You've read about the biotechnology in the use of yeast to create a product like bread, but yeast is not the only organism that can be used to create something. In fact, the very first human insulin produced in a lab in 1978, used E. coli - to the dismay of readers whose only knowledge of E. coli is through news reports of foodborne illness - as an essential part of the process. The key to the production of human insulin by bacteria is recombinant DNA - DNA from one organism that is "recombined" in the DNA of another.
Who & Why?
The firm that produced the first human insulin is Genentech (now a member of the Roche Group). In fact, Genentech is generally credited with being the very first biotechnology firm. The founders, Boyd and Swanson, decided that the way to build a successful company was to produce a product with large commercial potential. From the 1920s and up until Genentech's success, insulin for human use was manufactured from the pancreas of slaughtered cows and pigs. It worked, but over time, many diabetics developed an allergic sensitivity to the animal insulin they received. If human insulin could be produced, the logic went, then that would eliminate the potential for an allergic reaction. Human insulin for human use would be the solution to a serious problem - and the market for human insulin at that time was large and growing. If they could just ...
Researchers decided to create a human gene for insulin and insert it into the genetic material of a bacterium. Once the genetic material was inserted into the bacterium, it was considered a "recombinant bacterium." They selected E. coli as the bacteria. (Why? That's another post.) Successfully creating the recombinant bacterium was the key to it all. To accomplish this in the lab, researchers:
1. created a human insulin gene.
2. removed a plasmid - a loop of DNA - from the bacteria.
3. inserted the human insulin gene into the loop.
4. returned the plasmid to the bacterium.
The DNA in the bacterium now contained material from humans and bacteria. It contained recombinant DNA.
The recombinant bacteria are placed in a fermentation tank and grown under optimal conditions. Since part of their "job" is to produce human insulin - because it is now part of their (recombinant) DNA - they produce human insulin. All that is left is to harvest and purify the insulin. bio = E. coli bacteria + technology = Recombinant DNA. Biotechnology!
The U.S. National Library Medicine at NIH video below, "How did they make insulin from recombinant DNA?, illustrates the process described above.