A Gram-stain-positive, catalase-negative, rod-shaped, non-motile, non-spore-forming, and facultatively anaerobic strain CRM56-3T, isolated from fermented tea leaves collected from Chiang Rai province, Thailand, was characterized based on a polyphasic approach. The strain produced dl-lactic acid heterofermentatively from glucose. It grew at 15-42 °C (optimum at 30 °C), pH 3.5-8.0 (optimum pH 6.0) and in 1-4 % (w/v) NaCl. Strain CRM56-3T contained C16:0, C19:0 cyclo ω8c, and C18:1 ω7c, and/or C18:1 ω6c as major cellular fatty acids. Based on 16S rRNA gene sequence analysis, strain CRM56-3T belongs to the genus Secundilactobacillus and was closely related to Secundilactobacillus odoratitofui DSM 19909T (99.2 %), S. collinoides JCM 1123T (98.9 %), and S. paracollinoides DSM 15502T (98.7 %). The draft genome of strain CRM56-3T contained 2681617 bp with 2413 coding sequences and DNA G+C content determined from genome sequence of 44.5 mol%. The digital DNA-DNA hybridization (dDDH) between strain CRM56-3T and S. odoratitofui DSM 19909T, S. collinoides JCM 1123T, and S. paracollinoides DSM 15502T were 19.5, 20.4, and 21.6 %, respectively. The average nucleotide identity (ANIm) and the average amino acid identity (AAI) between strain CRM56-3T and closely related strains were lower than 85.0 and 80.0 %, respectively. The strain CRM56-3T was clearly distinguished from related Secundilactobacillus species by its phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence similarity, and the draft genome analysis. Therefore, the strain represents a novel species of the genus Secundilactobacillus, for which the name of Secundilactobacillus folii sp. nov. is proposed. The type strain is CRM56-3T (=JCM 34223T=LMG 31663T=TISTR 2851T).
Keywords: Secundilactobacillus folii; fermented tea leaves; lactic acid bacteria; polyphasic.