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

Abstract

A novel Gram-negative, rod-shaped, aerobic, oxidase-positive and catalase-negative bacterium, designated strain SM1970T, was isolated from a seawater sample collected from the Mariana Trench. Strain SM1970T grew at 15-37 oC 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 SM1970T formed a distinct lineage close to the genusCatenovulum within the familyAlteromonadaceae, sharing the highest sequence similarity (93.6%) with type strain ofCatenovulum maritimum but < 93.0% sequence similarity with those of other known species in the classGammaproteobacteria. The major fatty acids of strain SM1970T were summed feature 3 (C16: 1ω7c and/or C16: 1ω6c), C16: 0 and summed feature 8 (C18: 1ω7c and/or C18: 1ω6c). The major polar lipids of the strain included phosphatidylethanolamine and phosphatidylglycerol and its main respiratory quinone was ubiquinone 8. The draft genome of strain SM1970T consisted of 77 scaffolds and was 4,172,146bp in length, containing a complete set of genes for chitin degradation. The average amino acid identity (AAI) values between SM1970T and type strains of knownCatenovulum 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 SM1970T was 40.1mol%. On the basis of the polyphasic analysis, strain SM1970T is considered to represent a novel species in a novel genus of the familyAlteromonadaceae, for which the nameMarinifaba aquimaris is proposed with the type strain being SM1970T (= MCCC 1K04323T = KCTC 72844T).