ACID FERMENTATION 147 



unstable, and water is eliminated with formation of the 

 aldehyde group. 



H 



-C-OH = -C + H 2 



Further addition of oxygen gives rise to an acid, thus : 



/0 H 

 + = -C 



If the fermentation is carried still further, hydrocarbons and 

 carbon dioxide (C0 2 ) generally result. E.g., calcium acetate 

 undergoes fermentation with formation of calcium carbonate 

 and marsh gas, thus : 



CH 3 C0 2 



)Ca + H 2 = CaC0 3 + 2CH 4 + C0 2 

 CH 3 CO/ 



Buchner and Meisenheimer and others l have shown by 

 methods similar to those employed in the case of zymase, 

 that the acetic acid and lactic acid fermentations can take 

 place in the absence of living bacteria ; only small quantities 

 of material are however thus transformed compared with the 

 corresponding activity of living organisms. Few, if any, of 

 these reactions are confined to specific bacteria, consequently 

 the oxidation of an alcohol through the intervention of the 

 living organism is a highly complex process, generally resulting 

 in a number of secondary products. The action of an organism, 

 as has been frequently stated, may be broadly described as 

 respiratory and fermentative. It consumes a certain amount 

 of the medium for building up its own structure ; in such a 



1 Fuhrmann, Vorlesungen iiber Bakterienenzyme. 



