Researchers proposed the establishment of a new bacterial genus, Acidomonas, to accommodate Acetobacter methanolicus and related strains. These gram-negative, nonsporeforming, nonmotile rods are acidophilic and facultatively methylotrophic, growing at pH 2.0 to 5.5—a unique characteristic among methanol-utilizing bacteria. The organisms have DNA with 63-65 mol% guanine plus cytosine content. Five strains, including the type strain Acidomonas methanolica TK 0705, were analyzed for phenotypic and chemotaxonomic properties. The bacteria can utilize methanol, ethanol, acetic acid, glucose, glycerol, and pectin as carbon sources. They were distinguished from related genera (Acetobacter, Gluconobacter, Acidiphilium, and Thiobacillus) through DNA-DNA hybridization studies and analysis of cellular fatty acids, hydroxy fatty acids, and ubiquinone systems. The authors designated Acidomonas methanolica as the type species of the new genus, with strain TK 0705 (also IMET 10945) as the reference strain.

Key findings

• A new genus Acidomonas was established with Acidomonas methanolica as the type species, separating methanol-utilizing acidophilic bacteria from the genus Acetobacter
• Acidomonas methanolica strains are unique among methanol-utilizing bacteria in growing at pH 2.0-5.5, with DNA composition of 63-65 mol% G+C
• DNA-DNA hybridization studies clearly separated the five Acidomonas strains from related genera including Acetobacter, Gluconobacter, Acidiphilium, and Thiobacillus
• The organisms are gram-negative, nonmotile rods with facultative methylotrophy and can utilize methanol, ethanol, acetic acid, glucose, glycerol, and pectin as sole carbon sources