Chryseobacterium vaccae sp. nov., isolated from raw cow's milk

초록

Strain CA7(T), a Gram-stain-negative, non-motile, non-spore-forming, aerobic and rod-shaped bacterial strain, was isolated from raw cow's milk collected from a farm affiliated with Chung-Ang University, Anseong, Korea. and characterized by a polyphasic approach. Optimal growth of strain CA7(T) was observed on tryptic soy agar at 30 degrees C and pH 7.0 with 0% NaCl. Phylogenetic analysis based on the 165 rRNA gene sequence revealed that strain CA7(T) belonged to the genus Chryseobacterium. The most closely related strains (165 rRNA gene sequence similarity indicated in parentheses), based on the phylogenetic analysis, were Chryseobacterium rhizosphaerae KCTC 22548(T) (98.08%), Chryseobacterium nakagawai CCUG 60563(T) (98.61%), Chryseobacterium jejuense KACC 12501(T) (97.85%) and Chryseobacterium aurantiacum KCTC 62135(T) (97.78%). Whole genome sequencing indicated that the genome size was 5125723 by and had a DNA G+C content of 37.4 mol%. Average nucleotide identity values for strain CA7(T) with C. rhizosphaerae, C. nakagawai, C. jejuense, C. aurantiacum, and the type species of the genus Chryseobacterium, C. gleum, were 80.2, 79.8, 79.8, 79.6 and 80.4%, respectively. The digital DNA-DNA hybridization values of CA7(T) compared to C. rhizosphaerae, C. nakagawai. C. jejuense, C. aurantiacum and C. gleum were 24.1, 23.9, 23.9. 23.7 and 24.3%, respectively. The major fatty acids were iso-C-15(:0), summed feature 9 (iso-C-17:1 omega 9c and/or C-1(6:0) 10-methyl), iso-C-17:0 3-OH and summed feature 3 (iso-C-15(:0) 2-OH and/or C-16:1 omega 7c). Menaquinone-6 was the only respiratory quinone. The major polar lipid was phosphatidylethanolamine. Based on this polyphasic taxonomic study, strain CAT represents a novel species of the genus Chryseobacterium for which the name Chryseobacterium vaccae sp. nov. is proposed. The type strain is CA7(T) (=KACC 21402(T)=JCM 33749(T)).

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