Fermentation and Industrial Microbiology

Fermentation for some products is anoxic (absence of Oj) for other products, oxic fermentation may be required. Fermentation processes have been used for thousauds of years to produce alcoholic beverages, sauerkraut, vinegar, pickles, cheese, yogurt, aud other foods. More receutly, fermentatiou has been applied to the production of a wide variety of organic acids, antibiotics, antibodies, complex plant metabolites, enzymes, and vitamins. Ethanol, the alcohol in alcoholic beverages, is the most widely produced chemical made by fermeutation. 

Another very important ch ical that has been made from biological feedstocks by fermentation for many years is lactic acid. Lactic acid is the most important hydrocarboxylic acid and is nsed to make a number of chemicals including pyruvic acid, acrylic acid, 1,2-propauediol, lactate esters, and polylactic add polymer. Fermentation of glucose with the intermediate prodnction of pyruvic acid is the leading process for making lactic acid, as shown in Reaction 16.10  

FIGURE 16.6 General outline of an industrial microbiology process for the synthesis of chemicals such as antibiotics details of this overall scheme may vary depending on the product made. 

This reaction summarizes a rather complex set of metabolic processes that, depending on the kinds of bacteria involved, may also produce ethanol and carbon dioxide. 

Great impetus was given to the technology of industrial microbiology in the 1940s with the establishment of fermentation processes to produce antibiotic penicillin, a bactericidal pharmaceutical that has saved millions of lives. Following penicillin, fermentation processes were developed for the production of numerous other significant antibiotics and other pharmaceuticals. 

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