CHAPTER 



THE CHEMISTRY OF 

 BUTYRIC ACID-BUTANOL FERMENTATIONS 



The butyric acid fermentation of sugar and lactate was 

 discovered by Pasteur in 1861. During the next half century 

 Fritz, Beijerinck, Duclaux, Winogradsky, Weizmann, and 

 others studied various butyric acid fermentations and 

 showed that they are caused mainly by several species of 

 Clostridia that are widely distributed in nature and as a 

 group are able to decompose a great variety of substrates, 

 including sugars, polysaccharides, and hydroxy acids. The 

 main products of these fermentations were identified as 

 acetic and butyric acids, rz-butanol, ethanol, acetone, some- 

 times isopropanol, carbon dioxide, and hydrogen. Also 

 techniques were devised for the commercial exploitation of 

 the fermentation of starch by Clostridium acetobutylicum 

 for the production of acetone and butanol. 



Early studies in the chemistry of the butyric acid-butanol 

 fermentations were hampered by the variety of the products 

 and the difficulties associated with their quantitative estima- 

 tion. Precise and extensive quantitative information con- 

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