Biomedical Engineering Reference
In-Depth Information
dimethylsulfoxide and pH shift may be used for this purpose. If enzyme release is not
complete, then cell disruption may be essential.
The processes used to produce these industrial enzymes have much in common with our
later discussions on processes to make protein from recombinant DNA.
8.6. ME DICAL AND INDUSTRIAL UTILIZATION OF EN ZYMES
Enzymes have been significant industrial products for over a century. The range of poten-
tial application is still increasing rapidly. With the advent of recombinant DNA technology, it
has become possible to make formerly rare enzymes in large quantities and, hence, reduce
cost. Also, in pharmaceutical manufacture, the desire to make chirally pure compounds is
leading to new opportunities. Chirality is important in a product; in a racemic mixture,
one enantiomer is often therapeutically useful while the other may cause side effects and
add no therapeutic value. The ability of enzymes to recognize chiral isomers and react
with only one of them can be a key component in pharmaceutical synthesis. Processes that
depend on a mixture of chemical and enzymatic synthesis are being developed for a new
generation of pharmaceuticals.
Technological advances have facilitated the use of enzymes over an increasingly broad
range of process conditions. Enzymes from organisms that grow in unusual environments
(e.g. deep ocean, salt lakes, hot springs, and industrial waste sites) are increasingly available
for study and potential use. New enzymes and better control of reaction conditions allow the
use of enzymes in the presence of high concentrations of organics, in high salt aqueous envi-
ronments, or at extreme temperatures, pH, or pressures. As we couple new insights into the
relationship of enzyme structure to biological function with recombinant DNA technology,
we are able to produce enzymes that are human designed or manipulated (Chapter 14).
We no longer need to depend solely on natural sources for enzymes.
While there are many reasons to be optimistic about increasing use of enzymes, the
number of enzymes made at high volume for industrial purposes evolves more slowly. In
2010, worldwide sales of industrial enzymes were at $3.3 billion, and the sales are projected
to grow to $4.4 billion by 2015. The products made in enzyme processes are worth billions of
dollars. Table 8.6 lists some industrially important enzymes.
Proteases hydrolyze proteins into smaller peptide units and constitute a large and indus-
trially important group of enzymes. Proteases constitute about 60% of the total enzyme
market. Industrial proteases are obtained from bacteria (Bacillus), molds (Aspergillus,
Rhizopus, and Mucor), animal pancreas, and plants. Most of the industrial proteases are endo-
proteases. Proteases are used in food processing, such as cheese making (rennet), baking,
meat tenderization (papain, trypsin), and brewing (trypsin, pepsin); in detergents for the
hydrolysis of protein stains (subtilisin Carlsberg); and in tanning and the medical treatment
of wounds.
Pectinases are produced mainly by A. niger. The major components in pectinases are pectin
esterase, polygalacturonase, and polymethylgalacturonatelyase. Pectinases are used in fruit
juice processing and wine making to increase juice yield, reduce viscosity, and clear the juice.
Lipases hydrolyze lipids into fatty acids and glycerol and are produced from animal
pancreas, some molds, and yeasts. Lipases may be used to hydrolyze oils for soap
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