Microorganisms have been found in almost every inhospitable
environment on earth. These environments include the superheated
waters of hydrothermal vents, the frozen dry valleys of Antarctica,
and acid mine drainage fields. For the most part, microbes living
in these environments do nothing fundamentally different than
those living in more mundane environments; they are simply equipped
to carry out the routine functions of life under extreme conditions.
Many microbiologists are "bioprospecting" in these environments
for new ways to do everything from cleaning clothes to treating
disease.
Enzymes are the target molecule
for most bioprospectors. They are manufactured by organisms to
catalyze the myriad reactions necessary to sustain life. Commercial
applications of enzymes include food and textile processing, additives
in detergents, and animal feed. Extremozymes, enzymes that function
under extreme conditions, present possibilities for new commercial
applications. For example, many manufacturing processes are more
efficient at higher temperatures. Therefore, enzymes isolated
from hyperthermophiles (heat-loving microbes) are of particular
interest to manufacturers. Enzymes from alkaliphilic microbes
(those that grow at high pH) are useful additives to laundry detergents
because they are able to degrade the common components of stains
(proteins, carbohydrates, and lipids) in the high pH environment
of soapy water. The list goes on.
Because culturing commercial quantities
of extremophiles is usually difficult and requires special facilities,
the genes encoding the information used to produce the enzymes
are often cloned into a bacterium that grows at more normal conditions.
This allows commercial production of the enzyme at a reasonable
cost. By directly cloning DNA extracted from extreme environments
and then screening the clones for enzyme activity, the initial,
and often most difficult, step of culturing extremophiles can
be avoided. This strategy is employed by some biotechnology companies
to increase their chances of finding new products. Continued efforts
to exploit the extremozymes will undoubtedly expand the range
of useful applications for enzymes in biotechnology.
---David C. Smith, Assistant Professor,
GSO
