Bacteria in biotech – introduction
Find out how and why we use bacteria to improve our lives, and discover how the DNA revolution has led to new uses for bacteria.
Making use of bacteria: then and now
For millennia, we humans have been using bacteria to meet our needs. Since ancient times, we have used bacteria (despite not knowing that they existed!) in producing yoghurt, cheese and other fermented foods. We have also ‘used’ the large population of bacteria in our digestive system to help us break down food and make vitamins.
Today, we put bacteria to use in many more ways. Bacteria break down our waste, clean up oil spills, produce fuel, make medically important proteins and much more. Crucially, scientists are now able to modify the DNA within bacteria, leading to new uses for bacteria in the lab and beyond.
How humans use bacteria
We use bacteria to improve our lives in many ways, for example, in healthcare, industry, agriculture and fuel production.
Find out more about what bacteria are.
Find out more about Ancient biotechnology.
Our Cheesemaking resources are an example of how we use bacteria for good.
The DNA revolution: a starring role for bacteria
The second half of the 20th century saw rapid breakthroughs in our understanding of how DNA (the genetic material within every cell) functions. Within a couple of decades, scientists discovered what DNA looks like, how it acts as instructions for making the cell’s proteins, how DNA sequences can be altered and how DNA can be moved between different species.
Bacteria – particularly the bacterium Escherichia coli – have been central to this revolution. It was E. coli that was the first host for foreign DNA, and plasmid DNA from E. coli has been a crucial tool for working with pieces of DNA from all species.
Bacterial DNA
Bacteria have a single circular chromosome that is located in the cytoplasm in a structure called the nucleoid. Bacteria also contain smaller circular DNA molecules called plasmids.
For further information, see articles E. coli – the biotech bacterium and Bacterial DNA – the role of plasmids.
We can add foreign DNA to bacteria
As part of the DNA revolution, technologies have been developed for introducing DNA (such as a gene) from one species into another. Bacteria are particularly good at accepting foreign DNA, and introducing genes into bacterial cells is now routine. This procedure is a first step to making bacteria that can do new and useful things.
Bacteria that contain introduced DNA are classified as new, genetically modified organisms. For this reason, the conditions of their use are strictly controlled. The vast majority of all genetically modified bacteria never leave the laboratory, where they are used as tools for manipulating DNA and making proteins.
For further information, see the articles How to add foreign DNA to bacteria and Bacterial libraries for improving proteins.
For further information, see the article: DNA lab.
We use bacteria as protein factories
Bacteria can translate foreign genes into proteins – and scientists have ways to ensure that the bacteria make the proteins in large amounts. For these reasons, bacteria can function as ‘protein factories’, producing medically important proteins and others. Insulin, for treating diabetes, was the first protein to be produced in bacteria for medical use.
Fermentation vessel for bacteria
Many proteins, particularly medicines, are produced by expressing the genes that encode them in bacteria. To obtain the proteins in industrial amounts, bacteria are grown in large fermentation vessels. They are then harvested, and the protein of interest is purified away from bacterial components.
For further information, see these articles: Proteins – what they are and how they’re made and Producing foreign proteins in bacteria.
We can give bacteria useful functions
Carrying a foreign gene can change how a bacterium behaves – particularly if the gene is expressed. For instance, bacteria that express a foreign fluorescent protein will themselves fluoresce. Scientists use this phenomenon to develop bacteria with characteristics that are useful to humans – like producing fuels, breaking down waste and acting as markers of bacterial infection.
Bacterial library
In a bacterial library, each bacterium contains a different DNA sequence. Each DNA sequence is housed in the same cloning vector.
For further information, see the article: Giving bacteria new and useful functions.
Useful link
The Microbiology Information Portal website is full of useful and interesting microbiology resources.
