Lentilactobacillus laojiaonis sp. nov., isolated from the mud in a fermentation cellar for the production of Chinese liquor

Abstract

A novel Gram-stain-positive, rod-shaped, non-motile bacterial strain, designated IM3328T, was isolated from a mud cellar which has been continuously used over hundreds of years for the fermentative production of Chinese strong-flavour baijiu. It is asporogenous, facultative anaerobic and does not exhibit catalase activity. Strain IM3328T can grow at pH 4.5–8.5 (optimum, pH 7.0), 15–45 °C (optimum, 37 °C), with 0–75% (w/v) ethanol with and 0–6% (w/v) NaCl. The API 50CH assay revealed that strain IM3328T can metabolize l-arabinose, d-ribose, d-xylose, d-glucose, d-fructose, d-mannose, N-acetylglucosamine, gluconate, methyl β-d-pyranoside, methyl α-d-glucopyranoside, methyl α-d-glucopyranoside and raffinose among the 49 studied carbon sources. Lactic acid, acetic acid, ethanol, isopentanol and butyl acetate are he predominant metabolites in the fermentation broth of strain IM3328T when cultured in liquid de Man, Rogosa and Sharpe medium under micro-aerobic or anaerobic conditions. The polar lipids of strain IM3328T consist of diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid, two unidentified glycolipids and two unidentified lipids. The major cellular fatty acids (≥10%) consist of C16 : 0, C18:1 ω9c and summed feature 7. The cell wall contains ribose, glucose, galactose, lysine, alanine, glutamic acid and aspartic acid. The complete genome of strain IM3328T contains a circular chromosome of 1242019 bp with 1242 genes and 33 mol% G+C content. On the basis of the 16S rRNA gene phylogenetic tree, Lentilactobacillus senioris DSM 24302T (95.9% similarity), Lentilactobacillus rapi DSM 19907T (95.7% similarity) and Lentilactobacillus parabuchneri DSM 5707T (95.1% similarity) were chosen to compare with strain IM3328T to reveal the physiological differences. The low average nucleotide identity values (69.7–71.2%) between strain IM3328T and phylogenetically related reference strains demonstrated that this strain represents a novel species of the genus Lentilactobacillus , and the name Lentilactobacillus laojiaonis sp. nov. (type strain IM3328T=CGMCC 1.18832T=JCM 34630T) is proposed.