468 PRINCIPLES OF SOIL MICROBIOLOGY 



The action of Bac. granulobacter pectinovorum upon starch, pentoses and 

 hexoses results 129 in the formation of acetone, butyl alcohol, hydrogen 

 and carbon dioxide, with various acids (butyric, acetic, lactic) as in- 

 termediary products. When aliphatic compounds with carboxyl 

 groups are acted upon by Bact. pyocyaneum, they become alkaline as 

 a result of the oxidation of the carboxyl groups. Compounds contain- 

 ing — CHO or — OH = CO— groups become acid as a result of oxi- 

 dation. 130 



The formation of butyric acid by the various butyric acid bacteria 

 under anaerobic conditions can be represented as follows: 



C 6 Hi, 6 = C 4 H 8 2 + 2 C0 2 + 2 H 2 



This process is much more complex than represented by the above 

 reaction, since other acids and various alcohols are also formed. The 

 acid itself may be formed as a result of the synthetic processes rather 

 than by direct decomposition. 131 



C 6 Hi 2 6 = 2 CH 3 • CO • COOH + 2 H 2 . 



2 CH S • CO • COOH = CH 3 • COH • COOH 



COOH 



CH 2 • OH. 



Decomposition of organic acids. Fatty-acids are thus formed from 

 poly- and mono-saccharides, from proteins and their derivatives. When 

 neutralized, these acids serve as good sources of energy for various 

 bacteria and fungi. The great majority of heterotrophic bacteria can 

 utilize malic, citric, fumaric, glyceric, succinic, formic, lactic, mucic, 

 and tartaric acids; a small number utilize acetic, propionic, quinonic 



39: 1-21. 1919; Speakman, H. B. The biochemistry of acetone formation from 

 sugars by Bacillus acetoethylicum. Jour. Biol. Chem., 64: 41-52. 1921. 



129 Speakman, H. B. Molecular configuration in the sugars and acid produc- 

 tion by Bacillus granulobacter pectinovorum. Jour. Biol. Chem., 58: 395-413. 

 1923. 



130 Supniewski, J. Recherches sur la transformation des combinaisons car- 

 bones par le Bacille pyocyanique. Compt. Rend. Soc. Biol., 89: 1377-1379. 

 1923. 



1,1 Neuberg, C, and Arinstein, B. Vom Wesen der Buttersiiure und Butyl- 

 alkoholgiirung. Biochem. Ztschr., 117: 269-314. 1921. 



