Caproiciproducens puteiluti sp. nov. and Caproiciproducens lactatisolvens sp. nov., isolated from the pit mud of strong-flavour Baijiu distilleries

Two Gram-stain-positive, anaerobic, non-motile, non-spore-forming, rod-shaped bacteria, designated strains R1 T and R2 T , were isolated from pit mud. Both strains were oxidase-negative and catalase-negative. Strain R1 T grew at pH 5.0–9.0 (optimum 6.0–7.0), 25–45 °C (optimum 30–40 °C) and in 0–2.5 % NaCl. Strain R2 T grew at pH 5.0–10.0 (optimum 6.0–8.0), 25–45 °C (optimum 30–40 °C) and in 0–2.5 % NaCl. The major cellular fatty acids of both strains were C 14 : 0 , C 16 : 0 , summed feature 1 (C 15 : 1 iso H and/or C 13 : 0 3OH) and summed feature 3 (C 16 : 1 ω 7 c and/or C 16 : 1 ω 6 c ). Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phospholipids, unidentified polar lipids and glycolipids. The cell wall peptidoglycan contained meso -diaminopimelic acid. DNA G+C contents were 51.35 mol% (R1 T ) and 52.38 mol% (R2 T ). Based on 16S rRNA gene sequences, strains R1 T and R2 T exhibited sequence similarities of 98.53% and 98.19% to ‘ Caproiciproducens faecalis ’ AGMB10547 T and 96.68% and 96.48% to Caproiciproducens galactitolivorans BS-1 T , respectively. The orthologous average nucleotide identity values/digital DNA–DNA hybridization values with closest relatives (≤84.62%/≤28.90%) fell below prokaryotic species thresholds, while genome-based relatedness between novel strains (94.21%/58.00%) supported separate species status. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strains R1 T and R2 T represent two novel species of Caproiciproducens , for which the names Caproiciproducens puteiluti sp. nov. and Caproiciproducens lactatisolvens sp. nov. are proposed, respectively. The type strains of C. puteiluti and C. lactatisolvens are R1 T (=GDMCC 1.5535 T =KCTC 25972 T ) and R2 T (=GDMCC 1.5536 T =KCTC 25973 T ), respectively.