Biocatalytic Routes to Lactone Monomers for Polymer Production

• Published in: Biochemistry (Easton) Vol. 57; no. 13; pp. 1997 - 2008
• Main Authors: Messiha, Hanan L, Ahmed, Syed T, Karuppiah, Vijaykumar, Suardíaz, Reynier, Ascue Avalos, Gabriel A, Fey, Natalie, Yeates, Stephen, Toogood, Helen S, Mulholland, Adrian J, Scrutton, Nigel S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 03.04.2018
• Subjects: Bacterial Proteins - chemistry; Catalysis; Lactones - chemistry; Mixed Function Oxygenases - chemistry; Monoterpenes - chemistry; Pseudomonas - enzymology; Rhodococcus - enzymology
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/acs.biochem.8b00169

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 Pseudomonas sp. HI-70 (CPDMO) and Rhodococcus sp. Phi1 (CHMOPhi1) 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 CHMOPhi1. 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 CHMOPhi1 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.