PRODUCTS FROM NITROGENOUS COMPOUNDS 87 



alcohol (C 3 H 7 OH), and acetic acid (CH 3 COOH) from ethyl alcohol 

 (C 2 H 5 OH). 



Other Acid Fermentation. In addition to the acids described 

 many others have been identified among the products of carbohy- 

 drate fermentation. Many molds, especially, possess the power of 

 fermenting dextrose with the formation of citric acid, the general 



reaction being as f ollows : 



CH 2 COOH 



/ 



2C 6 Hi2O 6 + 2O 2 = 2HOC COOH + 2H 2 O 



\ 



CH 2 COOH 

 Dextrose. Citric acid. 



Patents have been taken out on this method and attempts made 

 to produce citric acid on a commercial scale, but so far without any 

 great success. 



Oxalic acid is also produced by certain molds in sugar solutions 

 and w^here care has been taken to neutralize the acid so formed 

 one-half the calculated theoretical yield has been obtained from 

 cane sugar. Formic (H COOH) and valeric acids (C 4 H 9 COOH) 

 are also produced by some microorganisms. 



Oxidation of Organic Acids. The organic acids formed in the 

 various processes of carbohydrate fermentation are often further 

 oxidized by bacteria, yeasts, or molds to simpler products. Ordi- 

 narily the process consists of a complete oxidation. This may be the 

 case in sauerkraut, ensilage, pickles, etc. Thus O'idin m ludis destroys 

 the lactic acid of sour milk with the formation of carbon dioxid 

 and water. 



+ 3O : = 3CO 2 + 3H 2 O. 



At times the spoiling of pickles is due to the oxidation of the acetic 

 acid by yeasts which grow 7 in a thin white scum over the surface. 



Fats. A. comparatively few microorganisms attack fat. When 

 they do the decomposition of the fat is comparatively simple. One 

 molecule of the neutral fat is split \vith the formation of one mole- 

 cule of glycerin and three of fatty acids. 



H 2 COOC CisHai H 2 COH 



HCOOC CisHai + 3H 2 O H COH + 3Ci 5 H 31 COOH 



HzCOOC CisHsi H 2 COH 



Neutral fat. Glycerin. Fatty acid. 



The glycerin is readily used by the microorganism, whereas the 

 fatty acids are but very slowly oxidized and that by only a few r 

 species. 



Products from Nitrogenous Compounds. Proteins are complex 

 organic substances composed of carbon, hydrogen, oxygen, nitrogen, 



