186 



ORDER I. PSEUDOMONADALES 



2. Acetobacter xylinum (Brown, 

 Holland, 1920. {Bacterium xylinum Brown, 

 Jour. Chem. Soc, London, Jfi, 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 

 singl}^ 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, IH, 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, dex- 

 trin, starch, methanol, isopropanol, bu- 

 tanol, isobutanol, pentanol, mannitol or 

 acetaldehyde (Henneberg, Die deutsch. 

 Essigind., 2, 1898, 147). 



Distinctive character: The production of 

 thick, leather}'', zoogloeal, cellulosic mem- 

 branes on the surface of liquids. 



Optimum temperature, 28° C. 



Habitat: Vinegar, souring fruits, vege- 

 tables 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 ap- 

 pearance of cultures of acetic-acid bacteria. 

 Gram-negative. Molitility variable. Motile 

 cells possess a single polar fiagellum 

 (Vaughn, Jour. Bact., ^6, 1943, 394). Involu- 



tion 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 carbon- 

 ate 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 

 xylinutn. The pellicle material stained blue 

 when treated with iodine and hydroiodic 

 acid. 



Minimum nutritional requirements: Pan- 

 tothenic acid, nicotinic acid, p-aminoben- 

 zoic acid, thiamine, valine, alanine, isoleu- 

 cine, histidine, cystine, proline, aspartic or 

 glutamic acid, mineral salts and an oxidiz- 

 able substrate such as alcohol, glucose, etc. 

 (Foda and Vaughn, Jour. Bact., 65, 1953, 

 79). 



Acid from glucose, ethanol, propanol, 

 butanol, glycol, adonitol, mannitol and sor- 

 bitol. No acid from numerous other com- 

 pounds tested. 



Distinctive character: Production of a 

 thin, mucilaginous, slimj^, polysaccharide 

 membrane on the surface of liquids as com- 

 pared with the thick, true cellulose mem- 

 brane 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 Acetobac- 

 ter rancens; also see Frateur (La Cellule, 

 53, 1950, 339). 



