Re: The history of peptone

hi Nga,

Your question is very interesting, because it's a question that most scientists would never even think about. As you know, peptone is a substance that we put into growth media when we want to grow microbes. Most of us don't think very much about where it comes from, why we use it or even what it is!

So let's start with what it is. Peptone is a complex substance obtained by treating a mixture of proteins with enzymes (called proteases) or acids. This process is called partial hydrolysis - it breaks down the proteins into short pieces called peptides. Microbes can then transport the peptides into the cell and use them for growth and metabolism. There are actually lots of different kinds of peptone - you can make it from animal proteins (by digesting meat) or plant proteins, such as soy bean extract. So peptone is not a single defined compound - it's the name for a complex mixture of peptides that can be obtained from different sources. Often in science, we use something because somebody tried it once, long ago and it worked - we don't always have a full understanding of what we use!

I suppose the "history of peptone" is really the history of microbiology. Microbes have been studied since the early 17th century, when the first microscopes were invented. However, scientists did not really learn how to isolate and grow microbes until the 19th century. Some of the scientists who pioneered microbial culture are very famous - Louis Pasteur, Joseph Lister, Robert Koch and Julius Petri.

I found a nice article entitled History of the Agar Plate which describes the development of growth media. It mentions the fact that peptone was produced in the 19th century as a pharmaceutical product for people, before being added to microbiological media. I don't know when it was first used in microbiology, but I would not be surprised if it happened in the laboratory of one of the scientists that I mentioned earlier. "Meat extract" (broth from boiled meat) was often used to grow microbes and I expect that peptone was a natural progression from that.

You can learn more about culturing bacteria at this site. You can also read some highlights in the history of microbiology or look at a timeline of events in microbiology. The last link is part of a larger site called Microbe World that you might find interesting.