Desulfovibrio alaskensis sp. nov., a sulphate-reducing bacterium from a soured oil reservoir

1 School of Pharmacy and Biomedical Sciences, University of Portsmouth, St Michael's Building, White Swan Rd, Portsmouth PO1 2DT, UK 2 Max-Planck-Institut für marine Mikrobiologie, Celsiusstr. 1, D-28359 Bremen, Germany 3 IWW, Rheinisch-Westfälisches Institut für Wasserchemie und Wassertechnologie, Moritzstr. 26, 45476 Mülheim/Ruhr, Germany 4 IFREMER, Centre de Brest, DRV/VP/BMH, BP 70, 29280 Plouzané, France Correspondence Iwona B. Beech Iwona.Beech{at}port.ac.uk A novel sulphate-reducing bacterium (Al1 T ) was recovered from a soured oil well in Purdu Bay, Alaska. Light and atomic force microscopy observations revealed that cells were Gram-negative, vibrio-shaped and motile by means of a single polar flagellum. The carbon and energy sources used by the isolate and the salinity, temperature and pH ranges facilitating its growth proved to be typical of a partial lactate-oxidizing, moderately halophilic, mesophilic, sulphate-reducing bacterium. Analysis of the fatty acid profile revealed that C 18 : 0 , isoC 15 : 0 and isoC 17 : 1 7 c were the predominant species. Fatty acid profile and complete 16S rRNA gene sequencing demonstrated the similarity between strain Al1 T and members of the genus Desulfovibrio . The position of strain Al1 T within the phylogenetic tree indicated that it clustered closely with Desulfovibrio vietnamensis DSM 10520 T (98·9 % sequence similarity), a strain recovered from a similar habitat. However, whole-cell protein profiles, Fourier-transform infrared studies and DNA–DNA hybridization demonstrated that, in spite of the high level of 16S rRNA gene sequence similarity, there is sufficient dissimilarity at the DNA sequence level between D. vietnamensis DSM 10520 T and strain Al1 T (10·2 % similarity) to propose that strain Al1 T belongs to a separate species within the genus Desulfovibrio . Based on the results obtained, the name Desulfovibrio alaskensis sp. nov. is therefore proposed, with Al1 T (=NCIMB 13491 T =DSM 16109 T ) as the type strain. Abbreviations: AFM, atomic force microscopy; FT-IR spectroscopy, Fourier-transform infrared spectroscopy; SRB, sulphate-reducing bacterium Published online ahead of print on 26 March 2004 as DOI 10.1099/ijs.0.63118-0. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain Al1 T is Y11984 . The fatty acid profile and an AFM image of strain Al1 T , FT-IR spectra of various SRB and a dendrogram based on these spectra are available as supplementary material in IJSEM Onl