A mesophilic, facultatively anaerobic, marine bacterium, designated strain FG1T, was isolated from a seagrass bed sediment sample collected from Nanwan Bay, Kenting National Park, Taiwan. Cells grown in broth cultures were motile, Gram-negative rods; motility was normally achieved by two sheathed flagella at one pole of the cell. Strain FG1T required Na+ for growth, and exhibited optimal growth at 30-35 degrees C, pH 6-7 and about 4% NaCl. It grew anaerobically by fermenting glucose and other carbohydrates with production of various organic acids, including acetate, lactate, formate, malate, oxaloacetate, propionate, pyruvate and succinate, and the gases CO2 and H2. The strain did not require either vitamins or other organic growth factors for growth. Its DNA G+C content was 45.9 mol%. It contained C12:0 as the most abundant cellular fatty acid. Characterization data, together with the results of a 16S rDNA-based phylogenetic analysis, indicate that strain FG1T represents a new species of the genus Vibrio. Thus, the name Vibrio aerogenes sp. nov. is proposed for this new bacterium. The type strain is FG1T (= ATCC 700797T = CCRC 17041T).