Muricauda aurea sp. nov. and Muricauda profundi sp. nov., two marine bacteria isolated from deep sea sediment of Pacific Ocean

Two novel Gram-stain-negative, aerobic, rod-shaped, carotenoid-pigmented and non-flagellated bacteria, designated BC31-1-A7(T) and BC31-3-A3(T), were isolated from polyethylene-terephthalate-degrading bacterial consortia enriched from deep-sea sediment collected in the Pacific Ocean. Optimal growth of both strains was observed at 28-32 degrees C, at pH 7.5 and in the presence of 3-4% (w/v) NaCl. The 16S rRNA gene sequence analysis revealed that strains BC31-1-A7(T) and BC31-3-A3(T) were closely related to Muricauda aquimarina JCM 11811(T), Muricauda lutimaris KCTC 22173(T), Muricauda ruestringensis DSM 13258(T), Muricauda zhangzhouensis DSM 25030(T), Muricauda oceani JCM 33902(T) and Muricauda oceanensis KCTC 72200(T) with 96.8-98.9% sequence similarity. The 16S rRNA gene sequence similarity between strains BC31-1-A7(T) and BC31-3-A3(T) was 97.5%. The genomic G+C contents of strains BC31-1-A7(T) and BC31-3-A3(T) were 42.1 and 41.6 mol%, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain BC31-3-A3(T), strain BC31-1-A7(T) and their six closely related type strains were 77.6-84.3% and 20.5-27.9%, respectively. Menaquinone-6 was detected as the major isoprenoid quinone in all strains. Their major fatty acids were iso-C-15:0, iso-C-15:1 G and iso-C-17:0 3-OH. The major polar lipids of strains BC31-1-A7(T) and BC31-3-A3(T) were identified as one phosphatidylethanolamine, some unidentified polar lipids and one aminolipid. Based on their distinct taxonomic characteristics, strains BC31-1-A7(T) and BC31-3-A3(T) represent two novel species in the genus Muricauda. The names proposed to accommodate these two strains are Muricauda aurea sp. nov. and Muricauda profundi sp. nov., and the type strains are BC31-1-A7(T) (=MCCC M23246(T)=KCTC 82569(T)) and BC31-3-A3(T) (=MCCC M23216(T)=KCIC 82302(T)), respectively.