Biocatalytic Routes to Lactone Monomers for Polymer Production

Monoterpenoids offer potential as biocatalytically derived monomer feedstocks for high-performance renewable polymers. We describe a biocatalytic route to lactone monomers menthide and dihydrocarvide employing Baeyer–Villiger monooxygenases (BVMOs) from <i>Pseudomonas</i> sp. HI-70 (CPDMO) and <i>Rhodococcus</i> sp. Phi1 (CHMO_Phi1) as an alternative to organic synthesis. The regioselectivity of dihydrocarvide isomer formation was controlled by site-directed mutagenesis of three key active site residues in CHMO_Phi1. A combination of crystal structure determination, molecular dynamics simulations, and mechanistic modeling using density functional theory on a range of models provides insight into the origins of the discrimination of the wild type and a variant CHMO_Phi1 for producing different regioisomers of the lactone product. Ring-opening polymerizations of the resultant lactones using mild metal–organic catalysts demonstrate their utility in polymer production. This semisynthetic approach utilizing a biocatalytic step, non-petroleum feedstocks, and mild polymerization catalysts allows access to known and also to previously unreported and potentially novel lactone monomers and polymers

Biocatalytic Routes to Lactone Monomers for Polymer Production

Monoterpenoids offer potential as biocatalytically derived monomer feedstocks for high-performance renewable polymers. We describe a biocatalytic route to lactone monomers menthide and dihydrocarvide employing Baeyer–Villiger monooxygenases (BVMOs) from <i>Pseudomonas</i> sp. HI-70 (CPDMO) and <i>Rhodococcus</i> sp. Phi1 (CHMO_Phi1) as an alternative to organic synthesis. The regioselectivity of dihydrocarvide isomer formation was controlled by site-directed mutagenesis of three key active site residues in CHMO_Phi1. A combination of crystal structure determination, molecular dynamics simulations, and mechanistic modeling using density functional theory on a range of models provides insight into the origins of the discrimination of the wild type and a variant CHMO_Phi1 for producing different regioisomers of the lactone product. Ring-opening polymerizations of the resultant lactones using mild metal–organic catalysts demonstrate their utility in polymer production. This semisynthetic approach utilizing a biocatalytic step, non-petroleum feedstocks, and mild polymerization catalysts allows access to known and also to previously unreported and potentially novel lactone monomers and polymers