Since Robert Knock, the Nobel Prize winner, proved that
succinic acid has a positive influence on human metabolism and
there is no risk of its accumulation in the human body, it has
been used in food industries. Succinic acid is an intermediate of
the tricarboxylic acid (TCA) cycle and one of the fermentation
end-products of anaerobic metabolism. Thus, it is synthesized
in almost all microbial, plant and animal cells. Those organisms
suitable for the efficient production of succinic acid can be
categorized into fungi and bacteria.