Acidiphilium cryptum gen. nov., sp. nov., Heterotrophic Bacterium From Acidic Mineral Environments

Abstract

Acidiphilium gen. nov. is comprised of gram-negative, aerobic, mesophilic, rodshaped bacteria that grow in lean organic media between pH 1.9 and 5.9 but not at pH 6.1, Small amounts of organic substrates are required for growth, but high concentrations inhibit growth, especially the organic digests used in conventional bacteriological media. Sodium acetate is strongly inhibitory at a concentration of 0.01%. Endospores are not formed, and some strains are motile by means of one polar flagellum or two lateral flagella. The guanine-plus-cytosine content of the deoxyribonucleic acid varies between 68 and 70 mol%. Some catalase is formed, but the oxidase reaction is very weak or absent. This genus differs from Pseudomonas, Chromo bacterium, Flauobacterium, and other soil heterotrophs by its requirement for a high concentration of hydrogen ions and its sensitivity to many organic substrates. It differs from Pseudomonas also by its lack of a strong oxidase reaction and especially by its inhibition by acetate. It is easily distinguished from acidophilic thiobacilli by its inability to utilize sulfur and ferrous iron as sources of energy and by the high guanine-plus-cytosine content of deoxyribonucleic acid. The type species is Acidiphilium cryptum, and the type strain of this species is strain Lhet2 (=ATCC 33463).Heterotrophic, mesophilic bacteria with requirements for high acidity have been isolated from allegedly pure cultures of Thiobacillus ferrooxidans (6). These heterotrophs cannot use elemental sulfur or ferrous iron as a source of energy; instead, they utilize organic matter formed by the autotroph T. ferrooxidans (B. W. Jarvis, M.S. thesis, University of Missouri, Columbia, 1979). Heterotrophic bacteria identical to the organisms isolated from T. ferrooxidans cultures were isolated on very dilute Trypticase soy glucose medium at pH 2 directly from acidic coal refuse in Missouri. Bacteria phenotypically similar to these organisms have also been isolated from coal mine water in Pennsylvania (P. L. Wichlacz, M.S. thesis, Pennsylvania State University, University Park, 1980) and from mine drainage elsewhere (10). Other isolations of these bacteria have been described previously (6). In this report I describe these acidophilic heterotrophs in greater detail and propose names for them. MATERIALS AND METHODSMedia. The bacteria were cultivated in a medium containing the following (per liter): (NH4)2S04, 2 g; KC1, 0.1 g; K2HP04, 0.5 g; MgS04.7Hz0, 0.5 g; dehydrated Trypticase soy broth (BBL Microbiology Systems, CockeysviUe, Md.), 0.1 g; and glucose, 1 g. The pH was adjusted to 3 with 1 N HzS04. The glucose was autoclaved separately as a 10% solution, and after cooling a suitable amount was added aseptically to the other autoclaved ingredients (pH 3). This medium without the organic ingredients was designated basal salts medium; when it contained Trypticase soy and glucose, it was designated TS-glucose medium. When solid media were desired, the liquid media were gelled with agar (12 g/liter). The agar and glucose (doubl...

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

“…and coal mine drainage (20,27), and cultures of Thiobacillus ferrooxidans (5)(6)(7)(8)(9)11,18,36,37). Harrison (6) studied systematically acidophilic, mesophilic, heterotrophic bacteria derived directly from coal strip-mine refuse and also as contaminants in cultures of T. ferrooxidans, and proposed the designation of the genus Acidiphilium for these bacteria.…”

“…Harrison (6) studied systematically acidophilic, mesophilic, heterotrophic bacteria derived directly from coal strip-mine refuse and also as contaminants in cultures of T. ferrooxidans, and proposed the designation of the genus Acidiphilium for these bacteria. The genus Acidiphilium now consists of five species, A. cryptum (6), A. organovorum (18), A. angustum (36), A. facilis (36), and A. rubrum (36). Recently, Kishimoto et al (13) have reported Acidobacterium capsulatum, a new acidophilic heterotrophic bacterium isolated from acidic mineral environments.…”

Enhanced Growth of Acidocella facilis and Related Acidophilic Bacteria at High Concentrations of Aluminum.

“…The following strains of acidophilic chemoorganotrophic bacteria were studied: Acidiphilium cryptum ATCC 33463 10) , Acidiphilium organovorum ATCC 43141 23) , Acidiphilium multivorum JCM 8867 39) , Acidocella facilis ATCC 35904 19,40) , Acidocella aminolytica JCM 8796 18,19) , and Acidobacterium capsulatum JCM 7670 17) . The strains with ATCC and JCM numbers were obtained, respectively, from the American Type Culture Collection (Rockville, MD) and Japan Collection of Microorganisms (Wako, Japan).…”

New Strategies for the Selective Isolation of Industrially Important Bacteria

“…Thus, the isolation of Thermosulfobacterium commune (Zeikus et al, 1983) during ecological studies of decomposing algal bacterial mats associated with hot aquatic habitats in Yellowstone National Park led to the discovery of an organism with a highly unusual combination of biochemical, chemical, physiological and structural properties. Other very unusual bacteria isolated from 'exotic' habitats include AcetoanaerobMm (Sleat, Mah and Robinson, 1985), Acidophilus (Harrison, 1981), Dictyoglomus (Saiki et al, 1985), Erythrobacter (Shiba and Simidu, 1982), Methanothermus , Stella (Vasilyeva, 1985), Thermococcus (Zillig et al, 1983) and Thermoproteus . At the other extreme, many newly isolated actinomycete species, such as Dactylosporangiurn roseutn , Microbispora viridis (Miyadoh et al, 1985) and Streptomyces sulfonofaciens (Miyadoh et al, 1983), differ from established species by little other than their ability to produce a novel secondary metabolite.…”