A strictly anaerobic, mesophilic, sulfate-reducing bacterial strain (MSL79
T) isolated from an estuarine sediment in the Sea of Japan of the Japanese islands was characterized phenotypically and phylogenetically. Cells were Gram-negative, motile with a polar flagellum, non-spore-forming, curved rods. Cells had desulfoviridin and
c-type cytochrome. Catalase and oxidase activities were not detected. The optimum NaCl concentration for growth was 2.0% (wt/vol). The optimum temperature was 35°C and the optimum pH was 6.5. Strain MSL79
T utilized H
2, formate, pyruvate, lactate, fumarate, malate, succinate, ethanol, propanol and butanol as electron donors for sulfate reduction. The organic electron donors were incompletely oxidized to mainly acetate. Sulfite and thiosulfate were used as electron acceptors with lactate as an electron donor. Without electron acceptors, pyruvate, fumarate and malate supported the growth. The genomic DNA G + C content was 62.1 mol%. Menaquinone MK-6(H
2) was the major respiratory quinone. Major cellular fatty acids were C
16:0, iso-C
15:0, anteiso-C
15:0, iso-C
17:0, anteiso-C
17:0 and iso-C
17:1ω9. Phylogenetic analysis based on the 16S rRNA gene sequence as well as the α-subunit of dissimilatory sulfite reductase gene sequence assigned the strain to the family
Desulfovibrionaceae within the class
Deltaproteobacteria. The closest validly described species based on the 16S rRNA gene sequences were
Desulfovibrio aespoeensis (sequence similarity; 95.0%) and
Desulfovibrio profundus (94.3%). On the basis of the significant differences in the 16S rRNA gene sequences and the phenotypic characteristics between strain MSL79
T and each of the most closely related species,
Desulfovibrio portus sp. nov. is proposed. The type strain is MSL79
T (= JCM 14722
T= DSM 19338
T).
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