The corn starch processing industry provides a very good example of how biocatalysts can be successfully employed in bioprocessing on a very large commercial scale (maize starch processing).
The chemical processes were totally replaced in the starch-processing. The enzyme-controlled starch processing uses a variety of different amylases and glucose isomerases. The advantages are:
Glucose isomerase is an excellent example of the application of enzyme technology. Glucose isomerase enzymes catalyse the isomerization of D-glucose to D-fructose, a reaction that is reversible.
With batch reactors and using soluble enzymes for the conversion large enzyme dosages are required, resulting in a costly process. Because glucose isomerases are intracellular enzymes its own production does not yield as much enzyme as those produced extracellularly. Therefore, they have higher production costs. In order to overcome the inefficiency of the enzyme and still run a commercially viable process it was essential to keep reusing the enzyme, which was achieved by enzyme immobilization.