Acidiphilium multivorum sp. nov., an acidophilic chemoorganotrophic bacterium from pyritic acid mine drainage.

Abstract

Six strains of acidophilic chemoorganotrophic bacteria from acid mine drainage were studied in their taxonomic aspects. They were gram negative, aerobic, mesophilic, oxidase negative, catalase positive, urease positive, nonsporeforming, and rod-shaped. Carotenoid and bacteriochlorophyll a were formed. Two strains had a polar flagellum and other two strains fimbriae. They used a wide variety of organic compounds for growth, but did not use ferrous iron, elemental sulfur, and thiosulfate as the sole energy source. Acetate was inhibitory to growth. Growth was enhanced by adding high concentrations of glucose or complex organic compounds such as trypticase soy (BBL) and yeast extract. Methanol was utilized as the sole source of carbon and energy. The major ubiquinone was Q-10. The major cellular fatty acid was straight-chain unsaturated C18:1 acid. The hydroxy acid was 3-OH C14:0 acid. The DNA base composition was 66.2 to 68.1mol% guanine plus cytosine. The isolates showed relatively low levels of genetic similarity to Acidiphilium cryptum and Acidiphilium organovorum. On the basis of the phenotypic, chemotaxonomic, and genotypic characters, we conclude the isolates as a new species, for which we propose Acidiphilium multivorum sp. nov. The type strain is AIU 301 (JCM 8867).