Oleiphilaceae fam. nov., to include Oleiphilus messinensis gen. nov., sp. nov., a novel marine bacterium that obligately utilizes hydrocarbons

P. N. Golyshin, T. N. Chernikova, W. R. Abraham, H. Lunsdorf, K. N. Timmis and M. M. Yakimov Division of Microbiology, GBF--German Research Centre for Biotechnology, Mascheroder Weg 1, 38124 Braunschweig, Germany A bacterial isolate, ME102(T), was obtained from an n-hexadecane enrichment culture of seawater/sediment samples collected in the harbour of Messina (Italy). This Gram-negative, aerobic, motile, rod-shaped bacterium used a narrow spectrum of organic compounds, including aliphatic hydrocarbons, alkanoates and alkanoles, as carbon and energy sources. None of the sugars, organic acids or amino acids tested was used. During cultivation on n-alkanes as the sole source of carbon and energy, the cells formed a biofilm on the surface of the alkane droplets. Large-scale (sometimes > 50% of the cell mass) intracellular accumulation of alkanoates occurred in cells adsorbed on the alkane surface and under nitrogen-limiting conditions. 16S rRNA gene sequence analysis showed that this isolate represents a distinct lineage in the gamma-Proteobacteria and has about 91% sequence identity to members of Marinobacter and Alcanivorax, the closest genera. Four different types of polar lipid could be detected, phosphatidyl glycerol, phosphatidyl ethylamine, phosphatidyl dimethylethylamine and lipids belonging to an unknown type of phospholipid (m/z between 861 and 879). The principal fatty acids in the polar lipid fatty acid profile were 16:0 and 16:1. The putative gene encoding the key enzyme of alkane catabolism, alkane hydroxylase (AlkB), has been cloned. The protein sequence of the putative AlkB of the isolate ME102(T) was related to the AlkB of Pseudomonas oleovorans and Alcanivorax borkumensis, showing about 60% sequence identity. On the basis of physiological studies and taking into account the distant phylogenetic position of isolate ME102(T) relative to previously described organisms, a novel genus and species is proposed, Oleiphilus messinensis gen. nov., sp. nov., within a new family, Oleiphilaceae fam. nov. Strain ME102(T) (=DSM 13489(T)=LMG 20357(T)) is the type and only strain of O. messinensis.