Microbacterium chionoecetis sp. nov. and Agrococcus chionoecetis sp. nov.: Novel Gut Bacteria from Red Snow Crab.

Two yellow-coloured, Gram-stain-positive, oxidase-negative, aerobic, non-motile, and rod-shaped strains, labelled as ProA8^T and ProA11^T, were isolated from digestive tract of red snow crab (Chionoecetes japonicus). Strain ProA8^T grow at temperature range of 15-35°C, while strain ProA11^T grow at temperature range of 15-40°C. Phylogenetic and 16S rRNA gene sequence analysis revealed that strains ProA8^T and ProA11^T belonged to the genera Microbacterium and Agrococcus, respectively. Strain ProA8^T was closely affiliated with Microbacterium yannicii JCM 18959^T (98.8%) and strain ProA11^T was most closely related to Agrococcus baldri IAM 15147^T (98.9%). The genome sizes of ProA8^T and ProA11^T were 4,373,776 bp and 2,665,899 bp, with DNA G+C contents of 70.5% and 70.1%, respectively. The genomic relatedness values of ProA8^T and ProA11^T with their respective reference strains were <32.0% (for digital DNA-DNA hybridization) and <87.0% (for average nucleotide identity). Biosynthetic gene analysis showed the presence of genes for resorcinol production in ProA8^T and ectoine biosynthesis in ProA11^T, indicating ecological and biotechnological significance. Virulence analyses determined that strains ProA8^T and ProA11^T were non-pathogenic to humans, highlighting their safe application in biotechnological field. The major cellular fatty acids reported in ProA8^T and ProA11^T were anteiso-C_15:0, iso-C_16:0, and anteiso-C_17:0. Overall, the polyphasic taxonomic data suggest that both strains ProA8^T and ProA11^T represent two novel species within the genera Microbacterium and Agrococcus, respectively. Accordingly, we propose the names Microbacterium chionoecetis sp. nov., with the type strain ProA8^T (= KCTC 49861^T = JCM 37392^T) and Agrococcus chionoecetis sp. nov., with the type strain ProA11^T (= KCTC 49958^T = JCM 37393^T).