A novel aerobic, Gram-negative bacterium, named 13IX/A01/164^T, was isolated from surface waters in the coastal north-western Mediterranean Sea. Cells were motile, straight rods, 2.5 μm long and 0.2 μm wide, and formed orange colonies on marine agar medium. The G+C content of the genomic DNA of strain 13IX/A01/164^T was 42 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed the strain in the phylum Bacteroidetes within the family Crenotrichaceae. On the basis of 16S rRNA gene sequence comparison and physiological and biochemical characteristics, this isolate represents a novel species of a new genus, for which the name Balneola vulgaris gen. nov., sp. nov. is proposed. The type strain of Balneola vulgaris is 13IX/A01/164^T (=DSM 17893^T=CIP 109092^T=OOB 256^T).

A novel aerobic, Gram-negative bacterium, designated 3X/A02/235^T, was isolated from the surface of coastal waters in the north-western Mediterranean Sea. Cells were motile, straight rods, 1.6 μm long and 0.5 μm wide, and formed cream colonies on marine agar medium. The G+C content of the genomic DNA was 61 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed the strain in the class Gammaproteobacteria and within the family Alteromonadaceae. On the basis of 16S rRNA gene sequence comparisons and physiological and biochemical characteristics, this isolate represents a novel species of a novel genus, for which the name Haliea salexigens gen. nov., sp. nov. is proposed. The type strain of Haliea salexigens is 3X/A02/235^T (=DSM 19537^T =CIP 109602^T =MOLA 286^T).

A novel anaerobic, Gram-positive, sporulating and strictly chemoorganoheterotrophic bacterium, designated strain DV1184^T, was isolated from a deep-sea hydrothermal vent sample from the Mid-Atlantic Ridge. The cells were short, straight rods (4 μm long and 0·8 μm wide) and were motile with peritrichous flagella. They grew between 35 and 55 °C (optimum, 45 °C), between pH 5·0 and 8·0 (optimum, 6·0) and at 20–60 g sea salts l⁻¹(optimum sea salts concentration, 30 g l⁻¹). Strain DV1184^Twas able to ferment yeast extract, tryptone, peptone, glucose, sucrose, maltose and pyruvate. The main fermentation products from glucose were (in decreasing order) formate, acetate and ethanol. The genomic DNA G+C content was 29 mol%. Phylogenetic analysis of the 16S rRNA gene located the strain within cluster XI of the lineage that encompasses the genusClostridiumand related genera in the bacterial domain. On the basis of 16S rDNA sequence comparison and physiological and biochemical characteristics, it is proposed that the isolate should be described as a novel species,Tepidibacter formicigenessp. nov. The type strain is DV1184^T(=CIP 107893^T=DSM 15518^T).

Two novel Gram-negative bacteria, designated strains DR41_21T and DR41_18T, were isolated from coastal, surface waters of the north-western Mediterranean Sea. The cells were motile, pleomorphic rods, 2.9 μm long and 0.9 μm wide and formed cream colonies on marine agar medium. The G+C content of the genomic DNA was 60 mol%. Phylogenetic analysis of 16S rRNA gene sequences positioned the isolates in the class Alphaproteobacteria within the family Rhodospirillaceae. The 16S rRNA gene sequence similarity of the two strains was 98.8 % but DNA–DNA hybridization indicated only 55 % relatedness. Strain DR41_21T was able to denitrify and possessed nirK and nosZ genes, unlike strain DR41_18T, which possessed only nirK. These isolates represent two novel species of a new genus, Nisaea gen. nov., for which the names Nisaea denitrificans sp. nov. and Nisaea nitritireducens sp. nov. are proposed. The type strain of Nisaea denitrificans is DR41_21T (=DSM 18348T=CIP 109265T=OOB 129T) and the type strain of Nisaea nitritireducens is DR41_18T (=DSM 19540T=CIP 109601T=OOB 128T).

A novel anaerobic, thermophilic and heterotrophic bacterium, designated strain DV1140^T, was isolated from a deep-sea hydrothermal vent sample from the Mid-Atlantic Ridge. The cells were non-motile straight rods, 1·8 μm long and 0·4 μm wide, surrounded by an outer sheath-like structure (toga). They grew at 45–80 °C (optimum 65 °C), pH 5·0–9·0 (optimum pH 6·0) and at sea salt concentrations of 20–60 g l⁻¹(optimum 30 g l⁻¹). Strain DV1140^Twas able to ferment yeast extract, peptone, brain heart infusion, gelatin, starch, galactose, arabinose, glucose, trehalose and cellobiose. The fermentation products identified on glucose in the presence of yeast extract and peptone were acetate, isovalerate and hydrogen. The G+C content of the genomic DNA was 33 mol%. Phylogenetic analysis of the 16S rRNA gene sequence (GenBank accession number AJ577471) located the strain within the genusThermosiphoin the bacterial domain. On the basis of 16S rRNA gene sequence comparisons, and physiological and biochemical characteristics, the isolate represents a novel species, for which the nameThermosipho atlanticussp. nov. is proposed. The type strain is DV1140^T(=CIP 108053^T=DSM 15807^T).