Algaenan has been suggested to be one of the main precursors of certain kerogens. It is a non-hydrolysable and insoluble biomolecule of high molecular weight. It has been found in a limited number
of microalgae species. There is considerable uncertainty about its formation and preservation, as well
as its role in kerogen formation and the implications for the global C cycle. We tested whether the
cyanobacterium Chlorogloeopsis fritschii can synthesise a biomacromolecule similar to algaenan with
potential to contribute to kerogen via selective preservation.