Introduction to Biochemical Engineering 52:108
Enzyme kinetics lab: Amylase Activity
This lab provides a short, one step assay for the enzymes,
-amylase (EC 22.214.171.124).
breaks down starch (and glycogen, since the two are chemically very similar) by addition of
water between glucose units (hydrolysis).
The end products of the amylase reaction are shorter
polymers of glucose along with the disaccharide maltose, while glucoamylase liberates single
Amylase occurs in mammalian saliva and small intestines and is found in the
intestinal tract of most animals. It is also common in plants, where it degrades stored starch and
in some bacteria and fungi that attack plants. Glucoamylase occurs only in fungi and selected
Both types of amylases are industrially significant in the conversion of biomass to
refined sugars and sweeteners.
Corn refiners separate corn kernels into starch, oil, protein and fiber and convert these
components into higher value products (CRA, 2001).
Major products from the refining industry
include corn sweeteners, ethanol and starch (See Figure 1).
In addition, corn and byproducts of
corn such as, glucose, starch, and corn steep liquor are used as feedstocks for biological reactors
which yield organic acids, amino acids, vitamins, and alcohols (Blanch and Clark, 1996).
Increasing biological production rates and fermentation yields while maintaining low operating
and purification costs will ultimately increase the competitiveness of renewable, corn-based
resources with petrochemical methods of commodity production.
Corn Refining process
One key enzyme which adds value to the corn refining process is
-amylase. In fact, this
enzyme is widely used in many industries such as pharmaceuticals, baking, detergents, sewage
treatment, natural sweeteners, and animal feeds (Guzman-Maldonado et al. 1995).
catalyzes hydrolysis of
-1, 4-glucosidic linkage of
-1, 4-glucans, such as starch, glycogen, and
Starch hydrolysis by amylase to produce maltodextrins is one of the major industrial
Further saccharification requires the addition of glucoamylase (also
known as amyloglucosidase). Glucoamylase attacks both exo-(1-4) and branch-point (1-6)-
linkages to produce glucose.