The Industrial Application of Enzymes
Enzymes are naturally occurring biological molecules found in all
living organisms, plant, animal and microorganisms such as bacteria.
All enzymes are proteins and, as with all proteins, are made up of a
chain or polymer of amino acids held together by peptide bonds. This
chain coils to form a specific three-dimensional globular shape,
which, typically, means an enzyme will only work with one specific
substrate. The purpose of an enzyme is to lower the activation energy
required for biochemical reactions to take place. As a result a
reaction catalysed by an enzyme will be much more efficient at
breaking down a substrate into its products and consequently are used
in industry for just this purpose. To obtain these enzymes scientist
look mostly tonaturally occurring microorganisms, as they are the most
productive producers, are easy to handle, can be grown in huge tanks
without light, and have a very high growth rate. This may sound all
very new and scientific but microorganisms have been used for brewing,
baking and alcohol production long before anybody knew of the
existence of enzymes. One of the earliest references can be found in
Homer's Greek poems dating from about 800 BC where he mentions the use
of enzymes in the production of cheese.
The starch industry has been using enzymes too for many years in the
production of 'artificial' sweeteners. Although sucrose is readily
available from the harvesting of cane or beet sugar, glucose and
maltose need extracting from starch by enzymic or chemical
extraction.Starch is a polymer where the individual units in the
polymer are glucose molecules. Enzymes that degrade starch are called
amylases. During both processes, chemical (typically acid-hydrolysis)
and enzymic, glycosidic bonds between these Î±-glucose molecules are
hydrolysed leaving only single sub-units of glucose. However, in
comparison with enzymic preparation, acid-hydrolysis tends to be
costly and time consuming with the final yield often being of poor
purity. The first use of enzymes in the 1960's heralded a breakthrough
in the production of sweet sugars from starch.
The main advantage of using an amylase (an amylase being any enzyme
which breaks down starch - amylose) is that not only does the reaction
take place spontaneously there is no need for cleansing or washing
following the process. As you can imagine when using chemicals for
this process there tend to be left over residues which taint the
flavour of the final sugar/syrup, this is not so when using an enzyme.
So how does it work?
Having initially added amylases to the starch what is left are glucose
polymers called Maltodextrins. These Maltodextrins are not at all
sweet as they contain dextrins and ogliosacharrides("oligo" meaning
"few" and "saccharide" meaning...