Daquilactobacillus linshuiensis gen. nov., sp. nov., a novel lactic acid bacterium isolated from Nongxiangxing Baijiu Daqu

A facultatively anaerobic, Gram-stain-positive, non-spore-forming, non-motile, short-rod-shaped lactic acid bacterium, designated strain DQM5ᵀ, was isolated from Nongxiangxing Baijiu Daqu, a traditional Chinese fermentation starter. On the basis of 16S rRNA gene sequence similarity, strain DQM5ᵀ exhibited the highest similarity to Companilactobacillus mishanensis (93.87%). In the 16S rRNA gene-based phylogenetic tree, strain DQM5ᵀ formed a distinct lineage located between the Companilactobacillus and Latilactobacillus clades. Phylogenomic analysis revealed that the average amino acid identity, average nucleotide identity and digital DNA–DNA hybridization values between strain DQM5ᵀ and its most closely related taxa were at most 58.6%, 70.1% and 26.5%, respectively, which are well below the thresholds for genus and species delineation. Notably, the genome size (1.40 Mbp) and DNA G+C content (30.8 mol%) of strain DQM5ᵀ are significantly different from those of related taxa. The peptidoglycan contains lysine as the diagnostic diamino acid. The major cellular fatty acids are C ₁₈:₁ ω9c and C ₁₆:₀ . These distinctive genomic features, together with other phenotypic, chemotaxonomic and phylogenetic differences, provide strong evidence for proposing a completely new genus. Therefore, strain DQM5ᵀ represents a novel species of a new genus within the family Lactobacillaceae , for which the name Daquilactobacillus linshuiensis gen. nov., sp. nov. is proposed. The type strain is DQM5ᵀ (=GDMCC 1.5776ᵀ=JCM 38144ᵀ).