Alcanivorax borkumensis gen. nov., sp. nov., a new, hydrocarbon-degrading and surfactant-producing marine bacterium

During screening for biosurfactant-producing, n-alkane-degrading marine bacteria, six heterotrophic bacterial strains were isolated from enriched mixed cultures, obtained from sea water/sediment samples collected near the Isle of Borkum (North Sea), using Mihagol-S (C14,15-n-alkanes) as principal carbon source. These Gram-negative, aerobic, rod-shaped bacteria use a limited number of organic compounds, including aliphatic hydrocarbons, volatile fatty acids, and pyruvate and its methyl ether. During cultivation on n-alkanes as sole source of carbon and energy, all strains produced both extracellular and cell-bound surface-active glucose lipids which reduced the surface tension of water from 72 to 29 mNm-1(16). This novel class of glycolipids was found to be produced only by these strains. The 16S rRNA gene sequence analysis showed that these strains are all members of the γ-subclass of the Proteobacteria. Their phospholipid ester-linked fatty acid composition was shown to be similar to that of members of the genus Halomonas, although they did not demonstrate a close phylogenetic relationship to any previously described species. On the basis of the information summarized above, a new genus and species, Alcanivorax borkumensis, is described to include these bacteria. Strain SK2Tis the type strain of A. borkumensis.