Maurice MürkösterPhD student

Green bacteria for a greener environment

Did you ever wonder how green glowing bacteria could help in producing sustainable plastic? One way of producing more sustainable plastic is by using proteins to produce the molecules, or chemical building blocks, that plastic is made of. Proteins can be imagined as little machines in a cell that perform certain tasks, for example turning one molecule into another. Many proteins can also be used in industrial applications and for this they first have to be produced. One way to produce industrial proteins is in bacteria. This is not an easy task for the bacterium and involves several steps. One of these steps and the one we will focus our attention to is protein folding. To better understand protein folding, imagine a pearl necklace. Each pearl on this necklace is one amino acid, a building block, in our protein. To become a functional protein, this necklace has to be folded in a specific way that is unique for each protein. If this folding goes wrong, the protein has no function and will just clump together with other wrongly folded proteins. If there are only a few wrongly folded proteins the bacterium can easily remove them, but if there are too many wrongly folded proteins the bacterium can not remove them anymore and will get stressed. However, there are two solutions for this problem. Solution one is a group of proteins called chaperones. Similar to their name givers, chaperone proteins look after unfolded proteins and help them with their correct folding. Solution two is a stress sensor for our bacteria. This sensor reacts when our cells are stressed and then starts to produce a protein. We can use this to let our bacteria produce a protein called green fluorescent protein or GFP in short. This protein, as the name suggests, has a green colour that we can detect. In addition to that, we can also produce more than one protein when our cells are stressed. This means that we can not only produce GFP to detect if our cells are stressed, but also chaperone proteins that then can reduce this stress. With this method to easily detect stress and our chaperones that then can help reduce stress we have an easy way to find the optimal conditions to produce new and interesting proteins. Many proteins cannot yet be produced on a large enough scale to use them in industrial applications. This is largely due to low production yields that are often associated with incorrect folding and stress for the bacterium. Detecting the green colouration of a bacterium is an easy way to find the best conditions to produce new proteins that then can be used to make new and more sustainable building blocks for plastic and a lot more things.