A Gram-stain-negative, aerobic and rod-shaped strain, YLB-05T, was isolated from a sample of deep-sea sediment (depth, 6796 m) from the Yap Trench. It was motile, oxidase-positive and catalase-positive. Growth was observed at salinities of 1-12 % (NaCl, w/v), with the optimum at 5 %. The strain was able to thrive at low (4 °C) temperatures, with the optimum at 37 °C, but did not grow at 50 °C. The optimum pressure for growth was 0.1 MPa with tolerance up to 50 MPa. The 16S rRNA gene sequencing analysis showed that YLB-05T was most closely related to Marinomonas communis LMG 2864T (97.8 %). Phylogenetic analysis placed strain YLB-05T within the genus Marinomonas. The average nucleotide identity and the DNA-DNA hybridization values between strain YLB-05T and closely related type strains were below the respective thresholds for species differentiation. The principal fatty acids were C16 : 0, summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and summed feature 3 (C16 : 1ω7c/C16 : 1 ω6c). The DNA G+C content was 45.7 mol%. The respiratory quinone was determined to be Q-8. The polar lipids were an unidentified phospholipid and an unidentified aminophospholipid. The combined genotypic and phenotypic data showed that strain YLB-05T represents a novel species within the genus Marinomonas, for which the name Marinomonaspiezotolerans sp. nov. is proposed, with the type strain YLB-05T (=MCCC 1A12712T=KCTC 62812T).
Keywords: Marinomonas piezotolerans sp. nov.; Yap Trench; deep-sea sediment.