Cyclopropanes-functionalized hydrocarbons are excellent fuels. however, their synthesis is challenging and harmful for the environment. In this work we produced polycyclopropanated fatty acids in bacteria. These molecules can be easily converted into renewable fuels for high energy applications such as shipping, long-haul transport, aviation, and rocketry. We explored the chemical diversity encoded in the genome of thousands of bacteria to identify and repurpose naturally occurring cyclopropanated molecules. We identified a set of candidate iterative Polyketide Synthases (iPKSs) predicted to produce polycyclopropanated fatty acids (POP-FAs), expressed these PKSs in Streptomyces coelicolor and produced the POP-FAs. We determined the structure of the molecules and increased their production 22-fold. Polycyclopropanated fatty acid methyl esters (POP-FAMEs) were obtained by methyl esterifying the POP-FAs. Finally, we calculated the enthalpy of combustion of several POP fuel candidates to assess their potential as replacement for fossil fuels in energy demanding applications. Our research shows that POP-FAMEs and other polyketide derived POPs have the energetic properties for energy demanding applications for which sustainable alternatives are scarce.