Page 32 - Chemical and process design handbook

Speight_Part 1_E&F 11/7/01 3:03 PM Page 1.18

FERMENTATION

Fermentation processes produce a wide range of chemicals that comple-
ment the various chemicals produced by nonfermentation routes. For
example, alcohol, acetone, butyl alcohol, and acetic acid are produced by
fermentation as well as by synthetic routes. Almost all the major antibi-
otics are obtained from fermentation processes.
Fermentation under controlled conditions involves chemical conver-
sions, and some of the more important processes are:

1. Oxidation, e.g., ethyl alcohol to acetic acid, sucrose to citric acid, and
dextrose to gluconic acid
2. Reduction, e.g., aldehydes to alcohols (acetaldehyde to ethyl alcohol)
and sulfur to hydrogen sulfide
3. Hydrolysis, e.g., starch to glucose and sucrose to glucose and fructose
and on to alcohol
4. Esterification, e.g., hexose phosphate from hexose and phosphoric acid

1.18