Desulfoglaeba alkanexedens gen. nov., sp. nov., an n-alkane-degrading, sulfate-reducing bacterium

Abstract

Two novel sulfate-reducing bacteria, strains ALDCTand Lake, which were able to oxidize n-alkanes, were isolated from a naval oily wastewater-storage facility (VA, USA) and from oilfield production water (OK, USA), respectively. The type strain (ALDCT) had a narrow substrate specificity and could grow only with n-alkanes (from C6to C12), pyruvate, butyrate, hexanoic acid and 4-methyloctanoic acid. Cells of strain ALDCTstained Gram-negative and were slightly curved, short rods with oval ends (2.5–3.0×1.0–1.4 μm), often occurring in pairs. Cells tended to form aggregates or large clusters and were non-motile and did not form endospores. Optimum growth occurred between 31 and 37 °C and at pH 6.5–7.2. NaCl was not required for growth, but salt concentrations up to 55 g l−1could be tolerated. The DNA G+C content was 53.6 mol%. Phylogenetic analysis of the 16S rRNA genes revealed that strains ALDCTand Lake were closely related, but not identical (99.9 % similarity). The two strains were not closely related to other known alkane-degrading, sulfate-reducing bacteria or to other genera of theDeltaproteobacteria. Therefore, it is proposed that strain ALDCT(=JCM 13588T=ATCC BAA-1302T) represents the type strain of a novel species and genus, with the nameDesulfoglaeba alkanexedensgen. nov., sp. nov.