Bread, wine and beer need yeast to ferment, and cheese and yoghurt are possible thanks to bacteria during its processing. Many species of fungus are major sources of pharmacologically active drugs, such as antibiotics like Penicillin. Microorganisms are present in a lot of products we use and food we consume in our everyday life. They can do many things on their own, but thanks to synthetic biology, scientists are able to tailor these organisms so they can do even more and better things.

It can be difficult to imagine how this works at such a small scale, but think of a car with all its different parts: the engine, the battery, the chassis, the steering wheel, etc. Starting from the chassis, a mechanical engineer can build a new car using parts of others. Microorganisms are like biological chassis: researchers can reduce their genetic information and then add and organise genes to achieve certain purposes.

Following this approach, in R4B we explore bacteria – E.coli and B. subtilis- as a biotechnological tool in detoxification processes or production of antibiotics or vitamins. But we are not the only one exploring this field. Other European projects are facing similar challenges to ours, following different approaches. Chassy is one of these cases. Chassy develops yeast –Saccharomyces cerevisiae, Kluyveromyces marxianu and Yarrowia lipolytica- to make fat-based molecules for the cosmetics industry that would otherwise come from petroleum.

Although they are similar, and often put under the same umbrella, bacteria and yeasts have many differences. One of them is their genetic complexity, which is the reason why, historically, synthetic biologists have studied and worked with bacteria more. To take a specific example: E. coli’s genome is equivalent to 4.6 Mb while S. cerevisiae is to 12.1 Mb. This makes it more complicated to reduce it to its minimal genome. The first yeast genome-scale model of E. coli was published in 1997, what turned this microbe into one of the most used in biotechnology for decades. The genome from Saccharomyces cerevisiae followed shortly after in 2003, opening new doors for yeasts to conquer also the industrial field as they can provide products that are more difficult to get bacteria to produce.

In this context Chassy could help to develop yeasts into industrial cell factories. Yeasts are great suppliers of lipids, proteins and enzymes so they have many applications in chemical, food and pharmaceutical industries. In fact, the strains that are produced in Chassy will be optimised for the synthesis of the key precursor molecules necessary for the production of valuable lipid and aromatic compounds.

So, the choice between bacteria or yeast depends on a lot of factors: the final product we want them to produce, the environment for its growth… Yeast and bacteria are not competitors but different approaches to the development of new techniques and better tools to medicine, nutrition, chemistry, sustainability, waste treatment or safety. And they have both already manufactured important products like biofuel or biodegradable plastics. All of it thanks to the research conducted in synthetic biology. Chassy and Rafts4Biotech are not the only projects in these fields. There are many other projects, some of them are possible thanks to the funding of the European Commission. We encourage you to discover them and learn more about microorganisms applications!