Lentilactobacillus terminaliae sp. nov., isolated from tree bark (Terminalia ivorensis Chev.) and its antioxidant activity.

Abstract

A Gram-stain-positive, facultatively anaerobic, rod-shaped strain, designated SPB1-3^T, was isolated from tree bark. This strain exhibited heterofermentative production of dl-lactic acid from glucose. Optimal growth was observed at 25-40 °C, pH 4.0-7.0, and in the presence of 3% (w/v) NaCl. The cell wall peptidoglycan contained lysine and aspartic acid. The predominant fatty acids identified were C_16:0 and the Summed feature 7 (C_19 :1  ω7c/C_19:1  ω6c and/or C_19:1  ω6c/ω7c/19cy). The polar lipid profile included phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol, along with two unidentified phospholipids, two unidentified amino lipids and two unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences positioned strain SPB1-3^T within the genus Lentilactobacillus, showing a close relation to Lentilactobacillus kosonis NBRC 111893^T (99.86%) and Lentilactobacillus curieae CCTCC M 2011381^T (98.65%). The whole genome of strain SPB1-3^T comprised 1 932 998 base pairs with 1955 coding genes and a DNA G+C content of 37.8%. Digital DNA-DNA hybridization between strain SPB1-3^T and closely related type strains ranged from 19.50 to 27.20%. The average nucleotide identity ranged from 84.21 to 85.56%, and the average amino acid identity ranged from 57.25 to 85.99%, both falling below the established thresholds for species delineation. Strain SPB1-3^T was clearly distinguishable from related Lentilactobacillus species based on its phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence similarity and whole genome analysis. Additionally, the strain exhibited radical scavenging activity at 66.92% and demonstrated 82.32% inhibition in the tyrosinase inhibitory assay. These findings support the classification of strain SPB1-3^T as a novel species within the genus Lentilactobacillus, for which the name Lentilactobacillus terminaliae sp. nov. is proposed. The type strain is SPB1-3^T (=JCM 35081^T=TISTR 10005^T).