In vitro biosynthesis of polyesters with isolated enzymes in aqueous systems and organic solvents

In vitro synthesis of aliphatic polyesters was achieved by lipase-catalysed polymerization. A lipase-catalysed polycondensation of a dicarboxylic acid and a glycol proceeded in an aqueous medium in which a dehydration took place in water. From a combination of sebacic acid and 1,8-octanediol, the corresponding polyester with a molecular weight of 1600 was obtained. Lipase also catalysed a ring-opening polymerization of lactones with different ring sizes. The polymerization behaviors depended on the lipase origin and the monomer structure. Macrolides (12-, 13- and 16-membered) showing much lower anionic polymerizability were enzymatically polymerized faster than epsilon-caprolactone, The lipase-catalysed polymerizability of these lactones was evaluated by Michaelis-Menten kinetics. The enzymatic ring-opening polymerization of lactones was expanded to an enantioselective polymerization of 3-methyl-4-oxa-6-hexanolide. The polymerization of the (S)-isomer proceeded much faster than that of the (R)-isomer. Single-step synthesis of end-functional polymers, methacryl-type macromonomer and a telechelic polyester having a carboxylic acid group at both ends, was achieved by the polymerization in the presence of vinyl methacrylate and divinyl sebacate, respectively. Lipase catalysis provided the copolymerization of lactones, dicarboxylic acid divinyl esters and glycols, in which two different types of polymerization-ring-opening polymerization and polycondensation-simultaneously occurred via the same acyl-lipase intermediate. (C) 1998 Published by Elsevier Science Limited. All rights reserved.