Microorganisms have 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 transformation of a yeast suspension 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 bacteria and yeast-chemical behaviors grew, other biotechnological uses for the microbes were found. A few examples include the use of the bacterium Lactobacillus acidophilus to produce yogurt, the exploitation of a number of different bacteria to produce a variety of cheeses, and the fermentation of cabbage to produce sauerkraut. In the agricultural sector, the discovery of the ability 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 (deoxyribonucleic 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 gene splicing technologies, which can be accomplished by various splicing and reannealing enzymes, or by the use of viruses or mobile regions of viral DNA (such as transposons) as vectors have allowed biotechnologists 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 excretion of human insulin by the bacteria allows the production of a large amount of insulin. Additionally, because the insulin is
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, hepatitis B, Karposi's sarcoma, rejection of transplanted organs, growth hormone deficiency, and cancer. The worldwide sales of medical 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 textile manufacture, agriculture, and nutrition. Enzymes discovered 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. Microorganisms are used to enhance the nutritional content of plants and other food sources. The growing nutraceutical sector relies in part on the nutritional enhancements afforded by microbes. Bacteria are also useful in providing a degree of resistance to plants. An example is the use of Bacillus thuringensis to supply a protein that is lethal to insect when they consume it. The use of bacterial insecticides has reduced the use of chemical insecticides, which is both a cost savings to the producer and less stressful on the environment. Other bacterial enzymes and constituents of the organisms are utilized to produce materials such as plastic.
A process known as DNA fingerprinting, which relies upon enzymes that are produced and operate in bacteria, has enabled the tracing of the fate of genes in plant and animal populations, and enhanced gathering of evidence at crime scenes.
The mode of growth of bacterial populations has also proved to be exploitable as a production tool. A prime example is the surface-adherent mode of bacterial growth that is termed a biofilm. Although not known at the time, the production of vinegar hundreds of years ago was, as now, based on the percolation of water through biofilms growing on wood shavings. Immobilized bacteria can produce all manner of compounds. As well, the cells can provide a physical barrier to the flow of fluid. This dynamic aspect has been utilized in a so far small-scale way to increase the production of oil from fields oil thought to be depleted. Bacteria can plug up the zones were water and oil flows most easily. Subsequent pumping of water through the field forces the oil still resident in lower permeability areas to the surface.
With the passing of time, the realized and potential benefits of microorganisms and the implementation of strict standards of microbe use, is lessening the concern over the use of engineered microorganisms for economic and social benefit. The use of microorganisms can only increase.
See also Bioremediation; Composting, microbiological aspects; DNA chips and micro arrays
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