Flavobacterium magnesitis sp. nov. and Flavobacterium zubiriense sp. nov., two novel Flavobacterium species isolated from alkaline magnesite residues

Three bacterial strains, designated FZUC8N2.13 T , FBOR7N2.3 T and FZUR7N2.5, were isolated from distinct magnesite residues in Spain. Phylogenetic and phylogenomic analysis places them within the genus Flavobacterium . Strains FBOR7N2.3 T and FZUR7N2.5 share 100% of similarity in the 16S rRNA gene sequence, and both are most closely related to Flavobacterium cellulosilyticum AR-3-4 T with which they share 97.5% of 16S rRNA gene similarity. Strain FZUC8N2.13 T forms a distinct lineage most closely related to Flavobacterium lacustre IMCC36792 T with 97.7% 16S rRNA gene similarity. The closest phylogenomic neighbours of these three strains are Flavobacterium flevense DSM 1076 T , ‘ Flavobacterium undicola ’ BBQ-18 T and Flavobacterium commune PK15 T . The average nucleotide identity and digital DNA–DNA hybridization values between the three strains and closest members of the genus Flavobacterium are below the threshold values of 95% and 70%, respectively. Strains FZUC8N2.13 T , FBOR7N2.3 T and FZUR7N2.5 stain Gram-negative, are rod-shaped and form yellow colonies. Optimum growth occurs at 25 °C and pH 7. The genomic G+C contents are 33.4 mol% for strain FZUC8N2.13 T and 33.2 mol% for strains FBOR7N2.3 T and FZUR7N2.5. The major isoprenoid quinone is menaquinone 6. The major fatty acids are summed feature 3 (C 16 : 1 ω7c and/or C 16 : 1 ω6c) (22.6–31.1%), iso-C 15 : 0 (13.6–16.2 %) and anteiso-C 15 : 0 (8.7–10.5%). The polar lipids consist of two aminolipids, two aminophospholipids and one glycolipid. The phylogenetic, phylogenomic, phenotypic and chemotaxonomic data indicate that FZUC8N2.13 T , FBOR7N2.3 T and FZUR7N2.5 are distinct from the described species of Flavobacterium and should be classified as novel species, for which we propose the names Flavobacterium zubiriense for strain FZUC8N2.13 T (=UCCCB 179 T =CECT 30977 T ) and Flavobacterium magnesitis for strains FBOR7N2.3 T (=UCCCB 178 T =CECT 30976 T ) and FZUR7N2.5 (=UCCCB 216=CECT 31036).