Strain AAFu3 T (l DSM 11263 T l ATCC BAA-311 T ), a Gram-negative, nonsporulating bacterium, was isolated from a methanogenic mixed culture growing with acetone, in which acetate was the major intermediate. The cells of strain AAFu3 T were slender spirilla, usually of less than one turn, and were motile by means of a single polar flagellum. The cells contained c-type cytochromes and the GMC content of the genomic DNA was 502 mol %. Sulfur, nitrate, fumarate, DMSO and oxygen

more »

... were used as electron acceptors, but sulfate, sulfite, thiosulfate and ferric iron were not. Sulfide, hydrogen, formate and acetate acted as electron donors for respiratory growth, while fumarate, maleate and L-malate supported fermentative growth. Neither fermentative nor respiratory growth was supported by carbohydrates, fatty acids more than two carbons long, alcohols or amino acids. The strain was a mesophile. Comparative sequence analysis of the 16S rRNA gene and comparison of phenotypic characteristics showed that strain AAFu3 T is closely related to Geovibrio ferrireducens, within the phylum Deferribacteres. Strain AAFu3 T was designated as the type strain of a new species, for which the name Geovibrio thiophilus is proposed.