About the Seminar:
Arguably the most facile synthetic approach towards sustainable polyesters is through the ring-opening polymerization (ROP) of cyclic esters (or lactones). Robust methodology has been developed for the controlled ROP of these cyclic monomers at scale, but synthesis of these lactone monomers from bio-derived feedstocks can often be multi-step, energy intensive, low yielding, and time-consuming. A more desirable route would be a one-pot catalyzed transformation from the simple hydroxy acid precursor to the cyclic ester. A lipase enzyme, Candida antarctica lipase B (CALB), has been found to catalyze the enantioselective synthesis of (R,R)-lactide from alkyl lactate but with a maximum lactide yield of 56%. Using the tools of directed evolution, the stereoselectivity and substrate specificity of CALB can be tuned to produce the industrially relevant diastereomers of lactide and 8DL.