The potential lies primarily in the ability of microorganisms to produce hydrocarbons on the basis of renewable raw materials. This means that the resulting fuels are closer to CO2-neutral. In addition, the corresponding processes offer new product potential for German agriculture. For example, farmers could convert plant residues into new products such as hydrocarbons.

We use the gram-positive bacterium Bacillus subtilis for our so-called ‘bottom-up’ approach, as well as the oleaginous yeast Yarrowia lipolytica as part of a ‘top-down’ approach. A selection criterion for both organisms was their absolutely safety. B. subtilis is found everywhere in the natural world, also as an important coloniser in our intestines. The same is true of Y. lipolytica, which can be found on cheese and in marzipan, among other things. We use B. subtilis to create hydrocarbon molecules from scratch, whereas Y. lipolytica breaks down the yeasts – so-called oil bodies – from hydrocarbons.

The principle involves splitting off various cellular metabolites from unwanted groups, both through enzyme catalysis and chemical catalysis, which results in molecules containing only carbon and hydrogen.

We are currently working on the further improvement of the oil bodies formed by Y. lipolytica, as well as the fine-tuning of the involved enzymes. We are also looking at how we can scale up the chemical-catalytic process.

The processes that we have developed are just one part of a larger puzzle towards the renewable production of fuels. Because it is difficult to power trucks and airplanes with batteries alone, we are focusing above all on alternatives to kerosene and diesel. Our fuels should also be low-emission. However, the greatest potential lies in each of us and in our ability to use our resources in a more energy-efficient and ecologically sound manner. When it comes to fuel consumption, we have to change our ways – even with the very best microbial cell factories.

Interview: Beatrix Boldt