Marinifaba aquimaris gen. nov., sp. nov., a novel chitin‐degrading gammaproteobacterium in the family Alteromonadaceae isolated from seawater of the Mariana Trench

A novel Gram-negative, rod-shaped, aerobic, oxidase-positive and catalase-negative bacterium, designated strain SM1970 T , was isolated from a seawater sample collected from the Mariana Trench. Strain SM1970 T grew at 15-37 o C and with 1–5% (w/v) NaCl. It hydrolyzed colloidal chitin, agar and casein but did not reduce nitrate to nitrite. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SM1970 T formed a distinct lineage close to the genus Catenovulum within the family Alteromonadaceae , sharing the highest sequence similarity (93.6%) with type strain of Catenovulum maritimum but < 93.0% sequence similarity with those of other known species in the class Gammaproteobacteria. The major fatty acids of strain SM1970 T were summed feature 3 (C 16: 1 ω 7 c and/or C 16: 1 ω 6 c ), C 16: 0 and summed feature 8 (C 18: 1 ω 7 c and/or C 18: 1 ω 6 c ). The major polar lipids of the strain included phosphatidylethanolamine and phosphatidylglycerol and its main respiratory quinone was ubiquinone 8. The draft genome of strain SM1970 T consisted of 77 scaffolds and was 4,172,146 bp in length, containing a complete set of genes for chitin degradation. The average amino acid identity (AAI) values between SM1970 T and type strains of known Catenovulum species were 56.6–57.1% while the percentage of conserved proteins (POCP) values between them were 28.5–31.5%. The genomic DNA G + C content of strain SM1970 T was 40.1 mol%. On the basis of the polyphasic analysis, strain SM1970 T is considered to represent a novel species in a novel genus of the family Alteromonadaceae , for which the name Marinifaba aquimaris is proposed with the type strain being SM1970 T (= MCCC 1K04323 T = KCTC 72844 T ).