FAMILY PSEUDOMONADACEAE 



183 



Optimum temperature 30°C. Growth 

 occurs between 5° and 42°C. 



Habitat : Vinegar; beer and beer wort. 



3b. Acetobacter kuetzingianum (Han- 

 sen) Bergey et al. (Bacterium kuetzingi- 

 anum Hansen, Compt. rend. d. Trav. d. 

 Lab. d. Carlsberg, 3, 1894. 191; Bergey 

 et al., Manual, 1st cd., 1923, 35.) Xamed 

 for Kuetzing, the German botanist. 



Short, thick rods, occurring singly. 

 Rarely forming chains of notable length. 

 Capsule stained blue with iodine and witli 

 potassium iodide. Xon-motile. 



Double beer gelatin colonies : Small, 

 entire, with vermiform surface. 



Wort gelatin colonies: Small, entire, 

 with surface free of wrinkles. 



Double beer: Forms a rather thick, 

 folded pellicle. Distinguished from A ce- 

 tobacter aceti in showing heavier growth 

 above the surface of the media. 



Acid from glucose, ethyl alcohol, 

 propyl alcohol and glycol. No acid from 

 arabinose, fructose, galactose, sorbose, 

 sucrose, maltose, lactose, raffinose, dex- 

 trin, starch, glycogen, inulin, methyl 

 alcohol, isopropyl alcohol, butyl alcohol, 

 isobutyl alcohol, amyl alcohol, glycerol, 

 erythritol, mannitol, dulcitol and acetal- 

 dehyde (Henneberg, Die deutsch. Essig- 

 ind., £, 1898, 147). 

 Aerobic. 



Optimum temperature 34°C, maximum 

 42°C, minimum 6 to 7°C. 

 Habitat : Beer. Found in double beer. 



gelatin becomes insoluble in boiling water 

 and in trypsin solution. 



Beer- or wort-gelatin plates: Charac- 

 teristic dark brown, wide-spreading, 

 diffuse areas. 



Tap water-agar-glucose-peptone-po- 

 tassium phosphate-iron citrate-chalk 

 medium: In 24 hours at 30°C, black, 

 spreading, diffuse areas. 



Utilizes peptone as a source of nitrogen. 

 Produces the pigment from peptone only 

 if maltose or glucose is present as a 

 source of carbon. When grown in glu- 

 cose-peptone broth with CaCOs at 25° 

 to 30°C, black pigment is produced after 

 several weeks, and the carbonate is 

 changed to calcium gluconate. 



Pigment : The pigment causing the 

 brown coloration is an aromatic substance 

 which is blackened by iron salts. Re- 

 duces alkaline solutions of silver and 

 mercury, blackening them. 



Oxidizes mannitol and sorbitol to fruc- 

 tose and sorbose. Does not attack sucrose 

 and fructose. ]\Iuch gluconic acid is 

 produced. Acid from glucose and mal- 

 tose. Acetic acid produced from alcohol. 

 Distinctive character: The formation 

 of dark brown to black pigment in media 

 containing a suitable substrate; par- 

 ticularly glucose. 

 Source : Isolated from beer. 

 Habitat: Causes light-colored beer to 

 become darker brown. It is a very strong 

 beer-vinegar bacterium. Also found in 

 souring fruits. 



4. Acetobacter melanogenum Bei- 

 jerinck. (Cent. f. Bakt., II Abt., 29, 

 1911, 175.) From Greek melas (mela7i), 

 black; -genes, producing. 



Rods : Xon-motile or motile. Motile 

 cells possess a single polar flagellum 

 (Vaughn. Jour. Bact., 46, 1943, 394). 



Gelatin: Apparent liquefaction prob- 

 ably caused by acid, not an enzyme. 

 When hold on artificial media for some 

 time, the power of liquefying gelatin is 

 lost, probably due to a slower production 

 of acid. Deep brown pigment produced ; 



5. Acetobacter roseum Vaughn. 

 {Bacterium hoshigaki var. rosea Taka- 

 hashi and Asai, Cent. f. Bakt., II Abt., 

 82, 1930, 390; Acetobacter fioshigaki 

 Bergey et al., :Manual, 4th ed., 1934, 39; 

 Vaughn, Wallerstein Lab. Communica- 

 tions, o, Xo. 14, 1942, 20.) From Latin, 

 rasa, rose. 



Rods : 0.7 to 0.9 by 1.5 to 1.8 microns, 

 generally occurring singly, at most in 

 pairs, often in chains. Xon-motile. 

 Pellicle on fluid media yields no starch 

 or cellulose reaction. 



