Three Gram-negative, aerobic, non-spore-forming, oval- to pear-shaped bacterial strains (T16B2(T), T24B3, and C76AD) were isolated from petroleum-degrading microbial communities through an enrichment of sediments and seawater samples from the Pacific Ocean. Phylogenetic analysis showed strains T16B2(T), T24B3, and C76AD to form a robust clade together with Hyphomonas atlanticus 22II1-22F38(T) and Hyphomonas beringensis 25B14_1(T) (16S rRNA identity ≥99.6 %). Genomic average nucleotide identity and DNA-DNA hybridization estimate values between strain T16B2(T) and nine type strains of the genus Hyphomonas are in the range of 82.9-88.2 and 18.3-33.6 %, respectively. The major cellular fatty acids in strains T16B2(T), T24B3, and C76AD are C16:0, C17:0, C18:1 ω7c-methyl, and summed feature 8 (C18:1 ω6c/ω7c). The DNA G+C content of strain T16B2(T) is 58.5 %. The predominant respiratory quinone of strain T16B2(T) is Q-11. Polar lipids comprise three unidentified glycolipids, one unidentified phospholipid, and two polar lipids. Combined phenotypic and genotypic data show strains T16B2(T), T24B3, and C76AD to represent a novel species of the genus Hyphomonas, for which the name Hyphomonas pacifica sp. nov. is proposed, with type strain T16B2(T) (=LMG 27911(T) = MCCC 1A04387(T)).
Keywords: Deep-sea; Hyphomonas pacifica sp. nov.; Pacific Ocean; Taxonomy.