The new dawn of the bio-based chemical industry over the last 20 years has seen an ever growing interest in the synthesis of new bio-based polymers. The building-blocks of these plastics, also known as platform molecules, contain significantly more chemical functionality than their petrol-derived counterparts. The consequence is that bio-based polymers often contain greater residual chemical functionality in their chains, with groups such as alkenes and hydroxyls commonly observed. The unique selectivity of enzymes, along with their remarkable catalytic activity, constitute a powerful tool for transforming renewable feedstocks and adding value to a wide array of building blocks produced by the bio-based chemistry and biotechnology sectors. In this work, Candida antarctica lipase B (CaLB) was used to catalyze the synthesis of functional polyesters based on various functional dicarboxylic acids (and their derivatives) and several aliphatic diols. Their post-polymerization modification was also achieved through Michael additions to the alkenes and crosslinking of the lateral hydroxyl groups. The same enzymatic preparation was also used for the terminal coupling of poly(hydroxyalkanoates) with a) dimethyl itaconate in order to introduce reactive side chain vinyl and b) biocompatible poly(ethylene glycol) in order to tune the polymer’s hydrophilicity properties. Various biocatalysts belonging to the Serin-hydrolase family were tested for the green synthesis of bio-based aliphatic polyesters. The obtained polymers were thoroughly characterized and the biocatalyst’s selectivity elucidated via a chain-length screening. This work sheds light on the possibility of synthesizing, through enzymatic catalysis, functional, clickable oligoesters that can be further cross-linked or coupled with end-chain moieties in a 2nd reaction step.

Chemo-enzymatic tools for the green synthesis of bio-based polyesters

2019 Spring National Meeting

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