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Desulfobulbus aggregans sp. nov., a Novel Sulfate Reducing Bacterium Isolated from Marine Sediment from the Gulf of Gabes

Kharrat, Hanen, Karray, Fatma, Bartoli, Manon, Ben Hnia, Wajdi, Mhiri, Najla, Fardeau, Marie-Laure, Bennour, Feten, Kamoun, Lotfi, Alazard, Didier, Sayadi, Sami
Current microbiology 2017 v.74 no.4 pp. 449-454
1-propanol, DNA, Desulfobulbus, butanol, carbon, ethanol, formates, glucose, glycerol, hydrogen sulfide, lactic acid, marine sediments, new species, nucleotide sequences, pH, phenotype, phosphogypsum, phylogeny, propionic acid, pyruvic acid, ribosomal RNA, salinity, sequence homology, sodium chloride, sulfates, sulfites, temperature, thiosulfates, Tunisia
Three sulfate-reducing bacterial strains designated SM40ᵀ, SM41, and SM43 were isolated from marine sediment in the region of Skhira located in the Gulf of Gabes (Tunisia). These strains grew in anaerobic media with phosphogypsum as a sulfate source and sodium lactate as an electron and carbon source. One of them, strain SM40ᵀ, was characterized by phenotypic and phylogenetic methods. Cells were ovoid, Gram-stain-negative and non-motile. The temperature limits for growth were 10 and 55 °C with an optimum at 35 °C and the pH range was 6.5–8.1 with an optimum at pH 7.5. Growth was observed at salinities ranging from 10 to 80 g NaCl l⁻¹ with an optimum at 30 g NaCl l⁻¹. Strain SM40ᵀ was able to utilize butanol, ethanol, formate, L-glucose, glycerol, lactate, propanol, propionate, and pyruvate as electron donors for the reduction of sulfate, sulfite, or thiosulfate to H₂S. Without electron acceptors, strain SM40ᵀ fermented butanol and pyruvate. The DNA G+C content of strain SM40ᵀ was 52.6 mol %. Phylogenetic analysis based on the 16S rRNA gene sequence of the isolate revealed that strain SM40ᵀ was closely related to the species in the genus Desulfobulbus of the family Desulfobulbaceae. The sequence similarity between strain SM40 and Desulfobulbus marinus was 95.4%. The phylogenetic analysis, DNA G+C content, and differences in substrate utilization suggested that strain SM40 represents a new species of the genus Desulfobulbus, D. aggregans sp. nov. The type strain is strain SM40ᵀ (=DSM 28693ᵀ = JCM 19994ᵀ).