Microbiology and Immunology

Economic uses and benefits of microorganisms WORLD OF MICROBIOLOGY AND IMMUNOLOGY

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ECOLOGY OF THE ORAL CAVITY• see

MICROBIAL FLORA OF THE ORAL CAVITY, DENTAL CARIES

ECOLOGY OF THE STOMACH AND

GASTROINTESTINAL TRACT•seeMICROBIAL

FLORA OF THE STOMACH AND GASTROINTESTINAL TRACT

ECONOMIC USES AND BENEFITS OF

MICROORGANISMSEconomic uses and benefits of microorganisms

Microorganismshave been used as tools for the production of

products for millennia. Even in ancient times, the ability to

produce vinegar by allowing water to percolate through wood

shavings was known and widely practiced. Likewise, the

transformationof a yeastsuspension into beer or a suspension

of crushed grapes into wine was common knowledge. The

basis of these events may not have been known, but that did

not impede the sale or trade of such products.

These economic uses of microorganisms are the earliest

examples of biotechnology. As the knowledge of bacteriaand

yeast-chemical behaviors grew, other biotechnological uses

for the microbes were found. A few examples include the use

of the bacterium Lactobacillus acidophilusto produce yogurt,

the exploitation of a number of different bacteria to produce a

variety of cheeses, and the fermentationof cabbage to produce

sauerkraut. In the agricultural sector, the discovery of the abil-

ity of Rhizobium spp.to convert elemental nitrogen to a form

that was useable by a growing plant, led to the use of the

microorganism as a living fertilizer that grew in association

with the plant species.

In more modern times, the use of microorganisms as

biotechnological agents of profit has not only continued but

has explosively increased. Indeed the biotechnology sector as

it is recognized today, is already a multi-billion dollar sector

worldwide.

The unraveling of the structure of DNA (deoxyribonu-

cleic acid), various species of ribonucleic acid(RNA), and the

various processes whereby the manufacture of protein from the

nucleic acid templates occurs was pivotal in advancing the use

of microorganisms as factories. As important was the discovery

of how to remove DNA from one region of the genome and

move the DNA in a controlled way to another region of the

same DNA, or DNA in a completely different organism

(prokaryotic or eukaryotic). These genesplicing technologies,

which can be accomplished by various splicing and reanneal-

ing enzymes, or by the use of virusesor mobile regions of viral

DNA (such as transposons) as vectors have allowed biotech-

nologists to create what are termed “designer genes,” which are

designed for a specific purpose. This ability has fueled the use

of microorganisms for economic gain and/or benefit.

The gene for the production of human insulin has been

transferred into the genome of the common intestinal tract

bacterium Escherichia coli. Successful expression and excre-

tion of human insulin by the bacteria allows the production of

a large amount of insulin. Additionally, because the insulin is

identical to that produced in a human being, the chance of

immune reaction against the protein is virtually nonexistent.

The example of insulin reflects both the health benefit of the

use of microbes and the economic benefit to be realized, since

the mass production of insulin that is possible using bacteria

lowers the cost of the product.

Other medical uses of microorganisms, particularly in

the production of antibiotics, have been the greatest boon to

humans and other animals. The list of maladies that can now

be treated using microbiologically derived compounds is

lengthy, and includes cystic fibrosis, hemophilia, hepatitisB,

Karposi’s sarcoma, rejection of transplanted organs, growth

hormone deficiency, and cancer. The worldwide sales of med-

ical and pharmaceutical drugs of microbial origin now

exceeds U.S. $13 billion annually.

Microorganisms have also been harnessed as factories

to produce compounds that are used in areas as divers as tex-

tile manufacture, agriculture, and nutrition. Enzymes discov-

ered in bacteria that can exist at very elevated temperatures

(thermophilic, or “heat loving” bacteria) cab be used to age

denim to produce a “pre-washed” look. Similar enzymes are

being exploited in laundry detergent that operates in hot water.

Dispensing beer into kegs.

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