BACTERIAL FERMENTATIONS 



H. A. BARKER, Department of Plant Biochemistry, University of California, 



Berkeley. California 



Early interest in bacterial fermentations was stimulated 

 mainly by a need to determine the chemical changes occurring 

 in food, soil, and other materials under anaerobic conditions or 

 to discover and produce compounds that might have industrial 

 applications. Abundant information on these aspects of fer- 

 mentation has accumulated over the years. More recently, the 

 center of interest has shifted to the analysis of the chemical 

 mechanism of fermentations, since anaerobic bacteria frequently 

 provide relatively simple and convenient systems for the study 

 of basic metabolic processes. 



The usefulness of bacteria for metabolic studies is dependent 

 in part upon two characteristic properties, the high rate and the 

 extraordinary degree of specialization of their energy-generating 

 mechanisms. These properties are perhaps even more highly 

 developed in anaerobic than in aerobic bacteria. They facilitate 

 the analysis of problems of intermediary metabolism by providing 

 a biological material that is relatively free of complicating side 

 reactions. 



Although individual species use highly specialized catabolic 

 reactions, anaerobic bacteria as a group possess the ability to 



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