ALCOHOLIC FERMENTATION. 205 



IWANOFF l the phosphoric acid combination is a triose phosphate which 

 is fermented, with the formation of carbon dioxide, alcohol and phos- 

 phoric acid, by the dead and not by the living yeast. On the contrary 

 LEBEDEW finds the same formula as YOUNG 2 for the phosphoric acid 

 ester. IWANOFF as well as EULER and their collaborators admit that 

 the formation of phosphoric acid esters is brought about by a special 

 enzyme. 3 According to IWANOFF and to LEBEDEW the sugar is first 

 fermented after it has combined with the phosphoric acid. It seems, 

 according to all evidence, that phosphoric acid esters of carbohydrates 

 are formed and that these are in some way of importance for the accom- 

 plishment of the fermentation. It is not probable that in the fermenta- 

 tion the hexose does not directly break into alcohol and C02. It is 

 generally admitted that the process takes place through intermediary 

 steps. Lactic acid is considered as one of these, although in fact, this 

 acid is not fermented with the formation of alcohol. Recently BUCHNER 

 and MEISSENHEIMER 4 have proposed dioxyacetone (HOCEb.CO.CH^OH) 

 as a probable intermediary step. They found that dioxyacetone was 

 very readily fermented by press-juice in the presence of common salt 

 and indeed with the formation of alcohol and carbon dioxide. This has 

 been substantiated by LEBEDEW. S HARDEN and YOUNG disputed the 

 possibility that dioxyacetone is an intermediary step in the alcoholic 

 fermentation of sugar because it is more slowly fermented than the 

 sugars. 6 



Besides ethyl alcohol and carbon dioxide there are formed in the fer- 

 mentation of sugar, although in small amounts, several higher alcohols 

 which form the so-called fusel oil. The most important constituents 

 of fusel oil are isoamylalcohol, d-amylalcohol, isobutylalcohol and normal 

 propylalcohol in varying proportions. The formation of fusel oil was 

 ascribed for a long time to the action of bacteria until F. EHRLICH 7 

 found that the higher alcohols could be produced from certain amino- 

 acids by the living activity of yeast. From an amino-acid probably 

 the corresponding oxyacid is formed first by the splitting off of ammonia, 



1 Centralbl. f. Bakfc. 24, 1 (1909). 



2 Bioch. Zeitschr. 36, 248 (1911). 



3 Euler and Kullberg, Zeitschr. f. physiol. Chem., 74, 15 (1911); 80, 175 (1912); 

 Bioch. Zeitschr., 37, 133 (1911). 



4 In reference to the intermediary products in alcoholic fermentation see Buchner 

 and Meissenheimer, Jter. d. d. chem. Gesellsch., 43, 1773 (1910) which also contains 

 the literature. 



5 Compt. Rend., 153, 136 (1911). 



s Bioch. Zeitschr., 40, 458 (1912). 



7 Zeitschr. f. Ver. d. d. Zuckerind, 55, 539 (1905) also Ber. d. d. chem. Gesellsch, 

 40, 1027, 2538 (1907); Bioch. Zeitschr. 1, 8 (1906); 8, 438 (1908); 18, 391 (1909). 



