Marinobacter maritimus sp. nov., a psychrotolerant strain isolated from sea water off the subantarctic Kerguelen islands

Abstract

A psychrotolerant, Gram-negative, motile bacterium, designated CK 47^T, was isolated from sea water off the subantarctic Kerguelen islands (50° 40' S 68° 25' E). The isolate grew optimally at 22°C and minimum and maximum temperature of growth were 4 and 37°C, respectively. It required Na⁺ for growth and exhibited optimum growth at pH 8·5 and 4% NaCl. It utilized hexane, heptane and petroleum ether as sole sources of carbon. Strain CK 47^T had Q9 as the major respiratory quinone and C_16:0 (21·7%), C_17:0 (21·3%), C_18:0 (5·7%), C_18:1ω7c (9·0%) and C_18:1ω9c (31·4%) as predominant fatty acids. The G+C content of the DNA was 58 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that CK 47^T formed a coherent cluster within the genus Marinobacter. It exhibited highest 16S rRNA gene sequence similarity of 96·8% with Marinobacter lipolyticus. However, the level of DNA-DNA relatedness between strain CK47^T and M. lipolyticus was only 55%. On the basis of phenotypic characteristics, and phylogenetic and genotypic distinctiveness, strain CK 47^T is considered to represent a novel species of the genus Marinobacter. The name Marinobacter maritimus sp. nov. is proposed, with CK 47^T (=JCM 12521^T=MTCC 6519^T) as the type strain.