Publisher: American Chemical Society (ACS)

Issue: 13

License:

Publication date(s): 2018/04/03 (print) 2018/03/13 (online)

Pages: 1997-2008

Volume: 57 Issue: 13

Journal: Biochemistry

Link: /doi/pdf/10.1021/acs.biochem.8b00169

URL: http://dx.doi.org/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 (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.