Page:Bergey's manual of determinative bacteriology.djvu/208

 2. Acetobacter xylinum (Brown, Holland, 1920. (Bacterium xylinum Brown, Jour. Chem. Soc, London, 49, 1886, 439; Holland, Jour. Bact., 5, 1920, 216.)

xy'li.num. Gr. adj. xylinus of cotton; L. neut.n. xylinum cotton.

Rods, about 2 microns long, occurring singly and in chains. The cells have a slimy envelope which gives the cellulose reaction.

A zoogloeal film forms on all liquid media in which growth occurs; the nature of the medium influences the thickness of the film which may vary from 2 to 250 millimeters. The film becomes cartilagenous and falls to the bottom if disturbed.

X-ray pattern studies made by Khouvine, Champetier and Sutra (Compt. rend. Acad. Sci. Paris, 194, 1932, 208) and by Barsha and Hibbert (Can. Jour. Research, 10, 1934, 170) have shown that the cellulose contained in the membranes formed by Acetobacter xylinum is identical with cotton cellulose.

Acid from glucose, ethanol, propanol and glycol. No acid from arabinose, fructose, galactose, maltose, lactose, raffinose, dextrin, starch, methanol, isopropanol, butanol, isobutanol, pentanol, mannitol or acetaldehyde (Henneberg, Die deutsch. Essigind., 2, 1898, 147).

Distinctive character: The production of thick, leathery, zoogloeal, cellulosic membranes on the surface of liquids.

Optimum temperature, 28° C.

Habitat: Vinegar, souring fruits, vegetables and beverages.

3. Acetobacter rancens Beijerinck, 1898. (Bacterium rancens Beijerinck, Cent. f. Bakt., II Abt., 4, 1898, 211; Beijerinck, in Krai's Sammlung v. Mikroorg., Prague, 1898, 4.)

ran'cens. L. part. adj. rancens putrid, stinking.

The following description is taken in part from a study of a culture of Acetobacter rancens received from Kluyver by Vaughn; also see Frateur (La Cellule, 53, 1950, 339).

Rods with the usual morphological appearance of cultures of acetic-acid bacteria. Gram-negative. Molitility variable. Motile cells possess a single polar fiagellum (Vaughn, Jour. Bact., 46, 1943, 394). Involution forms commonly appear as filaments and enlarged cells.

Wort agar slant: Growth abundant, butyrous, pale-buff in color in one week.

Yeast infusion, glucose, calcium carbonate slant: Growth abundant, butyrous and cream-colored in one week.

With petri-dish cultures, well isolated colonies are large, smooth and butyrous on the above-mentioned media.

Broth cultures containing peptone or yeast infusion form a mucilaginous, slimy pellicle. Beijerinck (op. cit., 4, 1898, 211) called this polysaccharide pellicle cellulose-like and intimated that the mucilaginous material in the pellicle was somewhat different from that produced by Acetobacter xylinum. The pellicle material stained blue when treated with iodine and hydroiodic acid.

Minimum nutritional requirements: Pantothenic acid, nicotinic acid, p-aminobenzoic acid, thiamine, valine, alanine, isoleucine, histidine, cystine, proline, aspartic or glutamic acid, mineral salts and an oxidizable substrate such as alcohol, glucose, etc. (Foda and Vaughn, Jour. Bact., 65, 1953, 79).

Acid from glucose, ethanol, propanol, butanol, glycol, adonitol, mannitol and sorbitol. No acid from numerous other compounds tested.

Distinctive character: Production of a thin, mucilaginous, slimy, polysaccharide membrane on the surface of liquids as compared with the thick, true cellulose membrane of Acetobacter xylinum grown under the same conditions. Beijerinck (op. cit., 4, 1898, 211) reported the production of a cellulose-like membrane with some cultures of Acetobacter rancens.

Source: Isolated from shavings in the quick-vinegar process.

Habitat: Found in fermented grain mash, malt beverages, mother of vinegar, and souring fruits.

Beijerinck (Cent. f. Bakt., II Abt., 4, 1898, 211) thought that the next two species were hardly more than varieties of Acetobacter rancens; also see Frateur (La Cellule, 53, 1950, 339).