The Exzyme Corporation has developed an approach for discovering metabolic pathways for arbitrary organic compounds. Our approach is inspired by E.J. Corey’s Nobel prize winning development of retrosynthesis, in which chemical transformations are applied – in reverse – to the target compound to find plausible precursors. The technique is iteratively applied until simple or commercially available reactants are reached. For our “retrobiosynthesis” approach, we develop a corpus of biochemical transformations and iteratively apply them to precursors. The result of applying the technique is a enzymatic pathway from carbon source to metabolite.