Glycocaulis alkaliphilus sp. nov., a dimorphic prosthecate bacterium isolated from crude oil.

A bacterial strain designated 6B-8(T) was isolated from crude oil from Daqing oilfield, China. Cells of strain 6B-8(T) were Gram-negative, aerobic, dimorphic and reproduced by means of binary fission. Strain 6B-8(T) could grow at 20-37 °C, pH 8-10 and 1-5 % (w/v) NaCl. Its genomic DNA G+C content was 62.0 mol%. The predominant cellular fatty acids were C18 : 1ω7c, C17 : 0, C18 : 0 and 11-methyl C18 : 1ω7c and the main hydroxy fatty acids were C12 : 0 3-OH and C12 : 1 3-OH when grown on marine agar 2216. The major quinone was Q-10 and the major polar lipids were three unidentified glycolipids. Phylogenetic analysis revealed that strain 6B-8(T) was a member of the family Hyphomonadaceae, sharing 99.6 and 99.4 % 16S rRNA gene sequence similarity with Glycocaulis abyssi LMG 27140(T) and Glycocaulis albus SLG210-30A1(T), respectively, and less than 94.4 % similarity with the type strains of other members of the family Hyphomonadaceae. However, the DNA-DNA relatedness between strain 6B-8(T) and related strains G. abyssi LMG 27140(T) and G. albus SLG210-30A1(T) was 36±5 and 42±5 %, respectively. In addition, several phenotypic and genotypic features allowed differentiation of strain 6B-8(T) from G. abyssi LMG 27140(T) and G. albus SLG210-30A1(T). Therefore, strain 6B-8(T) represents a novel species of genus Glycocaulis, for which the name Glycocaulis alkaliphilus sp. nov. is proposed. The type strain is 6B-8(T) ( = CGMCC 1.12428(T) = LMG 27410(T)).