Actibacterium atlanticum sp. nov., isolated from surface seawater of the Atlantic Ocean.

Abstract

A taxonomic study was carried out on strain 22II-S11-z10(T), which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-stain negative, oxidase and catalase positive, oval- to rod-shaped and non-motile. Growth was observed at salinities of 0.5-9% and at temperatures of 10-41°C. The isolate can reduce nitrate to nitrite, degrade gelatin and aesculin, but can not degrade Tween 80. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 22II-S11-z10(T) belongs to the genus Actibacterium, with the highest sequence similarity to the type strain Actibacterium mucosum CECT 7668(T) (97.3%). The DNA-DNA hybridization estimate value between strain 22II-S11-z10(T) and A. mucosum CECT 7668(T) was 19.30±2.29%. The principal fatty acids were identified as Summed Feature 8 (C18:1 ω7c/ω6c as defined by the MIDI system, 75.2%) and Summed Feature 3 (C16:1 ω7c/ω6c, 6.9%). The G+C content of the chromosomal DNA was determined to be 59.0mol%. The respiratory quinone was determined to be Q-10 (100%). Phosphatidylglycerol, phosphatidylcholine, two phospholipids, two aminolipids and two lipids were identified in the polar lipids. The combined genotypic and phenotypic data show that strain 22II-S11-z10(T) represents a novel species within the genus Actibacterium, for which the name Actibacterium atlanticum sp. nov. is proposed, with the type strain 22II-S11-z10(T) (=MCCC 1A09298(T)=LMG 27158(T)).