How do you and your clothes get colour? It comes from molecules we call pigments. For example, there is a pigment called melanin which, depending on how it is made, can be so black that we call it ultra-black. This ultra-black pigment can potentially be very useful, including for coating solar panels, because it absorbs virtually all incoming light, making the material perform better. We can already produce and extract melanin today, but it is done through chemical processes that are energy-intensive and very polluting. It is therefore better to let nature help us. At Zuyd University, we are working with genetically modified bacteria that can produce melanin for us like small factories. The melanin ends up on the outside of the cell, so we can harvest it easily. This makes it not only cheaper, but also more sustainable. Our students can already produce simple black melanin. We hope to take the step to ultra-black melanin. In this way, we are making an important contribution to the development of new sustainable bio-based materials, from clothing to solar panels.