Biobased and Biodegradable Furandicarboxylate Polyesters: Linking Molecular Structure to Enzymatic Hydrolyzability

Biobased, biodegradable polyesters are key to advancing a circular polymer economy by ensuring complete microbial utilization of such polyesters in targeted receiving environments. Extracellular enzymatic hydrolysis is often the rate-limiting step in overall polyester biodegradation. This work explores the hydrolytic activity of two esterases, Humicola insolens cutinase (HiC) and Rhizopus oryzae lipase (RoL), on a large set of 30 aliphatic-aromatic copolyesters. The copolyesters varied systematically in monomer composition, with most containing biobased 2,5-furandicarboxylic acid (F) and, for comparison, some containing fossil-derived terephthalic acid (T). The type and content of the aromatic diacid strongly influenced enzymatic hydrolysis: increasing the aromatic diacid content decreased hydrolysis rates, with F-containing copolyesters being consistently more hydrolyzable than their T analogues at the same aromatic diacid content. Hydrolyzability was further modulated by aliphatic diol and diacid chain lengths, with the combination of a short diol with longer-chain diacids favoring hydrolysis. HiC displayed broad activity across all copolyesters, whereas RoL was active only on (parts of the) polyesters with low aromatic content. By assessing the effect of copolyester chemical structure on polyester enzymatic hydrolyzability, this work informs the design of biobased polyesters with desired biodegradability performance.