As effective as fossil fuels may be, their impact on the planet cannot be overstated. Now researchers at Berkeley Lab have coaxed bacteria into directly producing a new biofuel with an energy density significantly higher than jet fuel.

The new fuel candidate molecules are known as polycyclopropanated fatty acid methyl esters (POP-FAMEs), and they’re made up of seven sets of cyclopropane rings. These are rings of three carbon atoms bonded into triangular shapes, which forces the bonds into a 60-degree angle. The strains of that sharp angle holds high potential energy that can be released during combustion.