Why is biosafety so important in synthetic biology, especially in a competition like iGEM?
For an example, we can use our project. In our project, we used PCR-based methods to break the pollen´s exine and get their DNA. For that, we want to use E. coli by implementing an enzyme that dismantles cellulose and pectin, which the plant cell wall consists of. And in this way, an altered E. coli bacterium has the ability to dismantle cellulose and pectine, and with those abilities, it could bring great destruction to the environment because the cell wall of green plants and many algae are made out of cellulose and pectine.
Therefore we want to use a kill switch which for example releases a toxin and thus killing them. A different way would be making them dependent from a substance which they usually could produce by themselves but was cut out to prevent them from producing it and so making them dependent on this substance because they need it for their basic functions.
What is a kill switch ?
If an activator, which is defined in the kill switch, like ultraviolet hits the bacteria, the kill switch is being activated and destroys the bacteria from the inside. As explained in the previous paragraph, the kill switch is there to prevent an outbreak and there are many ways to use a kill switch. One example is a kill switch by Team Wageningen UR 2014 (), which has two toxins called Kid and Zeta and two antitoxins called Kis and Epsilon against those toxins. But the toxin and its antitoxin are on separate plasmids and so created an interdependent system. If the production of only one antigen, which needs a specific substance to be produced, stops the cell will die or one plasmid gets transferred to a wildtype cell, the antitoxin for the toxin on the plasmid is not present, thus killing the recipient.