Microcella flavibacter sp. nov., isolated from marine sediment, and reclassification of Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov.

A novel Gram-staining positive, aerobic, rod-shaped, non-motile and yellow-pigmented actinobacterium, designated strain WY83, was isolated from a marine sediment of Indian Ocean. Strain WY83 grew optimally at 30-35 °C, pH 7-8 and with 0-3% (w/v) NaCl. The predominant menaquinones were MK-10, MK-11 and MK-12, and the major fatty acids were C ω9c/C19:1 ω11c, anteiso-C, C 3OH, and iso-C. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid. The cell-wall peptidoglycan contained lysine as a diamino acid. The DNA G + C content was 72.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and ninety-two bacterial core genes indicated that strain WY83 formed an evolutionary lineage with Chryseoglobus frigidaquae JCM 14730, Chryseoglobus indicus CTD02-10-2, Yonghaparkia alkaliphila JCM 15138, Microcella alkaliphila DSM 18851 and Microcella putealis DSM 19627 within the radiation enclosing members of the family Microbacteriaceae. All pairwise percentage of conserved proteins between strain WY83 and the closely related phylogenetic neighbors were greater than 65%. The average nucleotide identity and in silico DNA-DNA hybridization values were both below the thresholds used for the delineation of a new species. On the basis of the evidence presented, strains WY83, Y. alkaliphila JCM 15138, C. frigidaquae JCM 14730, M. alkaliphila DSM 18851 and M. putealis DSM 19627 should belong to different species of the same genus. Strain WY83 represents a novel species of the genus Microcella, for which the name Microcella flavibacter sp. nov. is proposed. The type strain is WY83 (= KCTC 39637 = MCCC 1A07099). Furthermore, Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila were reclassified as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov., respectively.