Lactobacillus corticis sp. nov., isolated from hardwood bark.

Abstract

During a study on the biodiversity of bacteria that inhabit woody biomass, we isolated a strain coded B40T from hardwood bark used as a compost ingredient in Japan. The strain, characterized as B40T, is a Gram-stain-positive, rod-shaped, non-motile, non-spore-forming and catalase-negative bacterium. This novel isolate showed growth at 30-50 °C, at pH 3.5-7.5 and in the presence of up to 4 % (w/v) NaCl. Its major fatty acids include C16:0, C18:1 ω9c and summed feature 8. The genomic DNA G+C content of strain B40T is 42.2 mol%. Results of 16S rRNA gene sequence-based phylogenetic analysis indicated that strain B40T belongs to the genus Lactobacillus and the closest neighbours of strain B40T are Lactobacillus gigeriorum 202T (95.7 %), Lactobacillus pasteurii CRBIP 24.76T (95.6 %), Lactobacillus psittaci DSM 15354T (95.4 %), Lactobacillus fornicalis TV1018T (95.4 %) and Lactobacillus jensenii ATCC 25258T (95.2 %). The amino acid sequence-based phylogenetic analyses of 489 shared protein-encoding genes showed that the strain forms a phylogenetically independent lineage in the genus Lactobacillus but could not be assigned to any known species. Strain B40T has an average nucleotide identify of <70.2 % and a digital DNA-DNA hybridization value of 19.2 % compared with the strains of other closely related Lactobacillus species. Differential genomic, phenotypic and chemotaxonomic properties, in addition to phylogenetic analyses, indicated that strain B40T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus corticis sp. nov. is proposed. The strain type is B40T (=JCM 32597T=DSM 107967T).