Page:Bergey's manual of determinative bacteriology.djvu/105

 Molisch, Cent. f. Bakt., II Abt., 33, 1912, 55; Vislouch, Jour, de Microbiologie (Russian), 1, 1914, 50.)

bi.punc.ta′ta. L. bis twice; L. noun punctum a point, spot; M.L. adj. bipunctatus two-spotted.

Small, slightly bent sulfur spirilla, markedly pointed at the ends; 6.6 to 14 microns long, 1.7 to 2.4 microns wide (in the center of the cell). Both ends are more or less filled with large volutin (metachromatic) granules. Several minute granules of sulfur are present in the clear center and sometimes at the ends. Old cells possess one flagellum at each end; young cells have a flagellum at one end.

Habitat: Sea and salt waters.

(Beijerinck, Cent. f. Bakt., II Abt., 11, 1904, 593; not Thiobacillus Ellis, Sulphur Bacteria, London, 1932, 130; Sulfomonas Orla-Jensen, Cent. f. Bakt., II Abt., 22, 1909, 314.)

Thi.o.ba.cil′lus. Gr. noun thium sulfur; L. noun bacillus a small rod; M.L. mas. n. Thiobacillus a sulfur rodlet.

Small, Gram-negative, rod-shaped cells. Non-motile or motile, usually by means of a single polar flagellum. Energy derived from the oxidation of incompletely oxidized sulfur compounds, principally from elemental sulfur and thiosulfate but in some cases also from sulfide, sulfite and polythionates. The principal product of oxidation is sulfate, but sulfur is sometimes formed. Grow under acid or alkaline conditions and derive carbon from carbon dioxide or from bicarbonates in solution; some are obligate and some facultatively autotrophic. Some species are anaerobic in the presence of nitrate. Found in soil, mine wastewaters, sewage, effluents and related sources.

The type species of this genus is strictly autotrophic as are the majority of the species in the genus. It has been suggested that Thiobacillus should be restricted to these autotrophic species and that the facultatively autotrophic species be placed in the genus Pseudomonas. Some heterotrophic species now placed in Pseudomonas are known to have the ability to oxidize thiosulfates (Starkey, Soil Sci., 39, 1935, 325).

The type species is Thiobacillus thioparus Beijerinck.

I. Thiosulfate oxidized with increased acidity.


 * A. Tetrathionate not formed as an intermediate product.


 * 1. Strictly autotrophic.


 * a. Does not oxidize ferrous salts.


 * aa. Oxidizes ferrous salts.


 * 2. Facultatively autotrophic.


 * a. Aerobic.


 * b. Does not oxidize free sulfur.


 * bb. Oxidizes free sulfur to sulfate.


 * aa. Facultatively anaerobic in presence of nitrate.


 * B. Tetrathionate formed as intermediate product.


 * 1. Final pH, 3.0.