The fed-batch operation described previously can be also shown to yield a superior
performance (a higher yield or higher productivity) for certain chemical and
biochemical reactions that exhibit a maximum in the overall reaction rate or to
maximize the selectivity of a specific product in systems of multiple reactions such
as biological reactions and polymerization reactions. Examples include inhibited
enzyme reactions and autocatalytic reactions, reactions in which one of the products
acts as a catalyst, certain adiabatic reactions, and series parallel reactions. Fermentation
and cell cultures are autocatalytic reactions in the sense that the cells produced
are in turn producing additional cells, and it is not surprising to find that most of the
industrially important fermentations are carried out in fed-batch mode. Extensive
reviews of fed-batch techniques5–7,145,146 are available elsewhere.