The use of the element fluorine to modify active substances is an important tool in modern drug development. A team at Goethe University Frankfurt has now achieved an important “first” by successfully fluorinating a natural antibiotic via targeted bioengineering. With this method, an entire substance class of medically relevant natural products can be modified. The method has enormous potential for the manufacture of new antibiotics against resistant bacterial pathogens and for the (further) development of other drugs. The startup kez.biosolutions GmbH will bring these research results to the application stage (Nature Chemistry, DOI 10.1038/s41557-022-00996-z).