164 TRANSFORMATION OF MINERAL SUBSTANCES 



3C6H12O6 = 3C4HSO2 + C2H4O2 + 4CO2 + 2H2O +2H2 

 ^acid" "Idd' (anaerobic bacteria) 



3C6H12O6 = 2C4HSO2 + 2C2H4O2 + 4CO2 + 2H2O + 2CH4 



(anaerobic bacteria) 



The decomposition of a carbohydrate may thus lead to the 

 formation of butyric and acetic acids as well as certain gases, 

 largely carbon dioxide and hydrogen or methane, or both together. 

 This was actually demonstrated to take place in the anaerobic 

 decomposition of cellulose. 



In the decomposition of proteins, the amino acids which are 

 formed may decompose further with the liberation of fatty acids: 



R-CH(NH2)C00H + H2O 



Amino acid 



= NH3 + RCH(OH)COOH = R-CH20H + CO2 



Hydroxy-fatty Alcohol 



acid 



COOH • CH2 • CH2 • CH • NH2 • COOH + H2 



Glutamic acid 



= CH3CH2-CH2COOH + NH3 + CO2 



Butyric acid 



The decomposition of fats and lipoids results in the formation of 

 various fatty acids: 



CH2— OOC— C15H31 CH2— OH 



CH — OOC— C15H31 + 3H2O = CH —OH + 3Cir.H3i-COOH 



I Fatty acid 



CH2— OOC— C15H31 CH2— OH ^'''''""'■•^ '^"''^ 



fat (glyceryl tri-palmitate) Glycerol 



In addition to the organic acids, carbon dioxide is an important 

 product of most of these reactions. The solvent action of organic 

 acids compared to carbonic acid is suggested from the data in 

 Table 40. 



Under aerobic conditions, the organic acids do not persist for 

 long in the soil, but are soon decomposed more completely, even 

 to the final oxidation products, namely, carbon dioxide and water. 

 Under anaerobic conditions, the acids may persist for extended 

 periods of time. 



