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 degrees 40' S 68 degrees 25' E). The isolate grew optimally at 22 degrees C and minimum and maximum temperature of growth were 4 and 37 degrees 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(18:1)omega7c (9.0%) and C(18:1)omega9c (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.