C (optimum, 35 °C) and with 0–1 % (w/v) NaCl (optimum, 0 %). Strains LBM19010 T and JNU-WLY1368 were both able to ferment several hexoses, disaccharides, starch and lactate but not pentoses. Caproate and butyrate were the major end-products from glucose. The predominant cellular fatty acids (>10 %) of strain LBM19010 T were C 16 : 0 (56.3 %), C 14 : 0 DMA (19.5 %) and C 14 : 0 (14.9 %). The identified polar lipids of strain LBM19010 T were diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids and nine unidentified glycolipids. Based on phylogenetic, phenotypic and chemotaxonomic evidence, strains LBM19010 T and JNU-WLY1368 belong to a novel species of the genus Caproicibacterium , for which the name Caproicibacterium lactatifermentans sp. nov. is proposed. The type strain is LBM19010 T (=GDMCC 1.1627 T =JCM 33782 T ).

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