Arthrobacter bussei sp. nov., a pink-coloured organism isolated from cheese made of cow's milk

A pink-coloured bacterium (strain KR32(T)) was isolated from cheese and assigned to the 'Arthrobacter agilis group'. Members of the 'pink Arthrobacter agilis group' form a stable Glade (100% bootstrap value) and contain the species Arthrobacter agilis, Arthrobacter ruber and Arthrobacter echini, which share >= 99.0% 16S rRNA gene sequence similarity. Isolate KR32(T) showed highest 16S rRNA gene sequence similarity (99.9 %) to A. agilis DSM 20550(T). Additional multilocus sequence comparison confirmed the assignment of strain KR32(T) to the Glade 'pink A. agilis group'. Average nucleotide identity and digital DNA-DNA hybridization values between isolate KR32(T) and A. agilis DSM 20550(T) were 82.85 and 26.30%, respectively. The G+C content of the genomic DNA of isolate KR32(T) was 69.14 mol%. Chemotaxonomic analysis determined anteiso-C-15:0 as the predominant fatty acid and MK-9(H-2) as the predominant menaquinone. Polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and monoacyldimannosyl-monoacylglycerol. The peptidoglycan type of the isolate was A3 alpha. The carotenoid bacterioruberin was detected as the major pigment. At 10 degrees C, strain KR32(T) grew with increased concentrations of bacterioruberin and production of unsaturated fatty acids. Strain KR32(T) was a Gram-stain-positive, catalase-positive, oxidase-positive and coccus-shaped bacterium with optimal growth at 27-30 degrees C and pH 8. The results of phylogenetic and phenotypic analyses enabled the differentiation of the isolate from other closely related species of the 'pink A. agilis group'. Therefore, strain KR32(T) represents a novel species for which the name Arthrobacter bussei sp. nov. is proposed. The type strain is KR32(T) (=DSM 109896(T)=LMG 31480(T)=NCCB 100733(T)).